OCaml Changelog


Read the latest releases and updates from the OCaml ecosystem.

Dune 3.16.0

We're happy to announce the release of Dune 3.16.0.

Among the list of chances, this release contains improvements to Melange support and a way to look for references in a whole project using Merlin and OCaml LSP.

See full changelog


  • 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)


  • 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)


  • 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)

Dune 3.15.3

We just released version 3.15.3 with some bug fixes.

See full changelog


  • 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)

Dune 3.15.2

We just released version 3.15.2 with some bug fixes.

This one is particularly important for Coq users since it fixes a bug introduced in 3.13.0 that made incremental builds very slow.

See full changelog


  • 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)

Dune 3.15.0

We're happy to announce that Dune 3.15.0 is now available. This feature has many fixes and new features that you can find in the changelog.

There are a few new features that we would like to specially highlight.

Removal of previous limitations in many forms

Prior to Dune 3.15 there were a number of limitations where percent forms like %{env:...} could be used to expand to useful values. In this release, @rgrinberg put some effort to relax a lot of these restrictions where possible.

In the new version some of these limitations have been lifted, so for example {env:...} can be used in install stanzas (#10160).

Likewise there was no consistency where %{cma:...} or %{cmo:...} could be used. With #10169, these forms should work consistently everywhere.

Similarly the variables allowed in enabled_if fields have been expanded in #10250, from just allowing variables that can be computed from the context to now allowing all variables as long as expanding these variables does not introduce dependency cycles.

These relaxed rules can also be combined to enable a library depending on environment variables, e.g. (enabled_if %{env:ENABLE_LIBFOO=false})).

Overlapping names in different contexts

Continuing the theme of conditionally enabling or disabling code to be built, @jchavarri and @rgrinberg's work on #10220 makes it possible to have overlapping names between executable and melange.emit targets. This can be useful when a name is to be shared in different contexts (e.g. one context with native compilation and one emitting code for the browser).

Properly output UTF-8 encoded text when formatting

Dune does not assume an encoding of dune files, however when files were formatted the formatter would err on the safe side and escape bytes outside the ASCII range. This means that UTF-8 characters outside of ASCII would get escaped into decimal escape sequences.

This was especially annoying in places where the user would write natural language texts, which is common when defining Opam packages in dune-project files. For example a discussion of a paper by Paul Erdős, Peter Frankl, Vojtěch Rödl would upon reformatting be turned into Paul Erd\197\145s, Peter Frankl, Vojt\196\155 R\195\182, which does a disservice to these scientists and is hard to read.

Thanks to the work of @moyodiallo in #9728 starting with Dune 3.15 the original encoding will be preserved, so your package descriptions will be more readable.

See full changelog


  • 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)


  • 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)


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

Dune 3.14.2

We're happy to announce that Dune 3.14.2 is now available.

Note that due to a regression that was detected before publishing to opam version 3.14.1 should not be used. The fix for the regression is part of this release.

This feature brings some small bugfixes around the handling of Coq as well as solves an issue where Dune is running on Windows in a path that contains Unicode characters. This affected e.g. users with diacritics or non-latin script in their name when running Dune within their home directory.

See full changelog


  • 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)

Dune 3.14.0

We're happy to announce that Dune 3.14.0 is now available. This feature has many fixes and new features that you can find in the changelog.

There are a few new features that we would like to specially highlight.

Dynamic dune files with (dynamic_include)

It is common for some parts of a build to be dynamic: for example a source file can be generated, or some parts of the configuration like C flags can be generated from a Dune rule. But until now it was not possible to generate rules dynamically.

For example, one might want to do it is to set up one rule per input file. This is a common pattern in test suites and is easy to do with Make. But Dune does not have a concept of parameterized rules, so it is necessary to set up one rule per input file.

The pattern to do this with Dune is to:

  • Write a generator that lists the input files and emits Dune stanzas (as text);
  • Add a rule that makes a dune.inc file using this generator;
  • Add (include dune.inc) in the main dune file,

However, this requires checking in the generated dune.inc file in the repository. Another drawback is that when modifying the list of input files, it is necessary to run tests twice: one to update dune.inc, one to run the new test.

This release of Dune adds a new (dynamic_include) stanza that lifts these restrictions: dune.inc does not have to be part of the source tree, it can be generated transparently. This comes with some restrictions: some stanzas can not be generated, in particular the ones that define public libraries. And due to how rule loading works, the generated stanza needs to be defined in a different directory.

Still, this should be useful for many users that rely on the generate-include-commit pattern described above.

Sherlodoc integration

Sherlodoc is a search engine for OCaml documentation, which supports search by name, documentation and fuzzy type search (similar to Hoogle in the Haskell world). It can be obtained from opam using opam install sherlodoc.

When it is available, Dune commands that produce HTML documentation, such as dune build @doc and dune build @doc-new, will include a search bar in the generated output.

See full changelog


  • 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)


  • 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)


  • 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)

Dune 3.13.1

We just released version 3.13.1 with some bugfixes.

See full changelog
  • 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)

Dune 3.13.0

We're happy to announce that Dune 3.13.0 is now available. This feature is packed with fixes and new features that you can find in the changelog.

There are a few new features that we would like to specially highlight.

Generate Conflicts File for Menhir Grammars (#9512, @nojb)

When menhir is used to generate code from .mly files, there are sometimes issues with the grammar itself, such as shift-reduce conflicts.

Menhir has an option to generate a "conflicts" file using its --explain flag, but until now this was not exposed by Dune. Starting from this version, this file will be generated automatically to help developers debug their grammars.

Cached Directory Targets (#9535, @rleshchinskiy)

Dune's global cache is a way to save the result of intermediate build results, even across projects. Previously, it would only work with file targets. With this change, it now supports Dune's experimental directory targets.

Dynamic Module List (#9578, @nojb)

In several places in the Dune language, it is possible to pass a list of modules. For example in a (library) stanza, if for some reason the default of picking all the source files in the current directory is not the right thing to do, it is possible to pass (module A B C) to only attach these modules to the library.

An important limitation has been that the list of modules needed to be static: written as is in the dune file. This limitation has now been lifted and it is possible to use (:include) or %{read-lines:file} in this field and similar ones.

LexiFi's use case is a system of static plug-ins: a program is extended by selecting which modules are linked to the application core. This list of modules can now be emitted by a generator that reads a configuration file.

Previously, this required using OCaml syntax for the dune file, which has several issues, including incompatibility with features like (include_subdirs) and poor performance because Dune does not know the dependencies of the generator and needs to re-run the build more times than necessary.

