OCaml Changelog

• ocaml-index
  • Bump magic number after index file format change (#1886)

Features

• Enable experimental project-wide renaming of identifiers (#1431)

• merlin binary
  • Support for OCaml 5.3
  • Use new 5.3 features to improve locate behavior in some cases. Merlin no
    longer confuses uids from interfaces and implementations. (#1857)
  • Perform less merges in the indexer (#1881)
  • Add initial support for project-wide renaming: occurrences can now return
    all usages of all related definitions. (#1877)
• vim plugin
  • Added support for search-by-type (#1846)
    This is exposed through the existing :MerlinSearch command, that
    switches between search-by-type and polarity search depending on the
    first character of the query.

Features

• Add a new server option standardHover, that can be used by clients to
  disable the default hover provider. When standardHover = false
textDocument/hover requests always returns with empty result. (#1416)

• Add initial OCaml 5.3 support (#487, @NathanReb, @hhugo, @nojb)

• Initialise OCaml 5.3's lexer with the keywords setting from OCAMLPARAM or the new -keywords driver's CLI option to allow the standalone ppx driver to process old packages using effect as an identifier (#535, @dra27, @NathanReb)

• Add Pprintast.binding, longident and payload (#542, @mattiasdrp)

• Fix deriving_inline round-trip check so that it works with 5.01 <-> 5.02 migrations (#519, @NathanReb)

• Add ppxlib's AST pretty-printing utilities in Ppxlib.Pp_ast and a ppxlib-pp-ast executable in a new separate ppxlib-tools package (#517, #525, #537, @NathanReb)

• Change -dparsetree from a sexp output to a pretty printed AST, closer to what the compiler's -dparsetree is. (#530, @NathanReb)

• Add Parsetree documentation comments to Ast_builder functions (#518, @patricoferris)

• Support class type declarations in derivers with the new, optional arguments {str,sig}_class_type_decl in Deriving.add (#538, @patricoferris)

(Changes that can break existing programs are marked with a "*")

Restored backend:

• #12954: Restore the MSVC port (David Allsopp, Antonin Décimo, Samuel Hym, and Miod Vallat, review by Nicolás Ojeda Bär)

• #13093: Allow building the MSVC port with clang-cl. (Antonin Décimo, review by Nicolás Ojeda Bär, Samuel Hym, David Allsopp and Sébastien Hinderer)

Language features:

• #12309, #13158: Add syntax support for deep effect handlers (Leo White, Tom Kelly, Anil Madhavapeddy, KC Sivaramakrishnan, Xavier Leroy and Florian Angeletti, review by the same, Hugo Heuzard, and Ulysse Gérard)

• #11736, #12664, #13628: Support utf-8 encoded source files and latin-9 compatible identifiers. (Xavier Leroy and Florian Angeletti, review by Daniel Bünzli and Jules Aguillon)

• #12828, #13283: Add short syntax for dependent functor types (X:A) -> ... (Jeremy Yallop, review by Nicolás Ojeda Bär and Gabriel Scherer)

Type system

• #11891, #12507: Allow to name new locally abstract types in constructor type annotations. (Jacques Garrigue, report and review by Gabriel Scherer and Florian Angeletti)

Runtime system:

• #11911, #12923: Multicore statistical memory profiling. This restores a notable OCaml 4 feature that was missing in OCaml 5. (Nick Barnes, review by Stephen Dolan, Jacques-Henri Jourdan and Guillaume Munch-Maccagnoni).

• #13419: Fix memory bugs in runtime events system. (B. Szilvasy and Nick Barnes, review by Miod Vallat, Nick Barnes, Tim McGilchrist, and Gabriel Scherer)

• #13364: Emit major slice counters in the runtime events. (KC Sivaramakrishnan and Sadiq Jaffer, review by Gabriel Scherer)

• #13382: Add more documentation for Runtime_events types (Sadiq Jaffer, review by Tim McGilchrist, Miod Vallat and KC Sivaramakrishnan)

• #13370: Fix a low-probability crash when calling Gc.counters. (Demi Marie Obenour, review by Gabriel Scherer)

• #13272: Allow maximum number of domains to be specified as a OCAMLRUNPARAM parameter. (KC Sivaramakrishnan, review by Guillaume Munch-Maccagnoni, Miod Vallat, Gabriel Scherer, David Allsopp, request by Zachary Yedidia).

• #12579: OS-based Synchronisation for Stop-the-World Sections (B. Szilvasy, review by Miod Vallat, Nick Barnes, Olivier Nicole, Gabriel Scherer and Damien Doligez)

• #12789: Restore caml_unregister_frametable from OCaml 4 (Frédéric Recoules, review by Gabriel Scherer)

• #13003: new, more consistent names for array-creation C functions (Gabriel Scherer, review by Olivier Nicole)

• #13013: introduce a caml_result type to supersede the use of 'encoded exception values' in the FFI. (Gabriel Scherer, review by Damien Doligez, Guillaume Munch-Maccagnoni and Xavier Leroy, suggested by Guillaume Munch-Maccagnoni)

• #12407, #13226: Resource-handling improvements: add exception-returning variants for all exception-raising functions in caml/fail.h, for the purpose of cleaning-up state and resources before raising. (Guillaume Munch-Maccagnoni, review by Damien Doligez, Xavier Leroy and Gabriel Scherer)

• #13086: Avoid spurious major GC slices. (Damien Doligez, report by Stephen Dolan, review by Gabriel Scherer and Stephen Dolan)

• #11779, #13117: Improve logic for fiber stack alignment. (Miod Vallat, report by Damien Doligez, review by Gabriel Scherer)

• #12839: Remove ATOMIC_UINTNAT_INIT from camlatomic.h (as part of a larger cleanup of camlatomic.h) (David Allsopp, review by Antonin Décimo, Sébastien Hinderer, Samuel Hym, Guillaume Munch-Maccagnoni and Miod Vallat)

• #13163: Enable frame pointers on macOS x86_64 (Tim McGilchrist, review by Sébastien Hinderer and Fabrice Buoro)

• #12951: Constify constructors and flags tables in C code (take 2). Now these tables will go in the readonly segment, where they belong. (Antonin Décimo, review by David Allsopp)

• #10696: Introduce __has_attribute and __has_c_attributes in <caml/misc.h> to test the support of specific attributes in C code. Introduce fallthrough as a wrapper around the fallthrough attribute. (Antonin Décimo, review by Nicolás Ojeda Bär, Xavier Leroy, and Gabriel Scherer)

• #13083: Use macros from limits.h to avoid signed-integer wrap-around. Introduce CAML_{U,}INTNAT_{MIN,MAX} macros to expose {u,}intnat limits. (Antonin Décimo, review by Nick Barnes, Xavier Leroy, Gabriel Scherer, and Miod Vallat)

• #13239: Check whether the compiler supports the labels as values extension to enable threaded code interpretation. (Antonin Décimo, review by Miod Vallat)

• #13238: Enable software prefetching on x86 and x86_64 when building with MSVC or clang-cl. (Antonin Décimo, review by Miod Vallat)

• #13241, #13261, #13271: Add CFI_SIGNAL_FRAME to ARM64 and RiscV runtimes, for the purpose of displaying backtraces correctly in GDB. (Tim McGilchrist, review by Miod Vallat, Gabriel Scherer and KC Sivaramakrishnan)

• #13139: Simplify CAMLalign to always use C23/C++11 alignas or C11 _Alignas. Ensures that stat data is always aligned to the best boundary. (Antonin Décimo, review by Miod Vallat and Xavier Leroy)

• #13280: Check for support of compiler attributes. Allows using compiler attributes with clang-cl. (Antonin Décimo, review by Miod Vallat)

• #13243: Enable C compiler warnings internally when building with clang-cl or MSVC. Provide fixes too. (Antonin Décimo, review by Miod Vallat and Xavier Leroy)

• #13242: Define and use unreachable and trap annotation, and clean-up some runtime assertions. (Antonin Décimo, review by Miod Vallat, Gabriel Scherer, and David Allsopp)

• #13402, #13512, #13549, #13553: Revise bytecode implementation of callbacks so that it no longer produces dangling registered bytecode fragments. (Xavier Leroy, report by Jan Midtgaard, analysis by Stephen Dolan, review by Miod Vallat)

• #13407: Add Runtime_events.EV_EMPTY_MINOR (Thomas Leonard)

• #13522: Confirm runtime events ring is still active after callback. (KC Sivaramakrishnan, review by Sadiq Jaffer and Miod Vallat)

• #13529: Do not write to event ring after going out of stw participant set. (KC Sivaramakrishnan, review by Sadiq Jaffer)

Code generation and optimizations:

• #13014: Enable compile-time option -function-sections on all previously unsupported native backends (POWER, riscv64 and s390x) (Miod Vallat, review by Nicolás Ojeda Bär)

• #7241, #12555, #13076, #13138, #13338, #13152, #13153, #13154: fix a soundness bug in the pattern-matching compiler when side-effects mutate the scrutinee during matching. (Gabriel Scherer, review by Nick Roberts)

• #13341: a warning when the pattern-matching compiler pessimizes code because side-effects may mutate the scrutinee during matching. (This warning is disabled by default, as this rarely happens and its performance impact is typically not noticeable.) (Gabriel Scherer, review by Nick Roberts, Florian Angeletti and David Allsopp)

• #13179: Fix evaluation of toplevel lets in classes containing local opens (Vincent Laviron, review by Hugo Heuzard, Nathanaëlle Courant and Gabriel Scherer)

• #13543: Remove some String-Bytes conversion from the stdlib to behave better with js_of_ocaml (Hugo Heuzard, review by Gabriel Scherer)

Standard library:

• #12885: move Dynarray to an unboxed representation (Gabriel Scherer, suggestions by Vincent Laviron, review by Olivier Nicole and Simon Cruanes, Yann Leray, Alain Frisch)

• #12884: Add Queue.drop (Léo Andrès, review by Nicolás Ojeda Bär and Gabriel Scherer)

• #13168: In Array.shuffle, clarify the code that validates the result of the user-supplied function rand, and improve the error message that is produced when this result is invalid. (François Pottier, review by Florian Angeletti, Daniel Bünzli and Gabriel Scherer)

• #12133: Expose support for printing substrings in Format (Florian Angeletti, review by Daniel Bünzli, Gabriel Scherer and Nicolás Ojeda Bär)

• #12869: Add List.take, List.drop, List.take_while and List.drop_while (Kate Deplaix and Oscar Butler-Aldridge, review by Nicolás Ojeda Bär, Craig Ferguson and Gabriel Scherer)

• #13047: Add Sys.poll_actions to (only) run pending runtime actions. (Nick Barnes, review by Gabriel Scherer, Guillaume Munch-Maccagnoni, and Vincent Laviron)

• #13144: Dynarray.{equal, compare} (Gabriel Scherer, review by Jeremy Yallop, Daniel Bünzli and Olivier Nicole, request by Olivier Nicole)

• #13171: expose Domain.self_index : unit -> int (a somewhat-dense indexing of currently-running domains) for advanced use-cases of domain-indexed concurrent data structures. (Gabriel Scherer, review by KC Sivaramakrishnan, Miod Vallat and Nicolás Ojeda Bär, report by Vesa Karvonen)

• #13197: Dynarray.blit, which allows to extend the destination dynarray (0 <= dst_pos <= dst_length). (Gabriel Scherer, report by Hazem Elmasry, review by Olivier Nicole, Hazem Elmasry and Nicolás Ojeda Bär)

• (breaking change) #13240: Add Uchar.seeded_hash, Change Uchar.hash implementation. Previously, Uchar.hash was aliased to Uchar.to_int. If you need that behavior, change your module instantiation from eg module HT = Hashtbl.Make(Uchar) to

    module HT = Hashtbl.Make(struct
      ...
      let hash = Uchar.to_int
    end)
  

  If the current implementation is desired, and you have a hashtable module HT (produced with the Make functor) in persistent storage, use HT.rebuild to ensure it doesn't break when reading from or writing to buckets. (Hazem ElMasry, review by Gabriel Scherer and Nicolás Ojeda Bär)

• #13318: Fix regression in GC alarms, and fix them for flambda. (Guillaume Munch-Maccagnoni, report by Benjamin Monate, review by Vincent Laviron and Gabriel Scherer)

• #13296: Add mem, memq, find_opt, find_index, find_map and find_mapi to Dynarray. (Jake H, review by Gabriel Scherer and Florian Angeletti)

Other libraries:

• #11996: release the dependency of dynlink on compilerlibs. (Sébastien Hinderer and Stephen Dolan, review by Damien Doligez and Hugo Heuzard)

• #13326: Implement Unix.O_APPEND on windows. (Romain Beauxis, review by Miod Vallat, Gabriel Scherer and Antonin Décimo)

Tools:

• #11716: ocamllex: mismatched parentheses and curly brackets are now caught by ocamllex, instead of causing invalid OCaml code to be generated. (Demi Marie Obenour, review by Damien Doligez and Xavier Leroy)

• #12904: Run the testsuite with ThreadSanitizer on a PR when label run-thread-sanitizer is added (Olivier Nicole, suggested by Sébastien Hinderer and David Allsopp, review by Gabriel Scherer)