See full changelog


  • Add command dune cache clear to completely delete all traces of the Dune cache. (#8975, @nojb)

  • Allow to disable Coq 0.8 deprecation warning (#9439, @ejgallego)

  • Allow OCAMLFIND_TOOLCHAIN to be set per context in the workspace file through the env stanza. (#9449, @rgrinberg)

  • Menhir: generate .conflicts file by default. Add new field to the (menhir) stanza to control the generation of this file: (explain <blang expression>). Introduce (menhir (flags ...) (explain ...)) field in the (env) stanza, delete (menhir_flags) field. All changes are guarded under a new version of the Menhir extension, 3.0. (#9512, @nojb)

  • Directory targets can now be cached. (#9535, @rleshchinskiy)

  • It is now possible to use special forms such as (:include) and variables %{read-lines:} in (modules) and similar fields. Note that the dependencies introduced in this way (i.e., the files being read) must live in a different directory than the stanza making use of them. (#9578, @nojb)

  • Remove warning 30 from default set for projects where dune lang is at least 3.13 (#9568, @gasche)

  • Add coqdoc_flags field to coq field of env stanza, allowing the setting of workspace-wide defaults for coqdoc_flags. (#9280, fixes #9139, @Alizter)

  • ctypes: fix an error where (ctypes) with no (function_description) would cause an error trying refer to a nonexistent _stubs.a dependency (#9302, fix #9300, @emillon)


  • Check that package names in (depends) and related fields in dune-project are well-formed. (#9472, fixes #9270, @ElectreAAS)


  • Do not ignore (formatting ..) settings in context or workspace files (#8447, @rgrinberg)

  • Fixed a bug where Dune was incorrectly parsing the output of coqdep when it was escaped, as is the case on Windows. (#9231, fixes #9218, @Alizter)

  • Copying mode for sandboxes will now follow symbolic links (#9282, @rgrinberg)

  • Forbid the empty (binaries ..) field in the env stanza in the workspace file unless language version is at least 3.2. (#9309, @rgrinberg)

  • [Coq] Fix bug in computation of flags when composed with boot theories. (#9347, fixes #7909, @ejgallego)

  • Fixed a bug where the (select) field of the (libraries) field of the (test) stanza wasn't working properly. (#9387, fixes #9365, @Alizter)

  • Fix handling of the PATH argument to dune init proj NAME PATH. An intermediate directory called NAME is no longer created if PATH is supplied, so dune init proj my_project . will now initialize a project in the current working directory. (#9447, fixes #9209, @shonfeder)

  • Experimental doc rules: Correctly handle the case when a package depends upon its own sublibraries (#9461, fixes #9456, @jonludlam)

  • Resolve various public binaries to their build location, rather than to where they're copied in the _build/install directory (#9496, fixes #7908, @rgrinberg).

  • Correctly ignore warning flags in vendored projects (#9515, @rgrinberg)

  • Use watch exclusions in watch mode on MacOS (#9643, fixes #9517, @PoorlyDefinedBehaviour)

  • Fix Merlin configuration for (include_subdirs qualified) modules (#9659, fixes #8297, @rgrinberg)

  • Fix handling of enabled_if in binary install stanzas. Previously, we'd ignore the result of enabled_if when evaluating %{bin:..} (#9707, @rgrinberg)

Dune 3.12.2

We just released version 3.12.2 with 2 bugfixes.

See full changelog


  • Fix version check in runtest_alias for cram stanza (#9454, @emillon)

  • Fix stack overflow when a (run) action can not be parsed. (#9530, fixes #9529, @gridbugs)

Dune 3.12.1

We're pleased to announce the release of Dune 3.12!

Note that due to a mistake during the release process, version 3.12.0 was not published to opam and should not be used.

This version contains many fixes but we would like to highlight the following features:

  • dune ocaml doc is a new command that will build the docs of your package, and open them in a web browser directly.
  • a new set of odoc rules will build documentation for the whole switch. It can be invoked by dune build @doc-new. Note that this is still experimental.
  • Dune can now be built and installed on Haiku.
See full changelog


  • Introduce $ dune ocaml doc to open and browse documentation. (#7262, fixes #6831, @EmileTrotignon)

  • dune cache trim now accepts binary byte units: KiB, MiB, etc. (#8618, @Alizter)

  • Introduce the runtest_alias field to the cram stanza. This allows removing default runtest alias from tests. (@rgrinberg, #8887)

  • Display cache location in Dune log (#8974, @nojb)

  • Dune can now be built and installed on Haiku (#8795, fix #8551, @Alizter)

  • Mark installed directories in dune-package files. This fixes (package) dependencies against packages that contain such directories. (#8953, fixes #8915, @emillon)

  • Introduce new experimental odoc rules (#8803, @jonjudlam)


  • dune-build-info: when version="" is found in a META file, we now return None as a version string (#9177, @emillon)

  • No longer force colors for OCaml 4.03 and 4.04 (#8778, @rgrinberg)

  • Dependencies in the copying sandbox are now writeable (#8920, @rgrinberg)

  • Rules that only use internal dune actions (write-file, echo, etc.) can now be sandboxed. (#9041, fixes #8854, @rgrinberg)

  • Add test_ prefix to default test name in dune init project (#9257, fixes #9131, @9sako6)


  • Do not ignore libraries named bigarray when they are defined in conjunction with OCaml 5.0 (#8902, fixes #8901, @rgrinberg)

  • Correctly ignore bigarray on recent versions of OCaml (#9076, @rgrinberg)

  • Absent packages shouldn't prevent all rules from being loaded (#8948, fixes #8630, @rgrinberg)

  • Correctly determine the stanza of menhir modules when (include_subdirs qualified) is enabled (@rgrinberg, #8949, fixes #7610)

  • Re-run actions whenever (expand_aliases_in_sandbox) changes (#8990, @rgrinberg)

  • Do not re-run rules when their location changes (#9052, @rgrinberg)

  • [coq rules] Be more tolerant when coqc --print-version / --config don't work properly, and fallback to a reasonable default. This fixes problems when building Coq projects with (stdlib no) and likely other cases. (#8966, fix #8958, @Alizter, reported by Lasse Blaauwbroek)

  • Dune will now run at a lower framerate of 15 fps rather than 60 when INSIDE_EMACS. (#8812, @Alizter)

Dune 3.11.1

Following the release of Dune 3.11.0 a few days ago, we've just released version 3.11.1 with a couple of bug fixes:

  • Fix the dune rpc status command that was incorrectly showing that there were no RPC servers running on Windows.
  • Fix a bogus error when no inline test was declared in a library using (inline_tests).
See full changelog


  • Fix dune rpc commands on Windows (#8806, fixes #8799, @nojb)

  • Fix inline_tests when the partition list is empty (#8849, fixes #8848, @hhugo)

Dune 3.11.0

We're pleased to announce the release of Dune 3.11!

Here are some highlights from this release.

Dune Terminal User Interface (TUI)

The biggest highlight in this release is the introduction of the new Terminal User Interface (TUI) display mode.

You can now run dune build --display tui to open a TUI. We recommend using it in conjunction with Dune watch mode (dune build -w --display tui).

From the TUI, you will be able to navigate messages from Dune build, scroll through them, or click to minimize them. Press ? to show the help screen.

Installing Source Directories

Another exciting feature in this release is the new (source_trees ..) field added to the (install ..) stanzas to add every files in a directory to the installation. For instance, to add your manual to the installation, you can use:

 (section doc)
 (source_trees manual))

Let us know what you think about these features, and don't hesistate to open issues on Dune's bug tracker if you encounter any issue.

See full changelog


  • enabled_if now supports arch_sixtyfour variable (#8023, fixes #7997, @Alizter)

  • Experimental: Added a $ dune monitor command that can connect to a running dune build in watch mode and display the errors and progress. (#8152, @Alizter)

  • The progress RPC procedure now has an extra field for the In_progress constructor for the number of failed jobs. (#8212, @Alizter)

  • Add a --preview flag to dune fmt which causes it to print out the changes it would make without applying them (#8289, @gridbugs)

  • Introduce (source_trees ..) to the install stanza to allow installing entire source trees. (#8349, @rgrinberg)

  • Add --stop-on-first-error option to dune build which will terminate the build when the first error is encountered. (#8400, @pmwhite and @Alizter)

  • Dune now displays the number of errors when waiting for changes in watch mode. (#8408, fixes #6889, @Alizter)

  • Add with_prefix keyword for changing the prefix of the destination of installed files matched by globs. (#8416, @gridbugs)

  • Added experimental --display tui option for Dune that opens an interactive Terminal User Interface (TUI) when Dune is running. Press '?' to open up a help screen when running for more information. (#8429, @Alizter and @rgrinberg)

  • Add a warnings field to dune-project files as a unified mechanism to enable or disable dune warnings (@rgrinberg, 8448)

  • dune exec: support syntax like %{bin:program}. This can appear anywhere in the command line, so things like dune exec time %{bin:program} now work. (#6035, #8474, fixes #2691, @emillon, @Leonidas-from-XIV)

  • Add a new alias @doc-json to build odoc documentation in JSON format. This output can be consumed by external tools. (#8178, @emillon)

Changed and Fixed

  • Use posix_spawn instead of fork on MacOS. This gives us a performance boost and allows us to re-enable thread. (#8090, @rgrinberg)

  • Modules that were declared in (modules_without_implementation), (private_modules) or (virtual_modules) but not declared in (modules) will raise an error. (#7674, @Alizter)

  • No longer emit linkopts(javascript) in META files (#8168, @hhugo)

  • RPC message styles are now serialised meaning that RPC diagnostics keep their ANSI styling. (#8516, fixes #6921, @Alizter)

  • Truncate output from actions that produce too much output (@tov, #8351)

  • Allow libraries to shadow OCaml built-in libraries. Previously, built-in libraries would always take precedence. (@rgrinberg, #8558)

  • dune utop no longer links utop in "custom" mode, which should make this command considerably faster. (#8631, fixes #6894, @nojb)

  • Ensure that package names in dune-project are valid opam package names. (#8331, @emillon)

  • init: check that module names are valid (#8644, fixes #8252, @emillon)

  • dune init: parse --public as a public name (#8603, fixes #7108, @emillon)

  • Stop signing source files with substitutions. Sign only binaries instead (#8361, fixes #8360, @anmonteiro)

  • Make copy sandbox support directory targets. (#8705, fixes #7724, @emillon)

Deprecated and Removed

  • Deprecate install destination paths beginning with ".." to prevent packages escaping their designated installation directories. (#8350, @gridbugs)

  • Remove warning against .dune files generated by pre Dune 2.0 (#8611, @rgrinberg)

  • Remove versions 0.1 and 0.2 of the experimental ctypes extension. (#8293, @emillon)

Dune 3.9.3

The fix to sendfile in 3.9.2 was not quite enough so here is the last part of the fix. It brings compatibility with filesystems where sendfile is not available, in particular when ecryptfs is used.

See full changelog


  • Fix flushing when using sendfile fallback (#8288, fixes #8284, @alan-j-hu)

Dune 3.10.0

We're happy to announce the release of Dune 3.10.0. It comes with some internal fixes as well as some interesting features:

  • some changes in dune describe that will allow a better implementation of opam-dune-lint to check the consistency between library and package dependencies
  • more commands made available under dune show for a more consistent command line interface
See full changelog


  • Add dune show rules as alias of the dune rules command. (#8000, @Alizter)

  • Add dune show installed-libraries as an alias of the dune installed-libraries command. (#8135, @Alizter)

  • Add dune build --dump-gc-stats FILE argument to dump garbage collection stats to a named file. (#8072, @Alizter)

  • Add dune describe package-entries to print all package entries (#7480, @moyodiallo)


  • Fix %{deps} to expand properly in (cat ...) when containing 2 or more items. (#8196, @Alizter)

  • Fix the severity of error messages sent over RPC which was missing. (#8193, @Alizter)

  • Fix bug with ppx and Reason syntax due to missing dependency in sandboxed action (#7932, fixes #7930, @Alizter)


  • Improve dune describe external-lib-deps by adding the internal dependencies for more information. (#7478, @moyodiallo)

  • Re-enable background file digests on Windows. The files are now open in a way that prevents race condition around deletion. (#8262, fixes #8268, @emillon)

Dune 3.9.2

This bugfix-only release contains two platform-specific changes: one fixes the Dune cache on Windows, and the other one completes the fix on Linux when sendfile is not available. This makes Dune available where user directories are encrypted using ecryptfs for example.

See full changelog


  • Disable background digests on Windows. This prevents an issue where unremovable files would make Dune crash when the shared cache is enabled. (#8243, fixes #8228, @emillon)

  • Fix permission errors when sendfile is not available (#8234, fixes #8210, @emillon)

Dune 3.9.1

In Dune 3.9.0, we added a feature that offloads some computations to background threads. Unfortunately, this has a bad interaction on macOS, where we fork processes to implement the RPC server and watch mode.