• (breaking change) #13114: Support ocamldebug remote debugging over IPv6 on all platforms, and over Unix domain sockets on Windows. (Antonin Décimo, review by Gabriel Scherer and Miod Vallat)

• #13136: Rewrite GDB extensions and macros in debugger-agnostic Python, and add LLDB support for them. (Nick Barnes, review by Tim McGilchrist and Gabriel Scherer)

Toplevel:

• #12891: Improved styling for initial prompt (Florian Angeletti, review by Gabriel Scherer)

• #13053: Improved display of builtin types such as _ list when aliased. (Samuel Vivien, review by Florian Angeletti)

Manual and documentation:

• #13370: Document that that temporary variables holding GCd pointers must not be live across a GC. (Demi Marie Obenour)

• #12298: Manual: emphasize that Bigarray.int refers to an OCaml integer, which does not match the C int type. (Edwin Török, review by Florian Angeletti)

• #12868: Manual: simplify style colours of the post-processed manual and API HTML pages, and fix the search button icon (Yawar Amin, review by Simon Grondin, Gabriel Scherer, and Florian Angeletti)

• #12949: document OCaml release cycles and version strings in release-info/introduction.md. (Florian Angeletti, review by Fabrice Buoro, Kate Deplaix, Damien Doligez, and Gabriel Scherer)

• #12976: Manual: use webman//*.html and webman//api/ for OCaml.org HTML manual generation (Shakthi Kannan, review by Hannes Mehnert, and Florian Angeletti)

• #13045: Emphasize caution about behaviour of custom block finalizers. (Nick Barnes)

• #13216: document the new caml_result type in the FFI chapter of the manual. (Gabriel Scherer, review by Miod Vallat, Daniel Bünzli, Nick Barnes, Guillaume Munch-Maccagnoni and Antonin Décimo)

• #13287: stdlib/sys.mli: Update documentation on Sys.opaque_identity following #9412. (Matt Walker, review by Guillaume Munch-Maccagnoni and Vincent Laviron)

• #13295: Use syntax for deep effect handlers in the effect handlers manual page. (KC Sivaramakrishnan, review by Anil Madhavapeddy, Florian Angeletti and Miod Vallat)

• #13424: Fix Gc.quick_stat documentation to clarify that returned fields live_words, live_blocks, free_words, and fragments are not zero. (Jan Midtgaard, review by Damien Doligez and KC Sivaramakrishnan)

• #13440: Update documentation of Gc.{control,get,set} to reflect fields not currently supported on OCaml 5. (Jan Midtgaard, review by Gabriel Scherer)

• #13469, #13474, #13535: Document that [Hashtbl.create n] creates a hash table with a default minimal size, even if [n] is very small or negative. (Antonin Décimo, Nick Bares, report by Nikolaus Huber and Jan Midtgaard, review by Florian Angeletti, Anil Madhavapeddy, Gabriel Scherer, and Miod Vallat)

• #13666: Rewrite parts of the example code around nested lists in Chapter 6 (Polymorphism and its limitations -> Polymorphic recursion) giving the "depth" function [in the non-polymorphically-recursive part of the example] a much more sensible behavior; also fix a typo and some formatting. (Frank Steffahn, review by Florian Angeletti)

• #13668: Document the basic support for unicode identifiers and the switch to UTF-8 encoded Unicode text for OCaml source file (Florian Angeletti, review by Nicolás Ojeda Bär and Daniel Bünzli)

Compiler user-interface and warnings:

• (breaking change) #12084, #13669, #13673: Check link order when creating archive and when using ocamlopt. (Hugo Heuzard, review by Stefan Muenzel and Sébastien Hinderer)

• #12980: Explain type mismatch involving first-class modules by including the module level error message (Florian Angeletti, review by Vincent Laviron)

• #12985, #12988: Better error messages for partially applied functors. (Florian Angeletti, report by Arthur Wendling, review by Gabriel Scherer)

• #13034, #13260: Better error messages for mismatched function labels (Florian Angeletti, report by Daniel Bünzli, review by Gabriel Scherer and Samuel Vivien)

• #13051: Add a "Syntax error" to error messages for invalid package signatures. (Samuel Vivien, review by Gabriel Scherer)

• #13099: Fix erroneous loading of cmis for some module type errors. (Nick Roberts, review by Florian Angeletti)

• #13151, name conflicts explanation as a footnote (Florian Angeletti, review by Gabriel Scherer)

• #13228: Re-export Cmt2annot.{iterator,binary_part} which had become hidden since #11288 and broke ocamlbrowser. (David Allsopp, report by Jacques Garrigue, review by Sébastien Hinderer)

• #13251: Register printer for errors in Emitaux (Vincent Laviron, review by Miod Vallat and Florian Angeletti)

• #13255: Re-enable warning 34 for unused locally abstract types (Nick Roberts, review by Chris Casinghino and Florian Angeletti)

• #12182: Improve the type clash error message. For example, this message: This expression has type ... is changed into: The constant "42" has type ... (Jules Aguillon, review by Gabriel Scherer and Florian Angeletti)

• #13471: add -keywords <version?+list> flag to define the list of keywords recognized by the lexer, for instance -keywords 5.2 disable the effect keyword. (Florian Angeletti, review by Gabriel Scherer)

Internal/compiler-libs changes:

• #13286: Distinguish unique identifiers Shape.Uid.t according to their provenance: either an implementation or an interface. (Ulysse Gérard, review by Florian Angeletti and Leo White)

• #13308: keep track of relations between declaration in the cmt files. This is useful information for external tools for navigation and analysis purposis. (Ulysse Gérard, Florian Angeletti, review by Florian Angeletti and Gabriel Scherer)

• #11129, #11148: enforce that ppxs do not produce parsetrees with an empty list of universally quantified type variables (. int -> int instead of 'a . int -> int') (Florian Angeletti, report by Simmo Saan, review by Gabriel Scherer)

• #12534: document and refactor Matching.mk_failaction_pos (Gabriel Scherer, review by Vincent Laviron and Nick Roberts)

• #13076: change the handling of Match_failure exits in the pattern-matching compiler, to prepare for a complete fix for #7241 (Gabriel Scherer, review by Thomas Refis and Nick Roberts)

• #12896: Simplify the compilation of custom bytecode runtimes by explicitly compiling the primitives file before calling the linker. Tidy-up both the generating code and the output itself for C code being generated by the bytecode linker in -custom and -output-* modes. (David Allsopp, Antonin Décimo and Samuel Hym, review by Vincent Laviron)

• #12932: Remove useless code in Typecore.type_label_exp (was a fix for #4862) (Jacques Garrigue, review by Gabriel Scherer)

• #12943: Make transient_expr.scope a bitfield, and use it to store marks. Marks are automatically allocated, and removed when leaving their scope. Falls back to using TransientTypeSet when marks are exhausted. (Jacques Garrigue and Takafumi Saikawa, review by Basile Clément)

• #12946: Make generalization automatic when leaving scope. As a result, the Ctype.generalize* and Ctype.correct_levels functions were removed. The latter is now called Ctype.duplicate_type. (Jacques Garrigue and Takafumi Saikawa, review by Richard Eisenberg)

• #12968: Attach location to constants in the parsetree (Jules Aguillon, review by Gabriel Scherer)

• #12959, #13055: Avoid an internal error on recursive module type inconsistency (Florian Angeletti, review by Jacques Garrigue and Gabriel Scherer)

• #13049: graphical debugging printer for types (Florian Angeletti, review by Gabriel Scherer)

• #13074, #13082, #13084: refactoring in the pattern-matching compiler (Gabriel Scherer, review by Thomas Refis, Vincent Laviron and Nick Roberts)

• #13067: rework volatile memory access rules under TSan to consider properly aligned smaller-than-register read operations as atomic, which gets rid of false positives on s390x (Miod Vallat, review by Fabien Buoro)

• #13162: Use quoted strings to clarify code being generated. (Antonin Décimo, review by Miod Vallat and Gabriel Scherer)

• #13015: Emit floating-point literals in .rodata section on ELF arm64 platforms (Linux, *BSD). (Miod Vallat, review by Nicolás Ojeda Bär)

• #13169, #13311: Introduce a document data type for compiler messages rather than relying on Format.formatter -> unit closures. (Florian Angeletti, review by Gabriel Scherer)

• #13193: Remove the unused env_init field from class blocks (Vincent Laviron, review by Jacques Garrigue)

• #13257: integrate MetaOCaml in the Menhir grammar to ease MetaOCaml maintenance. This is a purely internal change: there is no support in the lexer, so no change to the surface OCaml grammar. (Oleg Kiselyov, Gabriel Scherer and Florian Angeletti, review by Jeremy Yallop)

• #13289: Use C99 for loop to reduce the scope of the for loop iterator. (Antonin Décimo, review by Miod Vallat and Gabriel Scherer)

• #13336: compiler-libs, split the Printtyp in three to only keep "user-friendly" functions in the Printtyp module. (Florian Angeletti, review by Gabriel Scherer)

• #13361: split runtime/array.c functions to consistently expose uniform_array and floatarray versions, use floatarray versions in Float.Array. (Gabriel Scherer, review by Nicolás Ojeda Bär)

• #13507: A small refactoring to [free_vars] to make it a bit faster by not allocating a list when the list is not necessary. (Richard Eisenberg, review by Jacques Garrigue)

Build system:

• #12909: Reorganise how MKEXE_VIA_CC is built to make it correct for MSVC by grouping all the linker flags at the end of the C compiler commandline (David Allsopp and Samuel Hym, review by Nicolás Ojeda Bär)

• #12992, #13009: Check that flexlink can be executed only when building in a native windows environment. (Romain Beauxis, review by David Allsopp and Sébastien Hinderer)

• #12996: Only link with -lgcc_eh when available. (Romain Beauxis, review by David Allsopp and Miod Vallat)

• (breaking change) #13200: Do not use CFLAGS for linking. (Sébastien Hinderer, review by Gabriel Scherer, Antonin Décimo, Miod Vallat and Samuel Hym)

• #13201, #13244: Fix and speedup builds with TSan. (Sébastien Hinderer, review by Miod Vallat, Gabriel Scherer and Olivier Nicole)

• (breaking change) #12578, #12589, #13322, #13519: Use configured CFLAGS and CPPFLAGS only during the build of the compiler itself. Do not use them when compiling third-party C sources through the compiler. Flags for compiling third-party C sources can still be specified at configure time in the COMPILER_{BYTECODE,NATIVE}_{CFLAGS,CPPFLAGS} configuration variables. (Sébastien Hinderer, report by William Hu, review by David Allsopp)

• #13285: continue the merge of the sub-makefiles into the root Makefile started with #11243, #11248, #11268, #11420, #11675, #12198, #12321, #12586, #12616, #12706 and #13048. (Sébastien Hinderer, review by David Allsopp and Florian Angeletti)

Bug fixes:

• #12854: Add a test in the regression suite that flags the bug #12825. (Luc Maranget)

• #12888: fix printing of uncaught exceptions in .cmo files passed on the command-line of the toplevel. (Nicolás Ojeda Bär, review by Florian Angeletti, report by Daniel Bünzli)

• #12910, #12920: Fix an unsound interaction between first-class modules and polymorphic records by saving and restoring univar_pairs. (Stephen Dolan, review by Gabriel Scherer, report by Jeremy Yallop)

• #12994: Remove un-used and unsafe caml_drop_continuation (Tim McGilchrist, reviewed by Gabriel Scherer and Miod Vallat)

• #12963: Restore caml_runtime_parameters implementation. This primitive allows programs to query the runtime parameters supplied to an OCaml program. Implementation missing since OCaml 5.0. (Tim McGilchrist, reviewed by David Allsopp and Miod Vallat)

• #13012: parsing: Fix dropped attributes after a '-' or '+' The syntax '-(1 [@foo])' was incorrectly parsed as '-1'. (Jules Aguillon, reviewed by Gabriel Scherer, report by Gabriel Scherer)

• (breaking change) #13070: On Windows, when configured with bootstrapped flexdll, don't add +flexdll to the search path when -nostdlib is specified (which then means -L no longer gets passed to the system linker). (David Allsopp, review by Florian Angeletti)

• #13089: Fix bug in runtime_events library which could result in garbled output under Windows. (B. Szilvasy, review by Nicolás Ojeda Bär and Miod Vallat)

• #13088: A few type-checker behaviors look at a type to see if there are any labeled arguments in it. This sometimes required expansion, which could, in obscure scenarios, result in superfluous type errors. (Richard Eisenberg, review by Gabriel Scherer and Jacques Garrigue)

• #13103: FreeBSD/amd64: properly annotate .o files with non-executable stack notes (Konstantin Belousov, review by Nicolás Ojeda Bär)

• #13150: improve a transitive-closure computation algorithm in the flambda middle-end to avoid a compilation time blowup on Menhir-generated code (Florian Weimer, review by Gabriel Scherer and Pierre Chambart, report by Richard Jones)

• #13166: Fix a MinGW/MSVC Sys.rename regression on renaming a parent directory to an empty child directory. (Jan Midtgaard, review by Antonin Décimo, Sébastien Hinderer, and David Allsopp)

• #13185, #13192: Reject type-level module aliases on functor parameter inside signatures. (Jacques Garrigue, report by Richard Eisenberg, review by Florian Angeletti)

• #13170: Fix a bug that would result in some floating alerts [@@@alert ...] incorrectly triggering Warning 53. (Nicolás Ojeda Bär, review by Chris Casinghino and Florian Angeletti)

• #13203: Do not issue warning 53 if the compiler is stopping before attributes have been accurately marked. (Chris Casinghino, review by Florian Angeletti)

• #13207: Be sure to reload the register caching the exception handler in caml_c_call and caml_c_call_stack_args, as its value may have been changed if the OCaml stack is expanded during a callback. (Miod Vallat, report by Vesa Karvonen, review by Gabriel Scherer and Xavier Leroy)

• #13209: Fix configure test that checks whether ar supports @FILE arguments. (Nicolás Ojeda Bär, report by Boris D.)