We marked Dune 3.9.0 unavailable on macOS, and released 3.9.1 with some mitigations: we don't offload these computations on macOS, and we only fork when necessary.

The plan for the next release is to stop forking processes on macOS.

See full changelog


  • Disable background operations and threaded console on macOS and other Unixes where we rely on fork. (#8100, #8121, fixes #8083, @rgrinberg, @emillon)

  • Initialize async I/O thread lazily. (#8122, @emillon)

Dune 3.9.0

The Dune team is thrilled to announce the release of Dune 3.9.0. This version ships with a host of new features and improvements, including:

  • New dune show Command: This command enables you to display various pieces of information. For instance, you can use dune show pp to display the preprocessed output of a file or dune show aliases [DIR] to list the aliases available in DIR. Read more about the command on its manpage using dune show --help.
  • Improved Dialect Support: We have rolled out several fixes related to dialect support. These changes make it easier to work with Dream's .eml files.
  • Introduction of (build_if) Toggle in (test) Stanza: This new field facilitates the packaging of non-portable tests and benchmarks. If you have tests that don't build on a specific platform, you can now tell Dune not to build them on other Platforms with the build_if field.

Enjoy the new features and improvements incorporated into this version!

See full changelog


  • Include the time it takes to read/write state files when --trace-file is enabled (#7960, @rgrinberg)

  • Include source tree scans in the traces produced by --trace-file (#7937, @rgrinberg)

  • Add --all option to dune rpc status to show all Dune RPC servers running. (#8011, fix #7902, @Alizter)

  • Add additional metadata to the traces provided by --trace-file whenever --trace-extended is passed (#7778, @rleshchinskiy)

  • $ dune describe is now a command group, so arguments to subcommands must be passed after subcommand itself. (#7919, @Alizter)

  • Add dune show command group which is an alias of dune describe. (#7946, @Alizter)

  • Add dune show env command and make dune printenv an alias of it. (#7985, @Alizter)

  • Add commands dune show targets and dune show aliases that display all the available targets and aliases in a given directory respectively. (#7770, grants #265, @Alizter)

  • Extensions used in (dialect) can contain periods (e.g., cppo.ml). (#7782, fixes #7777, @nojb)

  • The interface and implementation fields of a (dialect) are now optional (#7757, @gpetiot)

  • Add (build_if) to the (test) stanza. When it evaluates to false, the executable is not built. (#7899, fixes #6938, @emillon)

  • Allow (include_subdirs qualified) to be used when libraries define a (modules ...) field (#7797, fixes #7597, @anmonteiro)

  • Allow multiple globs in library's (stdlib (internal_modules ..)) (@anmonteiro, #7878)


  • Do not rerun OCaml syntax files on every iteration of the watch mode. This is too memory consuming. (#7894, fix #6900, @rgrinberg)

  • Attach melange rules to the default alias (#7926, @haochenx)

  • Compute digests and manage sandboxes in background threads (#7947, @rgrinberg)


  • Validate file extension for $ dune ocaml top-module. (#8005, fixes #8004, @3Rafal)

  • Cinaps: The promotion rules for cinaps would only offer one file at a time no matter how many promotions were available. Now we offer all the promotions at once (#7901, @rgrinberg)

  • Add necessary parentheses in generated opam constraints (#7682, fixes #3431, @Lucccyo)


  • Remove some compatibility code for old version of dune that generated .merlin files. Now dune will never remove .merlin files automatically (#7562)

  • In opam constraints, reject (and) and (or) with no arguments at parse time (#7730, @emillon)

Dune 3.8.3

This point release fixes two important issues on Windows and Linux.

See full changelog
  • Fix deadlock on Windows (dune#8044, @nojb)
  • When using sendfile to copy files on Linux, fall back to the portable version if it fails at runtime for some reason (NFS, etc). (dune#8049, fixes dune#8041, @emillon)

Dune 3.8.2

We've released Dune 3.8.2 with a few bug fixes.

See full changelog
  • Switch back to threaded console for all systems; fix unresponsive console on Windows (dune#7906, @nojb)
  • Respect -p / --only-packages for melange.emit artifacts (dune#7849, @anmonteiro)
  • Fix scanning of Coq installed files (@ejgallego, reported by @palmskog, dune#7895 , fixes dune#7893)
  • Fix RPC buffer corruption issues due to multi threading. This issue was only reproducible with large RPC payloads (dune#7418)
  • Fix printing errors from excerpts whenever character offsets span multiple lines (dune#7950, fixes dune#7905, @rgrinberg)

Dune 3.8.1

We've just released a patch version of Dune to fix regressions introduced in Dune 3.8.0.

In particular, we've reverted some cross-compilation improvements that caused build failures when using ppx_runtime_libraries and we'll revisit them in a future version of Dune.

See full changelog
  • Fix a crash when using a version of Coq < 8.13 due to the native compiler config variable being missing. We now explicitly default to (mode vo) for these older versions of Coq. (dune#7847, fixes dune#7846, @Alizter)
  • Duplicate installed Coq theories are now allowed with the first appearing in COQPATH being preferred. This is inline with Coq's loadpath semantics. This fixes an issue with install layouts based on COQPATH such as those found in nixpkgs. (dune#7790, @Alizter)
  • Revert dune#7415 and dune#7450 (Resolve ppx_runtime_libraries in the target context when cross compiling) (dune#7887, fixes dune#7875, @emillon)

Dune 3.8.0

The dune team is pleased to announce the release of Dune 3.8.0.

It is now available in opam-repository. As usual, it should always be safe to upgrade your dune package: new features and deprecations are only available if you upgrade the language version in your dune-project files.

🌟 Spotlight Features

  1. Dune concurrent action

Dune 3.8.0 introduced the new concurrent action. You can now use it instead of the progn action to execute actions concurrently.

For instance:

  (write-file A "I am file A.\n")
  (write-file B "I am certainly file B.\n")
  (write-file C "I am most certainly file C.\n"))))

will write to files A, B and C concurrently.

  1. Support for .mld files

In Dune 3.7.0, we introduced version 0.3 of the mdx stanza, which came with support for .mld files.

In Dune 3.8.0, .mld files are now supported by default with version 0.4 of the mdx stanza!

Have a look at this diff to see how to migrate your code to the new stanza version.

See full changelog


  • Introduce mdx stanza 0.4 requiring mdx >= 2.3.0 which updates the default list of files to include *.mld files (#7582, @Leonidas-from-XIV)

  • Allow (stdlib ...) to be used with (wrapped false) in library stanzas (#7139, @anmonteiro).

  • Allow the main module of a library with (stdlib ...) to depend on other libraries (#7154, @anmonteiro).

  • Support (link_flags ...) in (cinaps ...) stanza. (#7423, fixes #7416, @nojb)

  • Allow (package ...) in any position within (rule ...) stanza (#7445, @Leonidas-from-XIV)

  • Added a new user action (concurrent ) which is like (progn ) but runs the actions concurrently. (#6933, @Alizter)

  • Accept the Ordered Set Language for the modes field in library stanzas (#6611, @anmonteiro).

  • Allow parallel execution of inline tests partitions (#7012, @hhugo)

  • Add the --display-separate-messages flag to separate the error messages produced by commands with a blank line. (#6823, fixes #6158, @esope)

  • Add --watch-exclusions to Dune build options (#7216, @jonahbeckford)

  • Adds support for loading plugins in toplevels (#6082, fixes #6081, @ivg, @richardlford)

  • Introduce a public_headers field on libraries. This field is like install_c_headers, but it allows to choose the extension and choose the paths for the installed headers. (#7512, @rgrinberg)

  • Dune can now detect Coq theories from outside the workspace. This allows for composition with installed theories (not necessarily installed with Dune). (#7047, @Alizter, @ejgallego)

  • Added a --no-build option to dune coq top for avoiding rebuilds (#7380, fixes #7355, @Alizter)

  • Add a coqdoc_flags field to the coq.theory stanza allowing the user to pass extra arguments to coqdoc. (#7676, fixes #7954 @Alizter)

  • Preliminary support for Coq compiled intefaces (.vos files) enabled via (mode vos) in coq.theory stanzas. This can be used in combination with dune coq top to obtain fast re-building of dependencies (with no checking of proofs) prior to stepping into a file. (#7406, @rlepigre)

  • Read pkg-config arguments from the PKG_CONFIG_ARGN environment variable (#1492, #7734, @anmonteiro)

  • Use $PKG_CONFIG, when set, to find the pkg-config binary (#7469, fixes #2572, @anmonteiro)


  • Bootstrap: remove reliance on shell. Previously, we'd use the shell to get the number of processors. (#7274, @rgrinberg)

  • Non-user proccesses such as version control or config checking are now run silently. (#6994, fixes #4066, @Alizter)

  • Bytecode executables built for JSOO are linked with -noautolink and no longer depend on the shared stubs of their dependent libraries (#7156, @nojb)

  • Always include opam files in the generated .install file. Previously, it would not be included whenever (generate_opam_files true) was set and the .install file wasn't yet generated. (#7547, @rgrinberg)


  • Modules that were declared in (modules_without_implementation), (private_modules) or (virtual_modules) but not declared in (modules) will cause Dune to emit a warning which will become an error in 3.9. (#7608, fixes #7026, @Alizter)

  • Coq language versions less 0.8 are deprecated, and will be removed in an upcoming Dune version. All users are required to migrate to (coq lang 0.8) which provides the right semantics for theories that have been globally installed, such as those coming from opam (@ejgallego, @Alizter)


  • Find pps dependencies in the host context when cross-compiling, (#7415, fixes #4156, @anmonteiro)

  • Fix plugin loading with findlib. The functionality was broken in 3.7.0. (#7556, @anmonteiro)

  • Load the host context findlib.conf when cross-compiling (#7428, fixes #1701, @rgrinberg, @anmonteiro)

  • Allow overriding the ocaml binary with findlib configuration (#7648, @rgrinberg)

  • Resolve ppx_runtime_libraries in the target context when cross compiling (#7450, fixes #2794, @anmonteiro)

  • Fix dune install when cross compiling (#7410, fixes #6191, @anmonteiro, @rizo)

  • Fix string quoting in the json file written by --trace-file (#7773, @rleshchinskiy)

  • Correctly set MANPATH in dune exec. Previously, we would use the bin/ directory of the context. (#7655, @rgrinberg)

  • merlin: ignore instrumentation settings for preprocessing. (#7606, fixes #7465, @Alizter)

  • When a rule's action is interrupted, delete any leftover directory targets. This is consistent with how we treat file targets. (#7564, @rgrinberg)

  • Fix dune crashing on MacOS in watch mode whenever $PATH contains $PWD (#7441, fixes #6907, @rgrinberg)

  • Dune in watch mode no longer builds concurrent rules in serial (#7395 @rgrinberg, @jchavarri)

  • dune coq top now correctly respects the project root when called from a subdirectory. However, absolute filenames passed to dune coq top are no longer supported (due to being buggy) (#7357, fixes #7344, @rlepigre and @Alizter)

  • RPC: Ignore SIGPIPE when clients suddenly disconnect (#7299, #7319, fixes #6879, @rgrinberg)

  • Always clean up the UI on exit. (#7271, fixes #7142 @rgrinberg)

  • Bootstrap: correctly detect the number of processors by allowing nproc to be looked up in $PATH (#7272, @Alizter)

  • Speed up file copying on macos by using clonefile when available (@rgrinberg, #7210)

  • Support commands that output 8-bit and 24-bit colors in the terminal (#7188, @Alizter)

  • Speed up rule generation for libraries and executables with many modules (#7187, @jchavarri)

  • Do not re-render UI on every frame if the UI doesn't change (#7186, fix #7184, @rgrinberg)

  • Make coq_db creation in scope lazy (@ejgallego, #7133)

  • dune install now respects --display quiet mode (#7116, fixes #4573, fixes #7106, @Alizter)

  • Stub shared libraries (dllXXX_stubs.so) in Dune-installed libraries could not be used as dependencies of libraries in the workspace (eg when compiling to bytecode and/or Javascript). This is now fixed. (#7151, @nojb)

  • Fix regression where Merlin was unable to handle filenames with uppercase letters under Windows. (#7577, @nojb)

  • On nix+macos, pass -f to the codesign hook to avoid errors when the binary is already signed (#7183, fixes #6265, @greedy)

  • Fix bug where RPC clients built with dune-rpc-lwt would crash when closing their connection to the server (#7581, @gridbugs)

  • Fix RPC server on Windows (used for OCaml-LSP). (#7666, @nojb)

Dune 3.7.1

We are excited to announce the release of Dune 3.7.1, which brings a few bug fixes from the recent 3.7.0 release:

  • Resolved watch mode issue for executables on macOS: We have addressed a problem with the recently introduced watch mode for executables that was causing segmentation faults on macOS. Users can now enjoy a stable watch mode without unexpected crashes on macOS.
  • Fixed "Too many links" error on Windows: We have fixed an issue that caused Dune build failures with a "Too many links" error on Windows when using Dune cache.