• #13221: Compute more accurate instruction sizes for branch relocation on POWER. (Miod Vallat, review by Gabriel Scherer)

• #13252: Rework register assignment in the interpreter code on m68k on Linux, due to the %a5 register being used by Glibc. (Miod Vallat, report by Stéphane Glondu, review by Gabriel Scherer and Xavier Leroy)

• #13247: Disable lib_unix/kill test for MacOS AMD64 with TSan, linking to llvm bug report causing infinite signal loops. (Tim McGilchrist, review by Olivier Nicole, Miod Vallat, Sébastien Hinderer and Gabriel Scherer)

• #13234, #13267: Open runtime events file in read-write mode on armel (armv5) systems due to atomic operations limitations on that platform. (Stéphane Glondu, review by Miod Vallat and Vincent Laviron)

• #13273: Fix a call to test in configure.ac that was causing errors when LDFLAGS contains several words. (Stéphane Glondu, review by Miod Vallat)

• #13290: Fix uninitialized and out of bounds reads in runtime_events_consumer.c (Edwin Török, review by Miod Vallat and Antonin Décimo)

• #13306: An algorithm in the type-checker that checks two types for equality could sometimes, in theory, return the wrong answer. This patch fixes the oversight. No known program triggers the bug. (Richard Eisenberg, review by Florian Angeletti)

• #13400: Initialize th->signal_stack to avoid free of uninitialized data if the user calls caml_c_thread_unregister on the main thread. (Richard W.M. Jones, review by Guillaume Munch-Maccagnoni and Gabriel Scherer)

• #13140: POWER back-end: fix issue with call to caml_call_realloc_stack from a DLL (Xavier Leroy, review by Miod Vallat)

• #13263, #13560: fix printing true and false in toplevel and error messages (no more unexpected #true) (Florian Angeletti, report by Samuel Vivien, review by Gabriel Scherer)

• #13388, #13540: raises an error message (and not an internal compiler error) when two local substitutions are incompatible (for instance module type S:=sig end type t:=(module S)) (Florian Angeletti, report by Nailen Matschke, review by Gabriel Scherer, and Leo White)

• #13408: Fix misplaced debug runtime assertion triggerable by a race between domain exit and backup thread (Miod Vallat and Gabriel Scherer, report by Jan Midtgaard)

• #13417: Filename.quote_command: fix handling of forward slashes in program path under Win32. (Nicolás Ojeda Bär, review by David Allsopp and Damien Doligez)

• #13501: Regression on mutually recursive types caused by #12180. Resuscitate Typedecl.update_type. (Jacques Garrigue and Takafumi Saikawa, review by Florian Angeletti, Richard Eisenberg and Gabriel Scherer)

• #13502: Fix misindexing related to Gc.finalise_last that could prevent finalisers from being run. (Nick Roberts, review by Mark Shinwell)

• #13495, #13514: Fix typechecker crash while typing objects (Jacques Garrigue, report by Nicolás Ojeda Bär, review by Nicolas Ojeda Bär, Gabriel Scherer, Stephen Dolan, Florian Angeletti)

• #13391, #13551: fix a printing bug with -dsource when using raw literal inside a locally abstract type constraint (i.e. let f: type \#for. ... ) (Florian Angeletti, report by Nick Roberts, review by Richard Eisenberg)

• #13520: Fix compilation of native-code version of systhreads. Bytecode fields were being included in the thread descriptors. (David Allsopp, review by Sébastien Hinderer and Miod Vallat)

• #13541, #13591: Fix headers for C++ inclusion. (Antonin Décimo, review by Nick Barnes, report by Kate Deplaix)

• #13579, #13583: Unsoundness involving non-injective types + gadts (Jacques Garrigue, report by @v-gb, review by Richard Eisenberg and Florian Angeletti)

• #13598: Falsely triggered warning 56 [unreachable-case] This was caused by unproper protection of the retyping function. (Jacques Garrigue, report by Tõivo Leedjärv, review by Florian Angeletti)

• #13603, #13604: fix source printing in the presence of the escaped raw identifier \#mod. (Florian Angeletti, report by Chris Casinghino, review by Gabriel Scherer)

Features

• Add custom ocamllsp/typeSearch request (#1369)
• Make MerlinJump code action configurable (#1376)
• Add custom ocamllsp/jump request (#1374)

Fixes

• Deactivate the jump code actions by default. Clients can enable them with the merlinJumpCodeActions configuration option. Alternatively, a custom request is provided for ad hoc use of the feature. (#1411)
• Fix FD leak in running external processes for preprocessing (#1349)
• Fix prefix parsing for completion of object methods (#1363, fixes #1358)
• Remove some duplicates in the selectionRange answers (#1368)

• merlin binary

  • Respect the EXCLUDE_QUERY_DIR configuration directive when looking for cmt files #1854
  • Fix exception in polarity search (#1858 fixes #1113)
  • Fix type-enclosing results instability. This reverts some overly aggressive deduplication that should be done on the client side. #1864

• merlin binary (only in 5.3-502)

  • Fix occurrences bug in which relative paths in index files are resolved against the PWD rather than the SOURCE_ROOT #1855
  • Fix jump to fun targets not working (#1863, fixes #1862)
  • Fix occurrences not working when the definition comes from a hidden source file #1865

Fixed

• When a library declares (no_dynlink), then the .cmxs file for it is no longer built. (#11176, @nojb)

• Fix bug that could result in corrupted file copies by Dune, for example when using the copy_files# stanza or the copy# action. (@nojb, #11194, fixes #11193)

• Remove useless error message when running $ dune subst in empty projects. (@rgrinberg, #11204, fixes #11200)

• Add a new --pre-release argument adding the necessary flags and availibility formula for pre-releases [#164 @kit-ty-kate]

Added

• OCaml 5.3.0 compatibility (@Julow, #1202, #1254)

Highlight

• * Support OCaml 5.2 syntax (#2519, #2544, #2590, #2596, #2621, #2628, @Julow, @EmileTrotignon, @hhugo) This includes local open in types, raw identifiers, and the new representation for functions. This might change the formatting of some functions due to the formatting code being completely rewritten.

• Support OCaml 5.3 syntax (#2609, #2610, #2611, #2622, #2623, #2562, #2624, #2625, #2627, @Julow, @Zeta611) This adds support for effect patterns, short functor type arguments and utf8 identifiers. To format code using the new effect syntax, add this option to your .ocamlformat:

  ocaml-version = 5.3
  

• Documentation comments are now formatted by default (#2390, @Julow) Use the option parse-docstrings = false to restore the previous behavior.

• * Consistent indentation of polymorphic variant arguments (#2427, @Julow) Increases the indentation by one to make the formatting consistent with normal variants. For example:

    ...
    (* before *)
      (`Msg
        (foo bar))
    (* after *)
      (`Msg
         (foo bar))
  

• Build on OCaml 5.3 (#2603, @adamchol, @Julow)

Added

• Improve the emacs plugin (#2577, #2600, @gridbugs, @thibautbenjamin) Allow a custom command to be used to run ocamlformat and add compatibility with emacs ocaml tree-sitter modes.

• Added option let-binding-deindent-fun (#2521, @henrytill) to control the indentation of the fun in:

  let f =
   fun foo ->
    bar
  

• Added back the flag --disable-outside-detected-project (#2439, @gpetiot) It was removed in version 0.22.

• Support newer Odoc syntax (#2631, #2632, #2633, @Julow)

Changed

• * Consistent formatting of comments (#2371, #2550, @Julow) This is mostly an internal change but some comments might be formatted differently.

• * Improve formatting of type constraints with type variables (#2437, @gpetiot) For example:

  let f : type a b c.
      a -> b -> c =
    ...
  

• * Improve formatting of functor arguments (#2505, @Julow) This also reduce the indentation of functor arguments with long signatures.

• Improvements to the Janestreet profile (#2445, #2314, #2460, #2593, #2612, @Julow, @tdelvecchio-jsc)

• * Undo let-bindings and methods normalizations (#2523, #2529, @gpetiot) This remove the rewriting of some forms of let-bindings and methods:

  • let f x = (x : int) is no longer rewritten into let f x : int = x
  • let f (type a) (type b) ... is no longer rewritten into let f (type a b) ...
  • let f = fun x -> ... is no longer rewritten into let f x = ...

• * The break-colon option is now taken into account for method type constraints (#2529, @gpetiot)

• * Force a break around comments following an infix operator (fix non-stabilizing comments) (#2478, @gpetiot) This adds a line break:

    a
    ||
    (* this comment is now on its own line *)
    b
  

Fixed

• Fix placement of comments in some cases (#2471, #2503, #2506, #2540, #2541, #2592, #2617, @gpetiot, @Julow) Some comments were being moved or causing OCamlformat to crash. OCamlformat refuses to format if a comment would be missing in its output, to avoid loosing code.
• Fix attributes being dropped or moved (#2247, #2459, #2551, #2564, #2602, @EmileTrotignon, @tdelvecchio-jsc, @Julow) OCamlformat refuses to format if the formatted code has a different meaning than the original code, for example, if an attribute is removed. We also try to avoid moving attributes even if that doesn't change the original code, for example we no longer format open[@attr] M as open M [@@attr].
• Remove trailing space inside a wrapping empty signature (#2443, @Julow)
• Fix extension-point spacing in structures (#2450, @Julow)
• * Consistent break after string constant argument (#2453, @Julow)
• * Fix cinaps comment formatting to not change multiline string contents (#2463, @tdelvecchio-jsc)
• * Fix the indentation of tuples in attributes and extensions (#2488, @Julow)
• * Fix weird indentation and line breaks after comments (#2507, #2589, #2606, @Julow)
• * Fix unwanted alignment in if-then-else (#2511, @Julow)
• Fix missing parentheses around constraint expressions with attributes (#2513, @alanechang)
• Fix formatting of type vars in GADT constructors (#2518, @Julow)
• Fix [@ocamlformat "disable"] in some cases (#2242, #2525, @EmileTrotignon) This caused a bug inside class type constructs and when attached to a let ... in
• Display a##b instead of a ## b and similarly for operators that start with # (#2580, @v-gb)
• * Fix arrow type indentation with break-separators=before (#2598, @Julow)
• Fix missing parentheses around a let in class expressions (#2599, @Julow)
• Fix formatting of paragraphs in lists in documentation (#2607, @Julow)
• Avoid unwanted space in references and links text in documentation (#2608, @Julow)
• * Improve the indentation of attributes in patterns (#2613, @Julow)
• * Avoid large indentation in patterns after let%ext (#2615, @Julow)

Fixed

• Show the context name for errors happening in non-default contexts. (#10414, fixes #10378, @jchavarri)

• Correctly declare dependencies of indexes so that they are rebuilt when needed. (#10623, @voodoos)

• Don't depend on coq-stdlib being installed when expanding variables of the coq.version family (#10631, fixes #10629, @gares)

• Error out if no files are found when using copy_files. (#10649, @jchavarri)

• Re_export dune-section private library in the dune-site library stanza, in order to avoid failure when generating and building sites modules with implicit_transitive_deps = false. (#10650, fixes #9661, @MA0100)

• Expect test fixes: support multiple modes and fix dependencies when there is a custom runner (#10671, @vouillon)

• In a (library) stanza with (extra_objects) and (foreign_stubs), avoid double linking the extra object files in the final executable. (#10783, fixes #10785, @nojb)

• Map (re_export) library dependencies to the exports field in META files, and vice-versa. This field was proposed in to https://discuss.ocaml.org/t/proposal-a-new-exports-field-in-findlib-meta-files/13947. The field is included in Dune-generated META files only when the Dune lang version is >= 3.17. (#10831, fixes #10830, @nojb)

• Fix staged pps preprocessors on Windows (which were not working at all previously) (#10869, fixes #10867, @nojb)

• Fix dune describe when an executable is disabled with enabled_if. (#10881, fixes #10779, @moyodiallo)

• Fix an issue where C stubs would be rebuilt whenever the stderr of Dune was redirected. (#10883, fixes #10882, @nojb)

• Fix the URL opened by the command dune ocaml doc. (#10897, @gridbugs)

• Fix the file referred to in the error/warning message displayed due to the dune configuration version not supporting a particular configuration stanza in use. (#10923, @H-ANSEN)

• Fix enabled_if when it uses env variable. (#10936, fixes #10905, @moyodiallo)

• Fix exec -w for relative paths with --root argument (#10982, @gridbugs)

• Do not ignore the (locks ..) field in the test and tests stanza (#11081, @rgrinberg)

• Tolerate files without extension when generating merlin rules. (#11128, @anmonteiro)

Added

• Make Merlin/OCaml-LSP aware of "hidden" dependencies used by (implicit_transitive_deps false) via the -H compiler flag. (#10535, @voodoos)

• Add support for the -H flag (introduced in OCaml compiler 5.2) in dune (requires lang versions 3.17). This adaptation gives the correct semantics for (implicit_transitive_deps false). (#10644, fixes #9333, ocsigen/tyxml#274, #2733, #4963, @MA0100)

• Add support for specifying Gitlab organization repositories in source stanzas (#10766, fixes #6723, @H-ANSEN)

• New option to control jsoo sourcemap generation in env and executable stanza (#10777, fixes #10673, @hhugo)

• One can now control jsoo compilation_mode inside an executable stanza (#10777, fixes #10673, @hhugo)

• Add support for specifying default values of the authors, maintainers, and license stanzas of the dune-project file via the dune config file. Default values are set using the (project_defaults) stanza (#10835, @H-ANSEN)

• Add names to source tree events in performance traces (#10884, @jchavarri)

• Add codeberg as an option for defining project sources in dune-project files. For example, (source (codeberg user/repo)). (#10904, @nlordell)

• dune runtest can now run individual tests with dune runtest mytest.t (#11041, @Alizter).