... and a few more, you can consult the changelog for a full list of bug fixes.

See full changelog
  • Fix segfault on MacOS when dune was being shutdown while in watch mode. (#7312, fixes #6151, @gridbugs, @emillon)

  • Fix preludes not being recorded as dependencies in the (mdx) stanza (#7109, fixes #7077, @emillon).

  • Pass correct flags when compiling stdlib.ml. (#7241, @emillon)

  • Handle "Too many links" errors when using Dune cache on Windows. The fix in 3.7.0 for this same issue was not effective due to a typo. (#7472, @nojb)

Dune 3.7.0

The dune team is pleased to announce the release of Dune 3.7.0.

As in the previous announce, here is a changelog split in several parts: changes to the dune executable itself (new commands or options, etc) and changes to the dune language. Most of the changes to the latter are only enabled when you opt-in to the new version by specifying (lang dune 3.7) in the corresponding dune-project file. In other words, it should always be safe to upgrade the dune package.

🌟 Spotlight Features

  1. Watch mode for executables

Dune 3.7 now supports watch mode for executables! 🎉

It works just as you'd expect, if you define an executable, you can run it with

dune exec -w my-executable

It will interrupt the process when a file change and re-start the application.

For a practical example of the workflows enabled by watch-mode, check this demo of a live reload for web development:

  1. Native Windows Polling

Starting from Dune 3.7, Dune watch mode is now available on Windows!

@yams-yams and @nojb from Lexifi have been working on integrating Windows native polling API with Dune to supplement the support for fswatch, which is unavailable on Windows.

Windows users can now run dune build -w out of the box!

  1. Qualified Subdirs

It's quite common to organise your code into subdirectories to separate components. Until now, you could do this by including (include_subdirs unqualified) in your dune files, but this wasn't completely satisfying since all of your modules were available in the top-level. If you wanted to expose modules in subdirectories under another module, you had to create a separate library, which was.. quite the overhead.

Dune 3.7 brings support for the highly-anticipated qualified sub-directories. You can now write (include_subdirs qualified) in your dune file, and modules in your subdirectories will be exposed under a module with the name of the directory.

See full changelog

dune executable


  • Allow running $ dune exec in watch mode (with the -w flag). In watch mode, $ dune exec the executed binary whenever it is recompiled. (#6966, @gridbugs)

  • Add a dune cache size command for displaying the size of the cache (#6638, @Alizter)

  • Allow $ dune ocaml dump-dot-merlin to run in watch mode. Also this command shouldn't print "Entering Directory" mesages. (#6497, @rgrinberg)

  • Add native support for polling mode on Windows (#7010, @yams-yams, @nojb, review by @Rucikir and @jbeckford)

  • Auto-detect dune-workspace files as dune files in Emacs (#7061, @ilankri)

  • Allow $ dune utop to load libraries defined in data only directories defined using (subdir ..) (#6631, @rgrinberg)


  • Make dune describe workspace return consistent dependencies for executables and for libraries. By default, compile-time dependencies towards PPX-rewriters are from now not taken into account (but runtime dependencies always are). Compile-time dependencies towards PPX-rewriters can be taken into account by providing the --with-pps flag. (#6727, fixes #6486, @esope)

  • Use colored output with MDX when Dune colors are enabled. (#6462, @MisterDA)

  • Use colored output with GCC and Clang when compiling C stubs. The flag -fdiagnostics-color=always is added to the :standard set of flags. (#4083, @MisterDA)

  • Move $ dune ocaml-merlin -dump-config=$dir to $ dune ocaml merlin dump-config $dir. (#6547, @rgrinberg)


  • Fix parsing of OCaml errors that contain code excerpts with ... in them. (#7008, @rgrinberg)

  • Fix --trace-file output. Dune now emits a single complete event for every executed process. Unterminated async events are no longer written. (#6892, @rgrinberg)

  • Print missing newline after $ dune exec. (#6821, fixes #6700, @rgrinberg, @Alizter)

  • Fix binary corruption when installing or promoting in parallel (#6669, fixes #6668, @edwintorok)

  • Report an error if dune init ... would create a "dune" file in a location which already contains a "dune" directory (#6705, @gridbugs)

  • Fix the parsing of alerts. They will now show up in diagnostics correctly. (#6678, @rginberg)

  • Print "Leaving Directory" whenever "Entering Directory" is printed. (#6419, fixes #138, @cpitclaudel, @rgrinberg)

  • Remove "Entering Directory" messages for $ dune install. (#6513, @rgrinberg)

  • dune clean should no longer fail under Windows due to the inability to remove the .lock file. Also, bring the implementation of the global lock under Windows closer to that of Unix. (#6523, @nojb)

  • Fix missing dependencies when detecting the kind of C compiler we're using (#6610, fixes #6415, @emillon)

  • Remove spurious build dir created when running dune init proj ... (#6707, fixes #5429, @gridbugs)

  • Validate the command line arguments for $ dune ocaml top-module. This command requires one positional argument (#6796, fixes #6793, @rgrinberg)

  • Fix dependency cycle when installing files to the bin section with glob_files (#6764, fixes #6708, @gridbugs)

  • Handle "Too many links" errors when using Dune cache on Windows (#6993, @nojb)

  • Pre-emptively clear screen in watch mode (#6987, fixes #6884, @rgrinberg)

  • Allow --sandbox to affect ocamldep invocations. Previously, they were wrongly marked as incompatible (#6749, @rgrinberg)

dune language


  • Allow (include_subdirs qualified) for OCaml projects. (#6594, fixes #1084, @rgrinberg)

  • Format dune files when they are named dune-file. This occurs when we enable the alternative file names project option. (#6566, @rgrinberg)

  • Add map_workspace_root dune-project stanza to allow disabling of mapping of workspace root to /workspace_root. (#6988, fixes #6929, @richardlford)

  • Allow the cinaps stanza to set a custom alias. By default, if the alias is not set then the cinaps actions will be attached to both @cinaps and @runtest (#6991, @rgrinberg)

  • Add (using ctypes 0.3). When used, paths in (ctypes) are interpreted relative to where the stanza is defined. (#6883, fixes #5325, @emillon)


  • Stop passing -q flag in dune coq top, which allows for .coqrc to be loaded. (#6848, fixes #6847, @Alizter)