• Wasm_of_ocaml support (#11093, @vouillon)

• Add a coqdep_flags field to the coq field of the env stanza, and to the coq.theory stanza, allowing to configure coqdep flags. (#11094, @rlepigre)

Changed

• Remove all remnants of the experimental patch-back-source-tree. (#10771, @rgrinberg)

• Change the preset value for author and maintainer fields in the dune-project file to encourage including emails. (#10848, @punchagan)

• Tweak the preset value for tags in the dune-project file to hint at topics not having a special meaning. (#10849, @punchagan)

• Change some colors to improve readability in light-mode terminals (#10890, @gridbugs)

• Forward the linkall flag to jsoo in whole program compilation as well (#10935, @hhugo)

• Configurator uses pkgconf as pkg-config implementation when available and forwards it the target of ocamlc -config. (#10937, @pirbo)

• Enable Dune cache by default. Add a new Dune cache setting enabled-except-user-rules, which enables the Dune cache, but excludes user-written rules from it. This is a conservative choice that can avoid breaking rules whose dependencies are not correctly specified. This is the current default. (#10944, #10710, @nojb, @ElectreAAS)

• Do not add dune dependency in dune-project when creating projects with dune init proj. The Dune dependency is implicitely added when generating opam files (#11129, @Leonidas-from-XIV)

Changes Since OCaml 5.2.0

Runtime System:

• #13207: Be sure to reload the register caching the exception handler in caml_c_call and caml_c_call_stack_args, as its value may have been changed if the OCaml stack is expanded during a callback. (Miod Vallat, report by Vesa Karvonen, review by Gabriel Scherer and Xavier Leroy)

• #13252: Rework register assignment in the interpreter code on m68k on Linux, due to the %a5 register being used by GLIBC. (Miod Vallat, report by Stéphane Glondu, review by Gabriel Scherer and Xavier Leroy)

• #13268: Fix a call to test in configure.ac that was causing errors when LDFLAGS contains several words. (Stéphane Glondu, review by Miod Vallat)

• #13234, #13267: Open runtime events file in read-write mode on ARMel (ARMv5) systems due to atomic operations limitations on that platform. (Stéphane Glondu, review by Miod Vallat and Vincent Laviron)

• #13188: fix races in the FFI code coming from the use of Int_val(...) on rooted values inside blocking questions / without the runtime lock. (Calling Int_val(...) on non-rooted immediates is fine, but any access to rooted values must be done outside blocking sections / with the runtime lock.) (Etienne Millon, review by Gabriel Scherer, Jan Midtgaard, Olivier Nicole)

• #13318: Fix regression in GC alarms, and fix them for Flambda. (Guillaume Munch-Maccagnoni, report by Benjamin Monate, review by Vincent Laviron and Gabriel Scherer)

• #13140: POWER back-end: fix issue with call to caml_call_realloc_stack from a DLL (Xavier Leroy, review by Miod Vallat)

• #13370: Fix a low-probability crash when calling Gc.counters. (Demi Marie Obenour, review by Gabriel Scherer)

• #13402, #13512, #13549, #13553: Revise bytecode implementation of callbacks so that it no longer produces dangling registered bytecode fragments. (Xavier Leroy, report by Jan Midtgaard, analysis by Stephen Dolan, review by Miod Vallat)

• #13502: Fix misindexing related to Gc.finalise_last that could prevent finalisers from being run. (Nick Roberts, review by Mark Shinwell)

• #13520: Fix compilation of native-code version of systhreads. Bytecode fields were being included in the thread descriptors. (David Allsopp, review by Sébastien Hinderer and Miod Vallat)

Fixed

• Call the C++ compiler with -std=gnu++11 when using OCaml >= 5.0 (#10962, @kit-ty-kate)

  Added

• merlin binary
  • A new WRAPPING_PREFIX configuration directive that can be used to tell Merlin what to append to the current unit name in the presence of wrapping (ocaml/merlin#1788)
  • Add -unboxed-types and -no-unboxed-types as OCaml ignored flags (ocaml/merlin#1795, fixes ocaml/merlin#1794)
  • Destruct: Refinement in the presence of optional arguments (ocaml/merlin#1800 ocaml/merlin#1807, fixes ocaml/merlin#1770)
  • Implement new expand-node command for expanding PPX annotations (ocaml/merlin#1745)
  • Implement new inlay-hints command for adding hints on a source tree (ocaml/merlin#1812)
  • Implement new search-by-type command for searching values by types (ocaml/merlin#1828)
  • Canonicalise paths in occurrences. This helps deduplicate the results and
  • Show more user-friendly paths. (ocaml/merlin#1840)
  • Fix dot-merlin-reader ignoring SOURCE_ROOT and STDLIB directives (ocaml/merlin#1839, ocaml/merlin#1803)
• editor modes
  • Vim:
    • Fix Python-3.12 syntax warnings in merlin.py (ocaml/merlin#1798)
    • Dead code / doc removal for previously deleted MerlinPhrase command (ocaml/merlin#1804)
  • Emacs:
    • Improve the way that result of polarity search is displayed (#1814)
    • Add merlin-search-by-type, merlin-search-by-polarity and change the behaviour of merlin-search to switch between by-type or by-polarity depending on the query (ocaml/merlin#1828)

Fixed

• Fix missing katex headers (@panglesd, #1096)
• Allow ][ in code blocks, fixing issue #1137 (@Julow, #1149)
  This was interpreted as "code blocks with result", which now mandates a
  delimiter: {delim@lang[ code ]delim[ result ]}
• Fix misprinting of type variables from ml files for OCaml 4.14 and later
  (multiple occurences of the same type variable could be named differently)
  (@Octachron, #1173)

• Add --exclude to exclude the given packages from the publishing process [#161 @kit-ty-kate]

Features

• Add custom ocamllsp/getDocumentation request (ocaml/ocaml-lsp#1336)
• Add support for OCaml 5.2 (ocaml/ocaml-lsp#1233)

Fixes

• Kill unnecessary OCamlFormat processes with sigterm rather than sigint or sigkill (ocaml/ocaml-lsp#1343)

• Fix a bug where Code_path.main_module_name would not properly remove extensions from the filename and therefore return an invalid module name. (#512, @NathanReb)

• Add -unused-type-warnings flag to the driver to allow users to disable only the generation of Warning 34 silencing structure items when using [@@deriving ...] on type declarations. (#511, @mbarbin, @NathanReb)

• Make the -unused-code-warnings driver flag also control Warning 34 silencing for type declarations with [@@deriving ...] attached. (#510, @mbarbin, @NathanReb)

• Add -unused-code-warnings=force driver command-line flag argument. (#490, @mbarbin)

• Add new functions Ast_builder.{e,p}list_tail that take an extra tail expression/pattern argument parameter compared to Ast_builder.{e,p}list, so they can build ASTs like a :: b :: c instead of only [ a; b ]. (#498, #502, @v-gb, @NathanReb)

• Fix Longident.parse so it also handles indexing operators such as .!(), .%(;..)<-, or Vec.(.%()) (#494, @octachron)

• Add a special_function' variant that directly takes a Longident.t argument in order to avoid the issue with Longident.t covering distinct syntactic classes that cannot be easily parsed by a common parser (#496, @octachron).

• Keep location ranges consistent when migrating Pexp_function nodes from 5.2+ to older versions (#504, @jchavarri)

• Fix -locations-check behaviour so it is no longer required to pass -check and can enable location checks. (#506, @NathanReb)

Features

• Introduce a configuration option to control Dune diagnostics. The option is called duneDiganostics, and it may be set to { enable: false } to disable diagnostics. (ocaml/ocaml-lsp#1221)

• Support folding of ifthenelse expressions (ocaml/ocaml-lsp#1031)

• Improve hover behavior (ocaml/ocaml-lsp#1245)

  Hovers are no longer displayed on useless parse tree nodes such as keywords, comments, etc.

  Multiline hovers are now filtered away.

  Display expanded PPXs in the hover window.

• Improve document symbols (ocaml/ocaml-lsp#1247)

  Use the parse tree instead of the typed tree. This means that document symbols will work even if the source code doesn't type check.

  Include symbols at arbitrary depth.

  Differentiate functions / types / variants / etc.

  This now includes PPXs like let%expect_test or let%bench in the outline.

• Introduce a destruct-line code action. This is an improved version of the old destruct code action. (ocaml/ocaml-lsp#1283)

• Improve signature inference to only include types for elements that were absent from the signature. Previously, all signature items would always be inserted. (ocaml/ocaml-lsp#1289)

• Add an update-signature code action to update the types of elements that were already present in the signature (ocaml/ocaml-lsp#1289)

• Add custom ocamllsp/merlinCallCompatible request (ocaml/ocaml-lsp#1265)

• Add custom ocamllsp/typeEnclosing request (ocaml/ocaml-lsp#1304)

Fixes

• Detect document kind by looking at Merlin's suffixes config.

  This enables more LSP features for non-.ml/.mli files. Though it still depends on Merlin's support. (ocaml/ocaml-lsp#1237)

• Correctly accept the --clientProcessId flag. (ocaml/ocaml-lsp#1242)

• Disable automatic completion and signature help inside comments (ocaml/ocaml-lsp#1246)

• Includes a new optional/configurable option to toggle syntax documentation. If toggled on, allows display of syntax documentation on hover tooltips. Can be controlled via environment variables and by GUI for VS code. (ocaml/ocaml-lsp#1218)

• For completions on labels that the LSP gets from Merlin, take into account whether the prefix being completed starts with ~ or ?. Change the label completions that start with ? to start with ~ when the prefix being completed starts with ~. (ocaml/ocaml-lsp#1277)

• Fix document syncing (ocaml/ocaml-lsp#1278, ocaml/ocaml-lsp#1280, fixes ocaml/ocaml-lsp#1207)

• Stop generating inlay hints on generated code (ocaml/ocaml-lsp#1290)

• Fix parenthesising of function types in SignatureHelp (ocaml/ocaml-lsp#1296)

• Fix syntax documentation rendering (ocaml/ocaml-lsp#1318)

• Adapt to opam 2.2 API and update lower bound to opam libs [#138 @kit-ty-kate]
• Use opam download command mechanism to select a specific download command [#159 @Emilios1995]

• merlin binary
  • Support project-wide occurrences queries using index files (ocaml/merlin#1766)
    • The file format is described in library Merlin_lib.index_format
    • Two new configuration directives are introduced:
      • SOURCE_ROOT that is used to resolve relative paths found in the indexes.
      • INDEX that is used to declare the list of index files Merlin should use when looking for occurrences.
  • A new UNIT_NAME configuration directive that can be used to tell Merlin the correct name of the current unit in the presence of wrapping (ocaml/merlin#1776)
  • Perform incremental indexation of the buffer when typing. (ocaml/merlin#1777)
  • merlin-lib.commands: Add a find_command_opt alternative to find_command that does not raise (ocaml/merlin#1778)
  • Prevent uid clashes by not returning PWO for defs located in the current interface file (ocaml/merlin#1781)
  • Reset uid counters when restoring the typer cache so that uids are stable across re-typing (ocaml/merlin#1779)
  • Improve the behavior on occurrences when the cursor is on a label / constructor declaration (ocaml/merlin#1785)
• editor modes
  • emacs: add basic support for project-wide occurrences (ocaml/merlin#1766)
  • vim: add basic support for project-wide occurrences (ocaml/merlin#1767, @Julow)

Added

• Allow libraries with the same (name ..) in projects as long as they don't conflict during resolution (via enabled_if). (#10307, @anmonteiro, @jchavarri)

• dune describe pp now finds the exact module and the stanza it belongs to, instead of guessing the name of the preprocessed file. (#10321, @anmonteiro)

• Print the result of dune describe pp with the respective dialect printer. (#10322, @anmonteiro)

• Add new flag --context to dune ocaml-merlin, which allows to select a Dune context when requesting Merlin config. Add dune describe contexts subcommand. Introduce a field generate_merlin_rules for contexts declared in the workspace, that allows to optionally produce Merlin rules for other contexts besides the one selected for Merlin (#10324, @jchavarri)

• Melange: add include paths for private library .cmj files during JS emission. (#10416, @anmonteiro)

• dune ocaml-merlin: communicate additional directives SOURCE_ROOT, UNIT_NAME (the actual name with wrapping) and INDEX with the paths to the index(es). (#10422, @voodoos)

• Add a new alias @ocaml-index that uses the ocaml-index binary to generate indexes that can be read by tools such as Merlin to provide project-wide references search. (#10422, @voodoos)

• Merlin: add optional (merlin_reader CMD) construct to (dialect) stanza to configure a Merlin reader (#8567, @andreypopp)

Changed

• Melange: treat private libraries with (package ..) as public libraries, fixing an issue where import paths were wrongly emitted. (#10415, @anmonteiro)

• Install .glob files for Coq theories too (#10602, @ejgallego)

Fixed

• Don't try to document nonexistent libraries in doc-new target (#10319, fixes #10056, @jonludlam)

• Make dune-site's load_all function look for META files so that it doesn't fail on empty directories in the plugin directory (#10458, fixes #10457, @shym)

• Fix incorrect warning for libraries defined inside nonexistant directories using (subdir ..) and used by executables using dune-build-info (#10525, @rgrinberg)

• Don't try to take build lock when running coq top --no-build (#10547, fixes #7671, @lzy0505)

• Make sure to truncate Dune's lock file after locking and unlocking so that users cannot observe incorrect PID's (#10575, @rgrinberg)

• MDX: link MDX binary with byte_complete. This fixes (libraries) with foreign archives on Linux. (#10586, fixes #10582, @anmonteiro)

• Virtual libraries: fix an issue where linking an executable involving several virtual libries would cause an error. (#10581, fixes #10460, @rgrinberg)

• merlin binary
  • Addition of a merlin-lib.commands library which disassociates the execution of commands from the new_protocol, from the binary, allowing it to be invoked from other projects (ocaml/merlin#1758)
  • merlin-lib.commands: Add a find_command_opt alternative to find_command that does not raise (ocaml/merlin#1778)

• merlin binary
  • destruct: Removal of residual patterns (ocaml/merlin#1737, fixes ocaml/merlin#1560)
  • Do not erase fields' names when destructing punned record fields (ocaml/merlin#1734, fixes ocaml/merlin#1661)
  • Ignore SIGPIPE in the Merlin server process (ocaml/merlin#1746)
  • Fix lexing of quoted strings in comments (ocaml/merlin#1754, fixes ocaml/merlin#1753)
  • Improve cursor position detection in longidents (ocaml/merlin#1756)

Fixed

• Fix interpretation of exists_if predicate in META files of installed libraries containing more than one element. (#10564, fixes #10563, @dbuenzli, @nojb)

• Fix TSAN warning in wait4 stubs (#10554, fixes #10553, @emillon)

• Changes necessary for opam repository
• Warn if GNU patch is not detected when a patch is applied [#5893 @kit-ty-kate]
• Use gpatch by default instead of patch on NetBSD and DragonFlyBSD [#5893 @kit-ty-kate]
• Use gpatch if it exists and is detected as GNU patch when patch is not GNU patch [#5893 @kit-ty-kate]
• Better recognize depexts on Gentoo, NetBSD, OpenBSD [#5065 @mndrix]
• Upgrade the vendored dune to 3.14.0 [#5869 @kit-ty-kate]
• Vendor mccs.1.1+17 [#5769 @kit-ty-kate]
• Require mccs >= 1.1+17: Fix debug logs showing up regardless of verbosity on macOS 12.7.1 / 13.6.3 / 14.2 and FreeBSD [#5769 @kit-ty-kate]
• API Changes:
• OpamSystem.patch now displays a warning when GNU patch is not detected and looks for both patch and gpatch as a backup option depending on the OS [#5893 @kit-ty-kate]

• merlin binary
  • Support for OCaml 5.2 (#1757)
  • destruct: Removal of residual patterns (#1737, fixes #1560)
  • Do not erase fields' names when destructing punned record fields (#1734, fixes #1661)
  • Ignore SIGPIPE in the Merlin server process (#1746)
  • Fix lexing of quoted strings in comments (#1754, fixes #1753)
  • Improve cursor position detection in longidents (#1756)
  • Addition of a merlin-lib.commands library that disassociates the execution of commands from the new_protocol, from the binary, allowing it to be invoked from other projects (#1758)
  • New occurrences backend: Don't index occurrences when merlin.hide attribute is present. (#1768)
  • Use the new uid_to_decl table in 5.2's CMT files to get documentation. (#1773)

(Changes that can break existing programs are marked with a "*")

Restored and New Backends:

• #12276, #12601: Native-code compilation for POWER (64 bits, little-endian) (Xavier Leroy, review by KC Sivaramakrishnan, Anil Madhavapeddy, and Stephen Dolan)

• #12667: Extend the latter to POWER 64 bits, big-endian, ELFv2 ABI (A. Wilcox, review by Xavier Leroy)

Runtime System:

• #12193: Reintroduce GC compaction for shared pools. Adds a parallel compactor for the shared pools (which contain major heap blocks sized less than 128 words). Explicit only for now, on calls to Gc.compact. (Sadiq Jaffer, Nick Barnes, review by Anil Madhavapeddy, Damien Doligez, David Allsopp, Miod Vallat, Artem Pianykh, Stephen Dolan, Mark Shinwell, and KC Sivaramakrishnan)

• #12114: Add ThreadSanitizer support (Fabrice Buoro and Olivier Nicole, based on an initial work by Anmol Sahoo, review by Damien Doligez, Sébastien Hinderer, Jacques-Henri Jourdan, Luc Maranget, Guillaume Munch-Maccagnoni, Gabriel Scherer)

• #12850: Update Gc.quick_stat data at the end of major cycles and compaction. This PR adds an additional caml_collect_gc_stats_sample_stw to the major heap cycling STW. This means that Gc.quick_stat now actually reflects the state of the heap after a major cycle or compaction. (Sadiq Jaffer, review by Miod Vallat and Gabriel Scherer)

• #12859: Ensure Gc.compact does a full major before the compactor runs (Sadiq Jaffer, review by Leo White, Mark Shinwell, Gabriel Scherer, Josh Berdine, David Allsopp, and KC Sivaramakrishnan)

• #10111: Increase the detail of location information for debugging events to allow the end-line number and character offset to be reported. (David Allsopp, review by Nick Barnes, Enguerrand Decorne and Stephen Dolan)

• #10403, #12202: Introduce caml_ext_table_add_noexc that does not raise Out_of_memory exceptions, and use it inside the blocking sections of caml_read_directory. Also, check for overflows in EXT table sizes. (Xavier Leroy, report by Arseniy Alekseyev, review by Gabriel Scherer)

• #11332, #12702: Make sure Bool_val(v) has type bool in C++ (Xavier Leroy, report by ygrek, review by Gabriel Scherer)

• #12772, #12787: Avoid using _Bool in public headers for the sake of C++ compatibility (Guillaume Munch-Maccagnoni, report by KC Sivaramakrishnan, review by Xavier Leroy and KC Sivaramakrishnan)

• #12223: Constify constructors and flags tables in C code. Now these tables will go in the read-only segment where they belong. (Antonin Décimo, review by Gabriel Scherer and Xavier Leroy)

• #12234: Make instrumented time calculation more thread-safe on macOS. (Anil Madhavapeddy, review by Daniel Bünzli and Xavier Leroy)

• #12235, #12468: Introduce and use the CAMLnoret macro as a lighter alternative to CAMLnoreturn_start / CAMLnoreturn_end. Implement it so as to conform with C11, C23, C++11, C++17. (Xavier Leroy and Dhruv Maroo, with help from Antonin Décimo, review by Gabriel Scherer and David Allsopp)

• #12275: caml/stack.h: More abstract macros to describe OCaml stacks and how to traverse them, supporting more stack layouts. (Xavier Leroy, review by KC Sivaramakrishnan and Fabrice Buoro)

• #12268: Deliver Out_of_memory exception if domain creation fails due to memory resource exhaustion. Previously, it was always a Failure. (Anil Madhavapeddy, review by David Allsopp)

• #12300, #12314: Discard out_channel buffered data on permanent I/O error (Xavier Leroy, report by Török Edwin, review by Anil Madhavapeddy and Nicolás Ojeda Bär)

• #11386: Simplifications and fixes to Multicore systhreads implementation. (Guillaume Munch-Maccagnoni, review by Anil Madhavapeddy and KC Sivaramakrishnan)

• #12875, #12879, #12882: Execute preemptive systhread switching as a delayed pending action. This ensures that one can reason within the FFI that no mutation happens on the same domain when allocating on the OCaml heap from C, consistently with OCaml 4. This also fixes further bugs with the Multicore systhreads implementation. (Guillaume Munch-Maccagnoni, bug reports and suggestion by Mark Shinwell, review by Nick Barnes and Stephen Dolan)

• #12408: Domain.spawn no longer leaks its functional argument for the whole duration of the children's domain lifetime. (Guillaume Munch-Maccagnoni, review by Gabriel Scherer)

• #12409: Fix unsafety and deadlocks should an asynchronous exception arise at specific locations during domain creation and shutdown. (Guillaume Munch-Maccagnoni, review by Gabriel Scherer)

• #11911, #12381: Restore statmemprof functionality in part, with some API changes in Gc.Memprof. (Nick Barnes, review by Jacques-Henri Jourdan and Guillaume Munch-Maccagnoni).

• #12430: Simplify dynamic bytecode loading in Meta.reify_bytecode (Stephen Dolan, review by Sébastien Hinderer, Vincent Laviron and Xavier Leroy)

• #12489: Fix an error-handling bug in caml_alloc_sprintf (Stephen Dolan, report by Chris Casinghino, review by Jeremy Yallop and Xavier Leroy)

• #11307: Finish adapting the implementation of asynchronous actions for Multicore: soundness, liveness, and performance issues. Do not crash if a signal handler is called from an unregistered C thread and other possible soundness issues. Prevent issues where joins on other domains could make the toplevel unresponsive to Ctrl-C. Avoid needless repeated polling in C code when callbacks cannot run immediately. (Guillaume Munch-Maccagnoni, review by Enguerrand Decorne, Xavier Leroy, and KC Sivaramakrishnan)

• #12634: Simplify TSan backtrace bookkeeping upon raise (Olivier Nicole and Fabrice Buoro, review by Gabriel Scherer)

• (Breaking Change) #12686: Some primitives had the wrong types to be callable from the bytecode interpreter. Either fix their types, mark them as CAMLexport instead of CAMLprim, or remove them entirely if no longer used. (Xavier Leroy, review by David Allsopp)

• #12700, continuing #11763 and trying to address #12660: Use the correct types for primitives when generating the table of primitives used by ocamlrun. (Xavier Leroy, motivation, review and improvements by Antonin Décimo)

• #12345, #12710: Fix issues with finaliser orphaning at domain termination (KC Sivaramakrishnan, report by Gabriel Scherer, review by Gabriel Scherer, Sadiq Jaffer and Fabrice Buoro)

• #12599: Refactor Dynlink startup to avoid parsing bytecode sections twice (Stephen Dolan, review by David Allsopp, Hugo Heuzard, Damien Doligez and Xavier Leroy)

• #12678, #12898: Free channel buffers on close rather than on finalisation (Damien Doligez, review by Jan Midtgaard and Gabriel Scherer, report by Jan Midtgaard)

• #12681: Fix TSan false positives due to volatile write handling (Olivier Nicole, Fabrice Buoro, and Anmol Sahoo, review by Luc Maranget, Gabriel Scherer, Hernan Ponce de Leon, and Xavier Leroy)

• #12743: Use pthread_sigmask instead of sigprocmask. Updates usage of sigprocmask to pthread_sigmask in otherlibs/unix. (Max Slater, review by Miod Vallat and Xavier Leroy)

• #12769: Unify MSVC and MinGW-w64 code paths, by always using WinAPI directly. (David Allsopp, Antonin Décimo, and Samuel Hym, review by Nicolas Ojeda Bar)

• #11911, #12382, #12383: Restore statmemprof functionality in part (backtrace buffers, per-thread and per-domain data structures, GC/allocation interface). (Nick Barnes, review by Gabriel Scherer, Fabrice Buoro, Sadiq Jaffer, Guillaume Munch-Maccagnoni, and Jacques-Henri Jourdan).