  • Coq native mode is now automatically detected by Dune starting with Coq lang 0.7. (mode native) has been deprecated in favour of detection from the configuration of Coq. (#6409, @Alizter)

  • Accurately determine merlin configuration for all sources selected with copy# and copy_files#. The old heuristic of looking for a module in parent directories is removed (#6594, @rgrinberg)


  • Fix parsing of the <= operator in blang expressions of dune files. Previously, the operator would be interpreted as <. (#6928, @tatchi)

  • Fix preprocessing with staged_pps (#6748, fixes #6644, @rgrinberg)

  • Fix the parsing of decimal and hexadecimal escape literals in dune, dune-package, and other dune s-expression based files (#6710, @shym)

  • Fix cross compilation configuration when a context with targets is itself a host of another context (#6958, fixes #6843, @rgrinberg)

  • Allow compilation rules to be impacted by (env ..) stanzas that modify the environment or set binaries. (#6527, @rgrinberg)

  • Fix handling of support files generated by odoc. (#6913, @jonludlam)

  • Fix the compilation of modules generated at link time when implicit_transitive_deps is enabled (#6642, @rgrinberg)

  • Fix inline tests with js_of_ocaml and whole program compilation mode enabled (#6645, @hhugo)

  • Fix js_of_ocaml separate compilation rules when --enable=effects ,--enable=use-js-string or --toplevel is used. (#6714, #6828, #6920, @hhugo)

  • Fix js_of_ocaml separate compilation in presence of linkall (#6832, #6916, @hhugo)

  • coqdep is now called once per theory, instead of one time per Coq file. This should significantly speed up some builds, as coqdep startup time is often heavy (#7048, @Alizter, @ejgallego)

Dune 3.6.2

See full changelog
  • Fix configurator when using the MSVC compiler (#6538, fixes #6537, @nojb)

  • Fix running the RPC server on windows (#6721 fixes #6720, @rgrinberg)

Dune 3.6.1

See full changelog
  • Fix status line enabled when ANSI colors are forced. (#6503, @MisterDA)

  • Fix build with MSVC compiler (#6517, @nojb)

  • Do not shadow library interface modules (#6549, fixes #6545, @rgrinberg)

Dune 3.6.0

Dear dune users, It is my pleasure to announce that dune 3.6.0 is now available on opam 🎉. Here's the changelog - I reused the same classification as in the previous announce for dune 3.5.0. Thanks again to all the contributors including bug reporters.

See full changelog

dune executable

This lists features of the “dune” executable itself. Upgrading dune will bring in these changes. We consider these changes safe, but it is difficult to define what a breaking change is for a command-line tool (for example, some error messages change). It is important to note that just upgrading the dune executable is not supposed to change how dune interprets existing projects. If just upgrading dune breaks compilation, it is a bug in dune, please report it!


  • Introduce a $ dune ocaml top-module subcommand to load modules directly without sealing them behind the signature. (#5940, @rgrinberg)
  • Revive $ dune external-lib-deps under $ dune describe external-lib-deps. (#6045, @moyodiallo)
  • Extend the promotion CLI to a dune promotion group: dune promote is moved to dune promotion apply (the former still works) and the new dune promotion diff command can be used to just display the promotion without applying it. (#6160, fixes #5368, @emillon)
  • Build progress status now shows number of failed jobs (#6242, @Alizter)
  • Allow promoting into source directories specified by subdir (#6404, fixes #3502, @rgrinberg)
  • Support CLICOLOR and CLICOLOR_FORCE to enable/disable/force ANSI colors. (#6340, fixes #6323, @MisterDA).
  • Create a fake socket file _build/.rpc/dune on windows to allow rpc clients to connect using the build directory. (#6329, @rgrinberg)


  • Forbid multiple instances of dune running concurrently in the same workspace. (#6360, fixes #236, @rgrinberg)
  • Make dune describe workspace return the correct root path (#6380, fixes #6379, @esope)
  • Fix running inline tests in bytecode mode (#5622, fixes #5515, @dariusf)

(lang dune 3.6)

This lists changes if you opt into the new (lang dune 3.6) version in your dune-project file. For this too, these are changes that we consider safe, but they can require changes to your dune files. For example, sandboxing is enabled in more places, which means that you might have to be more precise in expressing your dependencies. Please reach out on the issue tracker if you have trouble fixing your dune file or if something does not seem to be possible anymore.


  • Add (glob_files <glob>) and (glob_files_rec <glob>) terms to the files field of the install stanza (#6250, closes #6018, @gridbugs)
  • Allow Byte_complete binaries to be installable (#4837, @AltGr, @rgrinberg)
  • Allow :standard in the (modules) field of the coq.pp stanza (#6229, fixes #2414, @Alizter)


  • Allow absolute build directories to find public executables. For example, those specified with (deps %{bin:...}) (#6326, @anmonteiro)
  • [ctypes] do not mangle user written names in the ctypes stanza (#6374, fixes #5561, @rgrinberg)
  • Forbid private libraries with (package ..) set from depending on private libraries that don't belong to a package (#6385, fixes #6153, @rgrinberg)
  • [ctypes] always re-run pkg-config because we aren't tracking its external dependencies (#6052, @rgrinberg)
  • [ctypes] remove dependency on configurator in the generated rules (#6052, @rgrinberg)
  • Fix passing of flags to dune coq top (#6369, fixes #6366, @Alizter)
  • Prevent crash if absolute paths are used in the install stanza and in recursive globs. These cases now result in a user error. (#6331, @gridbugs)

Dune 3.5.0

I'd like to announce the release of dune 3.5.0 on opam. This release is packed with fixes and new features, that are described below with a description of what this means for project maintainers.

See full changelog

dune executable

This lists features of the "dune" executable itself. Upgrading dune will bring in these changes. We consider these changes safe, but it is difficult to define what a breaking change is for a command-line tool (for example, some error messages change). It is important to note that just upgrading the dune executable is not supposed to change how dune interprets existing projects. If just upgrading dune breaks compilation, it is a bug in dune, please report it!