• #12735: Store both ends of the stack chain in continuations (Leo White, review by Miod Vallat and KC Sivaramakrishnan)

• #12746: Simplify and clean up TSan annotations (Olivier Nicole, review by Miod Vallat and Fabrice Buoro)

• #12809: Add ThreadSanitizer support to FreeBSD/AMD64 (Miod Vallat, review by Gabriel Scherer)

• #12810: Port ThreadSanitizer support to Linux and macOS on arm64 (Miod Vallat, review by Tim McGilchrist)

• #12811: Define and use the CAMLthread_local macro for TLS variables. (Antonin Décimo and Samuel Hym, review by Miod Vallat and Xavier Leroy)

• #12814: More detailed failure messages from input_value and Marshal.from_* (Xavier Leroy, review by Stephen Dolan and Anil Madhavapeddy)

• #12815: Correctly format multiline locations in exception backtraces in the compiler driver's style. (David Allsopp, review by Gabriel Scherer)

• #12773, #12830, #12834: Rewrite caml_c_thread_(un)register to fix various bugs. (Guillaume Munch-Maccagnoni, reported by Miod Vallat, suggested by Hari Hara Naveen S, reviewed by Fabrice Buoro, Gabriel Scherer, and Miod Vallat)

• #12876: Port ThreadSanitizer support to Linux on POWER (Miod Vallat, review by Tim McGilchrist)

• #12886: Reinitialise I/O mutexes after fork (Max Slater, review by Guillaume Munch-Maccagnoni and Xavier Leroy)

• #12907: Port ThreadSanitizer support to Linux on RiscV (Miod Vallat, review by Nicolás Ojeda Bär and Fabrice Buoro)

• #12915: Port ThreadSanitizer support to Linux on s390x (Miod Vallat, review by Tim McGilchrist)

• #12934: Fix data races between marking and sweeping functions (Olivier Nicole, suggested by Stephen Dolan, review by Gabriel Scherer, Miod Vallat, and Damien Doligez)

Language Features:

• #12295, #12568: Give while true a polymorphic type, similarly to assert false (Jeremy Yallop, review by Nicolás Ojeda Bär and Gabriel Scherer, suggestion by Rodolphe Lepigre and John Whitington)

• #12044: Add local module open syntax for types.

    module A = struct
      type t = int
      type r = unit
      type s = string
    end
  
    type example = A.(t * r * s)
  

  (Alistair O'Brien, review by Gabriel Scherer, Nicolás Ojeda Bär, and Florian Angeletti)

• #11252, RFC 27: Support raw identifier syntax \#foo (Stephen Dolan, review by David Allsopp, Gabriel Scherer, and Olivier Nicole)

• #12315: Use type annotations from arguments in let rec (Stephen Dolan, review by Gabriel Scherer)

• #12375: Allow use of [@untagged] for all immediate types like char, bool, and variant with only constant constructors. (Christophe Raffalli, review by Gabriel Scherer)

• (Breaking Change) #12502: The compiler now normalises the newline sequence \r\n to a single \n character during lexing to guarantee that the semantics of newlines in string literals are not modified by Windows tools transforming \n into \r\n in source files. Warning 29 [eol-in-string] is not emitted anymore, as the normalisation gives more robust semantics to newlines in string literals. (Gabriel Scherer and Damien Doligez, review by Daniel Bünzli, David Allsopp, Andreas Rossberg, Xavier Leroy, report by Andreas Rossberg)

Standard Library:

• #11563: Add the Dynarray module to the stdlib. Dynamic arrays are arrays whose length can be changed by adding or removing elements at the end, similar to 'vectors' in C++ or Rust. (Gabriel Scherer, Simon Cruanes, and Florian Angeletti, review by Daniel Bünzli, Guillaume Munch-Maccagnoni, Clément Allain, Damien Doligez, Wiktor Kuchta, and Pieter Goetschalckx)

• #12716: Add Format.pp_print_nothing function. (Léo Andrès, review by Gabriel Scherer and Nicolás Ojeda Bär)

• (Breaking Change) #6732, #12423: Make Buffer.add_substitute surjective and fix its documentation. (Damien Doligez, review by Antonin Décimo)

• (Breaking Change) #10775, #12499: Half-precision, floating-point elements in Bigarray. (Anton Yabchinskiy, review by Xavier Leroy and Nicolás Ojeda Bär)

• #11517, #12477: Expose pp_infinity in interface of the format module and check that margin is less than pp_infinity when setting or checking geometry. (Janith Petangoda, reported by Simmo Saan, reviewed by Florian Angeletti, Simmo Saan, Josh Berdine, and Gabriel Scherer)

• #12217: Add Array.shuffle. (Daniel Bünzli, review by Nicolás Ojeda Bär, David Allsopp, and Alain Frisch)

• #12212: Add cache-aligned constructor for atomics. The patch ensures that all allocations (of the right size) in the shared heap are aligned. (Bartosz Modelski with Gabriel Scherer, Guillaume Munch-Maccagnoni, Xavier Leroy, review by Alain Frisch, Anil Madhavapeddy, Gabriel Scherer, Guillaume Munch-Maccagnoni, KC Sivaramakrishnan, Stefan Muenzel, Xavier Leroy)

• #12307: Add BLAKE2b hashing and an MD5 submodule to the Digest module. (Xavier Leroy, review by Olivier Nicole, Gabriel Scherer, Wiktor Kuchta, Daniel Bünzli, David Allsopp)

• #12365: Add In_channel.input_bigarray, In_channel.really_input_bigarray, Out_channel.output_bigarray, Unix.read_bigarray, Unix.write_bigarray, Unix.single_write_bigarray. (Nicolás Ojeda Bär, review by Jeremy Yallop, Xavier Leroy, Gabriel Scherer, David Allsopp)

• #12455: Add Array.init_matrix, Float.Array.make_matrix, Float.Array.init_matrix. (Glen Mével, review by Xavier Leroy, Gabriel Scherer, Jeremy Yallop, Nicolas Ojeda Bar)

• (Breaking Change) #12455: Array.make_matrix dimx dimy f now raises Invalid_argument when dimx = 0 && dimy < 0. This was already specified but not enforced. (Glen Mével, report by Jeremy Yallop, review by Nicolas Ojeda Bar)

• #12459: Add Random.int_in_range, Random.int32_in_range, Random.int64_in_range, Random.nativeint_in_range, and their counterpart in Random.State. (Glen Mével and Xavier Leroy, review by Gabriel Scherer, Xavier Leroy, Florian Angeletti)

• #12459: Random: Restore compatibility between 32-bit integers (JavaScript) and 63-bit integers (64-bit OCaml). For Random.full_int this was guaranteed in 4.14 but wrongly removed in 5.0. (Xavier Leroy, review by Glen Mével)

• #12511: Minor performance improvements and cleanups in the implementation of modules Int32, Int64, and Nativeint (Xavier Leroy, review by Gabriel Scherer and Daniel Bünzli)

• #12558: Adapt GC alarms for Multicore and fix their documentation. (Guillaume Munch-Maccagnoni, review by KC Sivaramakrishnan and Gabriel Scherer)

• #12625: Remove the Closure module from Obj (Vincent Laviron, review by Xavier Leroy)

• #12758, #12998: Remove the Marshal.Compression flag to the Marshal.to_* functions. The compilers are still able to use ZSTD compression for compilation artefacts. This is a forward port and clean-up of the emergency fix that was introduced in OCaml 5.1.1 by #12734. (Xavier Leroy, review by Damien Doligez)

• #12784: Fix computation of minor-heap allocation in Gc.counters() and Gc.allocated_bytes(). (Nick Barnes, review by Gabriel Scherer)

• #12770: Add Fun.compose. (Justin Frank, review by Nicolás Ojeda Bär, Daniel Bünzli, and Jeremy Yallop)

• #12845: Add {In,Out}_channel.is_binary_mode as the dual of set_binary_mode. This function was previously only available in the internal C API. (David Allsopp, review by Nicolás Ojeda Bär and Xavier Leroy)

Type System:

• #12313, #11799: Do not rebuild as-pattern types when a ground type annotation is given. This allows to work around problems with GADTs in as-patterns. (Jacques Garrigue, report by Leo White, review by Gabriel Scherer)

Code Generation and Optimisations:

• #11239: On x86-64 and RISC-V, reduce alignment of OCaml stacks from 16 to 8. This reduces stack usage. It's only C stacks that require 16-alignment. (Xavier Leroy, review by Gabriel Scherer and Stephen Dolan)

• #12311: On POWER, 32-bit FP numbers stored in memory (e.g., in Bigarrays) were not correctly rounded sometimes. (Xavier Leroy, review by Anil Madhavapeddy and Tim McGilchrist)

• #12551, #12608, #12782, #12596: Overhaul of recursive value compilation. Non-function recursive bindings are now forbidden from Lambda onwards, and they're compiled using a new Value_rec_compiler module. (Vincent Laviron and Lunia Ayanides, review by Gabriel Scherer, Stefan Muenzel and Nathanaëlle Courant)

• #1809, #12181: Rewrite compare x y op 0 to x op y when values are integers (Xavier Clerc, Stefan Muenzel, review by Gabriel Scherer and Vincent Laviron)

• #12825: Disable common subexpression elimination for atomic loads... again. (Gabriel Scherer, review by KC Sivaramakrishnan, Xavier Leroy and Vincent Laviron, report by Vesa Karvonen)

Other Libraries:

• #12213: Dynlink library, improve legibility of error messages (Samuel Hym, review by Gabriel Scherer and Nicolás Ojeda Bär)

• (Breaking Change) #12686: Runtime_events library, C API: define caml_runtime_events_{start,pause,resume} as returning void instead of value. (Xavier Leroy, review by David Allsopp)

Compiler User-Interface and Warnings:

• #11989, #12246, RFC 31: New flag, -H, to allow for transitive dependencies without including them in the initial environment. (Chris Casinghino, François Bobot, and Gabriel Scherer, review by Leo White and Stefan Muenzel, RFC by François Bobot)

• (Breaking Change) #10613, #12405: Simplify the values used for the system variable (system: in ocamlopt -config or the Config.system constant). In particular, s390x and ppc64 now report "linux" instead of "elf"; all variants of 32-bit ARM on Linux now report "linux"; OpenBSD now reports "openbsd" instead of "bsd" for 32-bit ARM; FreeBSD, NetBSD, and OpenBSD now report the same value for both x86_64 and x86_32; x86_32 systems matching BSD but not FreeBSD, NetBSD*, or OpenBSD* are no longer identified (as on x86_64); x86_32 Linux now reports "linux" instead of "linux_elf". (David Allsopp, request by Kate Deplaix, review by Sébastien Hinderer and Xavier Leroy)

• #12247: Configure: --disable-ocamldebug can now be used instead of --disable-debugger (which remains available for compatibility) (Gabriel Scherer, review by Damien Doligez and Sébastien Hinderer)

• #12199: Improve the error message for non-overriding inherit! (Florian Angeletti, review by Jules Aguillon)

• #12210: Uniform style for inline code in compiler messages (Florian Angeletti, review by Gabriel Scherer)

• (Breaking Change) #12278, #:12325: Remove the OCAML_FLEXLINK environment variable from the compiler drivers. This environment variable was previously used as part of the FlexDLL bootstrap procedure and existed solely for that purpose. Its removal greatly simplifies both the build system and testsuite machinery. (David Allsopp, review by Sébastien Hinderer)

• #12347: Error messages: always report missing polyvariant tags (Florian Angeletti, report by Tianbo Hao, review by Gabriel Scherer)

• #12224: Specialised error message when trying to apply non-functor module (e.g., module M = Int(Int)) (Florian Angeletti, review by Gabriel Scherer)

• #12451: Warning 53 (misplaced attributes) now works for all attributes. (Chris Casinghino, review by Florian Angeletti)

• #12622: Give hints about existential types appearing in error messages (Leo White, review by Gabriel Scherer and Florian Angeletti)

• #12671: When a class type parameter or class parameter does not match, identify which parameter in the error message, instead of saying "A type parameter" or "A parameter." (Stefan Muenzel, review by Gabriel Scherer)

• #12679: Add more detail to the error message and manual in case of invalid module type substitutions. (Stefan Muenzel, review by Gabriel Scherer and Florian Angeletti)

• #12750: Display the command executed to extract primitives in ocamlc -verbose (David Allsopp, review by Nicolás Ojeda Bär)

• #12777: Add details about the actual and expected method types to the method mismatch error messages (Javier Chávarri, review by Gabriel Scherer and Florian Angeletti)

• (Breaking Change) #12942: Fix line ordering in some module inclusion error messages (Nick Roberts, review by Florian Angeletti, report by Carl Eastlund)

Manual and Documentation:

• #12338: Clarification of the documentation of process related function in the Unix module regarding the first element of arguments and shell's PID (Christophe Raffalli, review by Florian Angeletti)

• #12473: Document in runtime/memory.c our current understanding of accesses to the OCaml heap from the C runtime code -- the problem of hybrid programs mixing two memory models (Gabriel Scherer and Guillaume Munch-Maccagnoni, review by Olivier Nicole and Xavier Leroy)

• #12456: Document the incompatibility between effects, on one hand, and caml_callback and asynchronous callbacks (signal handlers, finalisers, memprof callbacks...), on the other (Guillaume Munch-Maccagnoni, review by KC Sivaramakrishnan)

• #12694: Document in runtime/tsan.c the TSan instrumentation choices and the consequences with regard to the memory model (Olivier Nicole, review by Miod Vallat, Gabriel Scherer, Guillaume Munch-Maccagnoni and Fabrice Buoro)

• #12802: Add manual chapter about ThreadSanitizer support (Olivier Nicole, review by Miod Vallat, Sebastien Hinderer, Fabrice Buoro, Gabriel Scherer and KC Sivaramakrishnan)

• #12819: Clarify which runtime interactions are allowed in custom ops (Basile Clément, review by Guillaume Munch-Maccagnoni and Xavier Leroy)

• #12840: Manual: update runtime tracing chapter for custom events (e.g., #12335) (Lucas Pluvinage, Sadiq Jaffer and Olivier Nicole, review by Gabriel Scherer, David Allsopp, Tim McGilchrist, and Thomas Leonard)

• #13066: Update OCAMLRUNPARAM documentation for the stack size parameter l (Florian Angeletti, review by Nicolás Ojeda Bär, Tim McGilchrist, and Miod Vallat)

• #13078: Update Format tutorial on structural boxes to mention alignment questions (Edwin Török, review by Florian Angeletti)

• #13092: Document the existence of the [@@poll error] built-in attribute (Florian Angeletti, review by Gabriel Scherer)

Tools:

• #12340: testsuite: collect known issues with current -short-paths implementation for existential types (Florian Angeletti, Samuel Hym, review by Florian Angeletti and Thomas Refis)

• #12147: ocamllex: allow carriage returns at the end-of-line directives (SeungCheol Jung, review by Nicolás Ojeda Bär)

• #12260: Fix invalid_argument on some external or module aliases in ocamlnat (Fabian Hemmer, review by Vincent Laviron)

• #12185: New script language for ocamltest (Damien Doligez with Florian Angeletti, Sébastien Hinderer, Gabriel Scherer, review by Sébastien Hinderer and Gabriel Scherer)

• #12371: ocamltest: fix recursive expansion of variables (Antonin Décimo, Damien Doligez, review by Sébastien Hinderer, Damien Doligez, Gabriel Scherer, and Xavier Leroy)

• (Breaking Change) #12497, #12613: Make ocamlc/ocamlopt fail with an error when no input files are specified to build an executable (Antonin Décimo, review by Sébastien Hinderer)

• #12576: ocamldep : various refactors (Antonin Décimo, review by Florian Angeletti, Gabriel Scherer, and Léo Andrès)

• #12615: ocamldoc: get rid of the odoc_literate and odoc_todo generators (Sébaistien Hinderer, review by Gabriel Scherer and Florian Angeletti)

• #12624: Use $XDG_CONFIG_DIRS in addition to $XDG_CONFIG_HOME when searching for init.ml, and use this to extend init.ml support to the toplevel when running on Windows. (David Allsopp, report by Jonah Beckford, review by Nicolás Ojeda Bär and Antonin Décimo)

• #12688: Setting the env variable NO_COLOR with an empty value no longer has effects. Previously, setting NO_COLOR with any value, including the empty value, would disable colours (unless OCAML_COLOR is also set). After this change, the user must set NO_COLOR with an non-empty value to disable colours. This reflects a specification clarification/change from the upstream website at https://no-color.org. (Favonia, review by Gabriel Scherer)

• #12744: ocamltest: run tests in recursive subdirs more eagerly (Nick Roberts, review by Nicolás Ojeda Bär)

• #12901, 12908: ocamllex: add overflow checks to prevent generating incorrect lexers; use unsigned numbers in the table encoding when possible (Vincent Laviron, report by Edwin Török, review by Xavier Leroy)

Internal/compiler-libs Changes:

• #12508 : Add compiler-side support for project-wide occurrences in Merlin by generating index tables of all identifier occurrences. This extra data in .cmt files is only added when the new flag -bin-annot-occurrences is passed. (Ulysse Gérard, Nathanaëlle Courant, suggestions by Gabriel Scherer and Thomas Refis, review by Florian Angeletti, Gabriel Scherer, and Thomas Refis)

• #12236, #12386, #12391, #12496, #12673: Use syntax as sole determiner of arity. This changes function arity to be based solely on the source program's parsetree. Previously, the heuristic for arity had more subtle heuristics that involved type information about patterns. Function arity is important because it determines when a pattern match's effects run and is an input into the fast path for function application.

  This change affects tooling; it changes the function constructs in parsetree and typedtree.

  See https://github.com/ocaml/RFCs/pull/32 for the original RFC.

  (Nick Roberts; review by Richard Eisenberg, Leo White, and Gabriel Scherer; RFC by Stephen Dolan)

• #12639: Parsing: attach a location to the RHS of Ptyp_alias and improve the 'alias type mismatch' error message. (Jules Aguillon, review by Florian Angeletti)

• #12447: Remove 32-bit targets from X86_proc.system (Masanori Ogino, review by David Allsopp)

• #12216, #12248: Prevent reordering of atomic loads during instruction scheduling. This is for reference, as instruction scheduling is currently unused in OCaml 5. (Xavier Leroy, report by Luc Maranget and KC Sivaramakrishnan, review by Nicolás Ojeda Bär)

• #12025: Split Typecore.unify_pat_types into two in order to avoid unnecessary references to the environment in type_pat (Jacques Garrigue and Takafumi Saikawa, review by Gabriel Scherer)

• #12031: Use dedicated types to represent names of compilation units and predefined exceptions in CMO files. (Sébastien Hinderer, review by Florian Angeletti, Thomas Refis, Gabriel Scherer, Vincent Laviron, Pierre Chambart, Luke Maurer, Hugo Heuzard, Xavier Leroy, and Damien Doligez)

• #12109: Pack parameters to unification in unification_environment (Takafumi Saikawa and Jacques Garrigue, review by Richard Eisenberg)

• #12331, #12361: Pack the unification data for pattern checking in Typecore (Takafumi Saikawa and Jacques Garrigue, review by Gabriel Scherer, Thomas Refis, and Florian Angeletti)

• #12229: Remove global mutable state for typechecking patterns in Typecore in favor of local mutable state. (Nick Roberts, review by Takafumi Saikawa)

• #12542: Minor bugfix to #12236: restore dropped call to instance (Nick Roberts, review by Jacques Garrigue)

• #12242: Move the computation of stack frame parameters to a separate Stackframe module, and save the parameters in the results of the Linearize pass. (Xavier Leroy, review by KC Sivaramakrishnan and Mark Shinwell)

• #12442: Document jump summaries in the pattern-matching compiler (Gabriel Scherer and Thomas Refis, review by Florian Angeletti and Vincent Laviron)

• #12446, #12792: Remove the hooks machinery around channel locking in runtime/io.c (Gabriel Scherer, review by Xavier Leroy)

• #12389, #12544, #12984, #12987: Centralise the handling of metadata for compilation units and artifacts in preparation to improve Unicode support for OCaml source files. (Florian Angeletti, review by Vincent Laviron and Gabriel Scherer)

• #12532, #12553: Improve readability of the pattern-matching debug output (Gabriel Scherer, review by Thomas Refis)

• #12537: Use C11/C++11 standard static assertion (Antonin Décimo, review by Sebastien Hinderer, Xavier Leroy, and KC Sivaramakrishnan)

• #12169: Runtime: document and enforce naming conventions around STW sections (Gabriel Scherer, review by Enguerrand Decorne, Miod Vallat, B. Szilvasy and Nick Barnes, report by KC Sivaramakrishnan)

• #12669 : Clean up some global state handling in schedgen (Stefan Muenzel, review by Miod Vallat and Gabriel Scherer)

• #12640: Make the module separator used in symbol names configurable (Miod Vallat, review by Hugo Heuzard and Xavier Leroy)

• #12691 : Clean up Ctype.expand_abbrev_gen and rename Env.add_local_type to add_local_constraint (Takafumi Saikawa and Jacques Garrigue, review by Florian Angeletti)

• #12786 : Clean up the algorithm of Ctype.limited_generalize (Takafumi Saikawa and Jacques Garrigue, review by Gabriel Scherer)

• #10691: Ast_mapper, Ast_iterator: add functions directive_argument, toplevel_directive, and toplevel_phrase (Guillaume Petiot, review by Gabriel Scherer and Kate Deplaix)

• #12764: Move all installable headers in caml/ subdirectories. (Antonin Décimo, review by Gabriel Scherer and David Allsopp)

• #12914: Slightly change the s390x assembly dialect in order to build with Clang's integrated assembler (Miod Vallat, review by Gabriel Scherer)

• #13001: Do not read_back entire shapes to get aliases' UIDs when building the usages index (Ulysse Gérard, review by Gabriel Scherer and Nathanaëlle Courant)

Build System:

• #12198, #12321, #12586, #12616, #12706, #13048: Continue the merge of the sub-Makefiles into the root Makefile started with #11243, #11248, #11268, #11420 and #11675. (Sébastien Hinderer, review by David Allsopp and Florian Angeletti)

• #12569, #12570: Remove otherlibraries as a prerequisite for runtop; use runtop-with-otherlibs to use a library from otherlibs/ (Gabriel Scherer, review by Sébastien Hinderer, suggestion by David Allsopp)

• #12652: Make magic numbers easier to bump and duplicate (Sébastien Hinderer, review by Antonin Décimo, David Allsopp and Florian Angeletti)

• (Breaking Change) #12751: --with-target-bindir configure option implemented. This option refers to the location of the runtime binaries on the target system for a cross-compiler and is embedded in executables produced by ocamlc. It does not affect the bytecode executables installed as part of the build. The old mechanism make TARGET_BINDIR=.. no longer works. (David Allsopp, review by Damien Doligez, Xavier Leroy, and Olivier Nicole)

• #12768, #13030: Detect MinGW-w64 coupling with GCC or LLVM, detect clang-cl, and fix C compiler feature detection on macOS. (Antonin Décimo, review by Miod Vallat and Sébastien Hinderer)

Bug Fixes:

• #10652, #12720: Fix evaluation order in presence of optional arguments (Jacques Garrigue, report by Leo White, review by Vincent Laviron)

• #12595, #12597: Fix a race in caml_clear_gc_stats_sample (Gabriel Scherer, review by B. Szilvasy, report by B. Szilvasy)

• #12580: Fix location of alias pattern variables (Chris Casinghino, review Gabriel Scherer, report by Milo Davis)

• #12583: Add a closing event for when EV_MAJOR_EPHE_MARK is complete (Sudha Parimala, review by Gabriel Scherer)

• #12566: caml_output_value_to_malloc wrongly uses caml_stat_alloc instead of malloc since 4.06, breaking (in pooled mode) user code that uses free on the result. Symmetrically, caml_input_value_from_malloc should use free. (Gabriel Scherer, review by Xavier Leroy and Enguerrand Decorne, report by Ido Yariv)

• #12490: Unix: protect the popen_processes hashtable with a mutex (Gabriel Scherer, report by Olivier Nicole, review by Xavier Leroy)

• #11931: Fix tricky typing bug with type substitutions (Stephen Dolan, review by Leo White and Jacques Garrigue)

• #12037, #12171: Fix get_extern_state potential NULL dereference (Alexander Skvortsov, report by Török Edwin, design by Gabriel Scherer, Xavier Leroy)

• #12635: Fix get_intern_state potential NULL dereference (Antonin Décimo, review by KC Sivaramakrishnan)

• #12032, #12059: Bug fixes related to compilation of recursive definitions (Vincent Laviron, report by Victoire Noizet, review by Gabriel Scherer)

• (Breaking Change) #12145: Loopy constraints cause ocamlc to loop. Fixed by completely removing the call to update_type in Typedecl.transl_type_decl, as the expansion is already checked by check_regularity. As a result, recursion is more polymorphic, which may cause some (essentially wrong) type declarations to have unbound type variables and some constraints unrelated to the concrete type to be ignored (see tests/typing-misc/constraints.ml). (Jacques Garrigue, report by Richard Eisenberg, review by Leo White)

• #12207, #12222: Make closure computation linear in the number of recursive functions instead of quadratic (Vincent Laviron, report by François Pottier, review by Nathanaëlle Courant and Gabriel Scherer)

• #11040, #12591: Fix a data race in major_gc.c (Gabriel Scherer, review by Guillaume Munch-Maccagnoni and KC Sivaramakrishnan, report by Sadiq Jaffer)

• #12238, #12403, #12698: Read input files in one go to avoid source reprinting issues (Gabriel Scherer, report by Mike Spivey and Vincent Laviron, review by Nicolás Ojeda Bär, Xavier Leroy and Jeremy Yallop)

• #12334, #12368: Bad error message with mutually recursive abbreviations (Jacques Garrigue, report by Richard Eisenberg, review by Gabriel Scherer and Richard Eisenberg)

• #12401: seek_in and seek_out sometimes returned normally when given negative offsets, instead of failing. Now both functions should consistently raise Sys_error in this case. (Nicolás Ojeda Bär, review by Gabriel Scherer)

• #12267: Fix stack alignment computation (Miod Vallat, report by Jan Midtgaard, review by Gabriel Scherer)

• #12395, #12404: Fix thread-unsafety in the fallback implementation of Unix.create_process (the one used when posix_spawnp is unavailable) (Xavier Leroy, report by Chris Vine, review by Nicolás Ojeda Bär)

• #12949: Open shadowing mistriggers (Gabriel Scherer, review by Florian Angeletti, report by Andreas Rossberg)

• #12526: Honor ocaml.inline always attribute on functions with optional arguments and default values in the Closure backend (Alain Frisch, review by Vincent Laviron)

• #12677, #12889: Make Domain.DLS thread-safe (Gabriel Scherer, review by Olivier Nicole and Damien Doligez, report by Vesa Karvonen)

• #12561: Fix crash when combining TSan and frame-pointers (Fabrice Buoro and Olivier Nicole, report by Jan Midtgaard, review by Miod Vallat and Gabriel Scherer)

• #12482: Rework bounds checking code in the POWER backend (Miod Vallat and Xavier Leroy, report by Jan Midtgaard, review by KC Sivaramakrishnan)