  • Allow dune describe workspace to accept directories as arguments. The provided directories restrict the worskpace description to those directories. (#6107, fixes #3893, @esope)
  • Add a terminal persistence mode that attempts to clear the terminal history. It is enabled by setting terminal persistence to clear-on-rebuild-and-flush-history (#6065, @rgrinberg)


  • Fix build-info version when used with flambda (#6089, fixes #6075, @jberdine)
  • Fix compilation of Dune under esy on Windows (#6109, fixes #6098, @nojb)
  • Improve error message when parsing several licenses in (license) (#6114, fixes #6103, @emillon)
  • Handle CSI n K code in ANSI escape codes from commands. (#6214, fixes #5528, @emillon)
  • Do not ignore rules marked (promote (until-clean)) when --ignore-promoted-rules (or -p) is passed. (#6010, fixes #4401, @emillon)


  • dune install: copy files in an atomic way (#6150, @emillon)
  • update vendored copy of cmdliner to 1.1.1. This improves the built-in documentation for command groups such as dune ocaml. (#6038, @emillon, #6169, @shonfeder)
  • Extend dune describe to include the root path of the workspace and the relative path to the build directory. (#6136, @reubenrowe)

macOS support

This is technically a subset of above section. For M1 mac users, dune 3.5.0 is the first version which will correctly support dune-build-info.


  • on macOS, sign executables produced by artifact substitution (#6137, #6231, fixes #5650, fixes #6226, @emillon)
  • Enable file watching on MacOS SDK < 10.13. (#6218, @rgrinberg)


  • macOS: Handle unknown fsevents without crashing (#6217, @rgrinberg)

(lang dune 3.5)

This lists changes if you opt into the new (lang dune 3.5) version in your dune-project file. For this too, these are changes that we consider safe, but they can require changes to your dune files. For example, sandboxing is enabled in more places, which means that you might have to be more precise in expressing your dependencies. Please reach out on the issue tracker if you have trouble fixing your dune file or if something does not seem to be possible anymore.


  • Add a runtime_deps field in the cinaps stanza to specify runtime dependencies for running the cinaps preprocessing action (#6175, @rgrinberg)
  • Allow rules producing directory targets to be not sandboxed (#6056, @rgrinberg)
  • Introduce a dirs field in the install stanza to install entire directories (#5097, fixes #5059, @rgrinberg)
  • Add an (include <file>) term to the include_dirs field for adding directories to the include paths sourced from a file. (#6058, fixes #3993, @gridbugs)
  • Support (extra_objects ...) field in (executable ...) and (library ...) stanzas (#6084, fixes #4129, @gridbugs)
  • Allow rules producing directory targets to create symlinks (#6077, fixes #5945, @rgrinberg)
  • Added an (aliases ...) field to the (rules ...) stanza which allows the specification of multiple aliases per rule (#6194, @Alizter)
  • Allow include statement in install stanza (#6139, fixes #256, @gridbugs)
  • Add a new experimental feature mode_specific_stubs that allows the specification of different flags and sources for foreign stubs depending on the build mode (#5649, @voodoos)


  • Sandbox running cinaps actions starting from cinaps 1.1 (#6176, @rgrinberg)
  • Cinaps actions are now sandboxed by default (#6062, @rgrinberg)
  • Menhir rules are now sandboxed by default (#6076, @rgrinberg)
  • Inline tests are now sandboxed by default (#6079, @rgrinberg)


  • Shadow alias module Foo__ when building a library Foo (#6126, @rgrinberg)
  • Disallow generating targets in sub direcories in inferred rules. The check to forbid this was accidentally done only for manually specified targets (#6031, @rgrinberg)
  • odoc rules now about ODOC_SYNTAX and will rerun accordingly (#6010, fixes #1117, @emillon)

Coq support

These changes, associated with (lang dune 3.5), are specific to coq.


  • Add %{coq:...} macro for accessing data about the configuration about Coq. For instance %{coq:version} (#6049, @Alizter)
  • Starting with Coq build language 0.6, theories can be built without importing Coq's standard library by including (stdlib no). (#6165 #6164, fixes #6163, @ejgallego @Alizter @LasseBlaauwbroek)


  • Dune no longer considers .aux files as targets during Coq compilation. This means that .aux files are no longer cached. (#6024, fixes #6004, @alizter)
  • The test suite for Coq now requires Coq >= 8.16 due to changes in the plugin loading mechanism upstream (which now uses Findlib).
  • The (coq.theory ...) stanza will now ensure that for each declared (plugin ...), the META file for it is built before calling coqdep. This enables the use of the new Findlib-based loading method in Coq 8.16; however as of Coq 8.16.0, Coq itself has some bugs preventing this to work yet. (#6167 , workarounds #5767, @ejgallego)

Dune 3.4.1

See full changelog
  • Fix build on cygwin/i686-w64-mingw32 (#6008, @kit-ty-kate)

Dune 3.4.0

On behalf of the dune team, I’m pleased to announce the release of version 3.4.0.

Bug fixes, a couple new features, better hints and error messages - I won't restate what's in the changelog below. Thanks to everyone involved in this release!

See full changelog
  • Make dune describe correctly handle overlapping implementations for virtual libraries (#5971, fixes #5747, @esope)

  • Building the @check alias should make sure the libraries and executables don't have dependency cycles (#5892, @rgrinberg)

  • [ctypes] Add support for the errno parameter using the errno_policy field in the ctypes settings. (#5827, @droyo)

  • Fix dune coq top when it is invoked on files from a subdirectory of the directory containing the associated stanza (#5784, fixes #5552, @ejgallego, @rlepigre, @Alizter)

  • Fix hint when an invalid module name is found. (#5922, fixes #5273, @emillon)

  • The (cat) action now supports several files. (#5928, fixes #5795, @emillon)

  • Dune no longer uses shimmed META files for OCaml 5.x, solely using the ones installed by the compiler. (#5916, @dra27)

  • Fix handling of the (deps) field in (test) stanzas when there is an .expected file. (#5952, #5951, fixes #5950, @emillon)

  • Ignore insignificant filesystem events. This stops RPC in watch mode from flashing errors on insignificant file system events such as changes in the .git/ directory. (#5953, @rgrinberg)

  • Fix parsing more error messages emitted by the OCaml compiler. In particular, messages where the excerpt line number started with a blank character were skipped. (#5981, @rgrinberg)

  • env stanza: warn if some rules are ignored because they appear after a wildcard rule. (#5898, fixes #5886, @emillon)

  • On Windows, XDG_CACHE_HOME is taken to be the FOLDERID_InternetCache if unset, and XDG_CONFIG_HOME and XDG_DATA_HOME are both taken to be FOLDERID_LocalAppData if unset. (#5943, fixes #5808, @nojb)

Dune 3.3.1

See full changelog
  • Improve parsing of ocamlc errors. We now correctly strip excerpts and parse alerts (#5879, @rgrinberg)

  • The (libraries) field of the coq.theory stanza has been renamed to (plugins) and the Coq language version has been bumped to 0.5.

If you want to contribute to a new release announcement, check out the Contributing Guide on GitHub.