• #12528, #12703: Avoid pointer arithmetic overflow in Tag_val macro (very likely harmless, but can trigger alarms) (Xavier Leroy, report by Sam Goldman, review by Guillaume Munch-Maccagnoni)

• #12593: TSan should handle Effect.Unhandled correctly (Fabrice Buoro and Olivier Nicole, report by Jan Midtgaard and Miod Vallat, review by Gabriel Scherer)

• #12684: Fix locations filename in AST produced by the -pp option (Gabriel Scherer, review by Florian Angeletti)

• #12714: Check whether macros are defined before using them to ensure that the headers can always be used in code which turns on -Wundef (or equivalent). (Antonin Décimo, review by Miod Vallat, Gabriel Scherer, Xavier Leroy, and David Allsopp)

• #12726: Fix segmentation fault under Windows when executing a bytecode file if the runtime (ocamlrun.exe) cannot be found. (Vadim Zborovskii, Nicolás Ojeda Bär, report by Vadim Zborovskii, review by David Allsopp)

• #12727, #12730: Fix bug with value let-rec and labelled applications (Vincent Laviron, review by Gabriel Scherer)

• (Breaking Change) #12751: Always keep within the 128 character limit for shebang lines. Previous fix in #8622 handled building the compiler with a long prefix. This patch extends this to the bytecode executables emitted by that compiler. (David Allsopp, review by Damien Doligez, Xavier Leroy, and Olivier Nicole)

• #12755: Fix data race on global pools arrays of pool_freelist (Fabrice Buoro and Olivier Nicole, review by Gabriel Scherer)

• #12796, #12801: Fix memory corruption in caml_unix_alloc_sockaddr (Thomas Leonard, review by Nicolás Ojeda Bär)

• #12737: Fix data races in minor_gc.c and caml_natdynlink_open (Olivier Nicole, review by Stefan Muenzel, Miod Vallat, Guillaume Munch-Maccagnoni, Gabriel Scherer, and Xavier Leroy)

• #12831: Fix call to caml_call_realloc_stack for s390x in PIC mode (Vincent Laviron, report by Jerry James, review by Miod Vallat)

• (Breaking Change) #12837: Show non-generalisable type parameters in type definitions Changes type of type parameters in outcometree.mli. (Jacques Garrigue, review by Richard Eisenberg)

• #12897: Fix locking bugs in Runtime_events (Gabriel Scherer and Thomas Leonard, review by Olivier Nicole, Vincent Laviron, and Damien Doligez, report by Thomas Leonard)

• #12851: Fix race between runtime events teardown and event emission (Olivier Nicole, review by Miod Vallat and Gabriel Scherer)

• #12860: Fix an assertion that wasn't taking into account the possibility of an ephemeron pointing at static data (Mark Shinwell, review by Gabriel Scherer and KC Sivaramakrishnan)

• #12861: Fix a possible crash in the threads library (Mark Shinwell, review by Gabriel Scherer and KC Sivaramakrishnan)

• #11040, #12894: Silence false data race observed between caml_shared_try_alloc and oldify. Introduces macros to call TSan annotations which help annotate a "happens before" relationship. (Hari Hara Naveen S and Olivier Nicole, review by Gabriel Scherer and Miod Vallat)

• #12958: Fix tail-modulo-cons compilation of try-with, &&, and || expressions. (Gabriel Scherer and Nicolás Ojeda Bär, report by Sylvain Boilard, review by Gabriel Scherer)

• #12919: Fix register corruption in caml_callback2_asm on s390x. (Miod Vallat, review by Gabriel Scherer)

• #12924, #12930: Rework package constraint checking to improve interaction with immediacy (Chris Casinghino and Florian Angeletti, review by Florian Angeletti and Richard Eisenberg)

• #12969: Fix a data race in caml_darken_cont (Fabrice Buoro and Olivier Nicole, review by Gabriel Scherer and Miod Vallat)

• #12971, #12974: Fix an uncaught Ctype.Escape exception on some invalid programs forming recursive types. (Gabriel Scherer, review by Florian Angeletti, report by Neven Villani)

• #13019: Remove linking instructions for the Unix library from threads.cma. (This was done for threads.cmxa in OCaml 3.11.) Eliminates warnings from new LLD when using threads.cma of duplicated libraries. (David Allsopp, review by Nicolás Ojeda Bär)

• #13058: Add TSan instrumentation to caml_call_gc(), since it may raise exceptions. (Fabrice Buoro, Olivier Nicole, Gabriel Scherer, and Miod Vallat)

• #13079: Save and restore frame pointer across Iextcall on ARM64 (Tim McGilchrist, review by KC Sivaramakrishnan and Miod Vallat)

• #13094: Fix undefined behavior of left-shifting a negative number (Antonin Décimo, review by Miod Vallat and Nicolás Ojeda Bär)

• #13130: Minor fixes to Pprintast for raw identifiers and local module open syntax for types (Chet Murthy, review by Gabriel Scherer)

• Add support for OCaml 5.2

• Insert errors from caught located exceptions in place of the code that should have been generated by context-free rules. (#472, @NathanReb)

Added

• OCaml 5.2.0 compatibility (@Octachron, #1094, #1112)

Fixed

• Fix issues #1066 and #1095 with extended opens (@jonludlam, #1082, #1100)

Changed

• Compatible with OCaml 5.2.0 (#2510, @gpetiot, @Julow)

Fixed

• If no directory targets are defined, then do not evaluate enabled_if (#10442, @rgrinberg)

• Fix a bug where Coq projects were being rebuilt from scratch each time the dependency graph changed. (#10446, fixes #10149, @alizter)

Changed

• Revert #446: "Allow execution of included OCaml code blocks" (#451, @gpetiot). Included OCaml code blocks preserve their pre-2.4.0 behavior.

Added

• Add link flags to to ocamlmklib for ctypes stubs (#8784, @frejsoya)

• Remove some unnecessary limitations in the expansions of percent forms in install stanza. For example, the %{env:..} form can be used to select files to be installed. (#10160, @rgrinberg)

• Allow artifact expansion percent forms (%{cma:..}, %{cmo:..}, etc.) in more contexts. Previously, they would be randomly forbidden in some fields. (#10169, @rgrinberg)

• Allow %{inline_tests} in more contexts (#10191, @rgrinberg)

• Remove limitations on percent forms in the (enabled_if ..) field of libraries (#10250, @rgrinberg)

• Support dialects in dune describe pp (#10283, @emillon)

• Allow defining executables or melange emit stanzas with the same name in the same folder under different contexts. (#10220, @rgrinberg, @jchavarri)

Fixed

• coq: Delay Coq rule setup checks so OCaml-only packages can build in hybrid Coq/OCaml projects when coqc is not present. Thanks to @vzaliva for the test case and report (#9845, fixes #9818, @rgrinberg, @ejgallego)

• Fix conditional source selection with select on bigarray in OCaml 5 (#10011, @moyodiallo)

• melange: fix inconsistency in virtual library implementation. Concrete modules within a virtual library can now refer to its virtual modules too (#10051, fixes #7104, @anmonteiro)

• melange: fix a bug that would cause stale import paths to be emitted when moving source files within (include_subdirs ..) (#10286, fixes #9190, @anmonteiro)

• Dune file formatting: output utf8 if input is correctly encoded (#10113, fixes #9728, @moyodiallo)

• Fix expanding dependencies and locks specified in the cram stanza. Previously, they would be installed in the context of the cram test, rather than the cram stanza itself (#10165, @rgrinberg)

• Fix bug with dune exec --watch where the working directory would always be set to the project root rather than the directory where the command was run (#10262, @gridbugs)

• Regression fix: sign executables that are promoted into the source tree (#10263, fixes #9272, @emillon)

• Fix crash when decoding dune-package for libraries with (include_subdirs qualified) (#10269, fixes #10264, @emillon)

Changed

• Remove the --react-to-insignificant-changes option. (#10083, @rgrinberg)

Added

• Handle the error-blocks syntax (#439, @jonludlam, @gpetiot)
• Allow execution of included OCaml code blocks. Add skip to include blocks to revert to the old behavior (#446, @panglesd, @gpetiot) Warning: this is a breaking change that is reverted in the next release.
• Make MDX compatible with OCaml 5.2 (#448, @gpetiot)

Fixed

• Reduce false-positives while detecting warnings (#440, @Julow)

Fixed

• When a directory is changed to a file, correctly remove it in subsequent dune build runs. (#9327, fix #6575, @emillon)

• Fix a problem with the doc-new target where transitive dependencies were missed during compile. This leads to missing expansions in the output docs. (#9955, @jonludlam)

• coq: fix performance regression in coqdep unescaping (#10115, fixes #10088, @ejgallego, thanks to Dan Christensen for the report)

• coq: memoize coqdep parsing, this will reduce build times for Coq users, in particular for those with many .v files (#10116, @ejgallego, see also #10088)

• on Windows, use an unicode-aware version of CreateProcess to avoid crashes when paths contains non-ascii characters. (#10212, fixes #10180, @emillon)

• fix compilation on non-glibc systems due to signal.h not being pulled in spawn stubs. (#10256, @emillon)

• Add support for OCaml 5.2 (#470, fixes #466, @leostera, @ManasJayanth, @huwaireb)

• merlin binary
  • Add a "heap_mbytes" field to Merlin server responses to report heap usage (#1717)
  • Add cache stats to telemetry (#1711)
  • Add new SyntaxDocument command to find information about the node under the cursor (#1706)
  • Fix FLG -pp ppx.exe -as-pp/-dump-ast use of invalid shell redirection when direct process launch on Windows. (#1723, fixes #1722)
  • Add a query_num field to the ocamlmerlin responses to detect server crashes (#1716)
  • Jump to cases within a match statement (#1726)
  • Jump to module-type (#1728, partially fixes #1656)
  • Exposes stable functions for configuration handling and pattern variable destruction. (#1730)
• editor modes
  • vim: load merlin under the ocamlinterface and ocamllex filetypes (#1340)
  • Fix merlinpp not using binary file open (#1725, fixes #1724)

Added

• Introduce a (dynamic_include ..) stanza. This is like (include foo) but allows foo to be the target of a rule. Currently, there are some limitations on the stanzas that can be generated. For example, public executables, libraries are currently forbidden. (#9913, @rgrinberg)

• Introduce $ dune promotion list to print the list of available promotions. (#9705, @moyodiallo)

• If Sherlodoc is installed, add a search bar in generated HTML docs (#9772, @EmileTrotignon)

• Add only_sources field to copy_files stanza (#9827, fixes #9709, @jchavarri)

• The (foreign_library) stanza now supports the (enabled_if) field. (#9914, @nojb)

Fixed

• Fix $ dune install -p incorrectly recognizing packages that are supposed to be filtered (#9879, fixes #4814, @rgrinberg)

• subst: correctly handle opam files in opam/ subdirectory (#9895, fixes #9862, @emillon)

• Odoc private rules are not set up if a library is not available due to enabled_if (#9897, @rgrinberg and @jchavarri)

Changed

• When dune language 3.14 is enabled, resolve the binary in (run %{bin:..} ..) from where the binary is built. (#9708, @rgrinberg)

• boot: remove single-command bootstrap. This was an alternative bootstrap strategy that was used in certain conditions. Removal makes the bootstrap a bit slower on Linux when only a single core is available, but bootstrap is now reproducible in all cases. (#9735, fixes #9507, @emillon)

• Add an optional embed_errors argument to Context_free.map_top_down that controls how to deal with exceptions thrown by context-free rules. (#468, @NathanReb)

• Fix Longident.parse so it properly handles unparenthesized dotted operators such as +. or *.. (#111, @rgrinberg, @NathanReb)

• raising an exception does no longer cancel the whole context free phase(#453, @burnleydev1)

• Sort embedded errors that are appended to the AST by location so the compiler reports the one closer to the beginning of the file first. (#463, @NathanReb)

• Update Attribute.get to ignore loc_ghost. (#460, @ceastlund)

• Add API to manipulate attributes that are used as flags (#408, @dianaoigo)

• Update changelog to use ISO 8061 date format: YYYY-MM-DD. (#445, @ceastlund)

• Replace Caml with Stdlib. (#427, @ceastlund)

• When a transformation raises, the last valid AST is used as input to the upcoming transformations. All such errors are collected and appended as extension nodes to the final AST (#447, @burnleydev1)

• Fix a small mistake in the man pages: Embededding errors is done by default with -as-pp, not with -dump-ast (#464, @pitag-ha)

• Set appropriate binary mode when writing to stdout especially for Windows compatibility. (#466, @jonahbeckford)

• Fix performance regression for incremental builds (#9769, fixes #9738, @rgrinberg)

• Fix dune ocaml top-module to correctly handle absolute paths. (#8249, fixes #7370, @Alizter)

• subst: ignore broken symlinks when looking at source files (#9810, fixes #9593, @emillon)

• subst: do not fail on 32-bit systems when large files are encountered. Just log a warning in this case. (#9811, fixes #9538, @emillon)

• boot: sort directory entries in readdir. This makes the dune binary reproducible in terms of filesystem order. (#9861, fixes #9794, @emillon)

Fixed

• Revert to outputing a file (without content) when rendering a hidden compilation unit. This fixes cases where the dune rules would fail. (@panglesd, #1069)