The type for a test that evaluated a mutant, by its path: the names of its groups, the outermost first, and then its own, as ["arithmetic"; "adds"].

The type for verdicts. A survivor always names a reaching test, because a mutant that no test reached is Outside_tests or Unreached.

survived ts is the Survived verdict whose reaching tests are ts, sorted and without duplicates. Raises Invalid_argument if ts is empty.

The type for the record of one mutant. A record is self-describing: it carries the two renderings that a report draws the mutant with, so a report needs no catalogue and outlives the executable that produced it.

record_of_mutant m v is the record of m with the verdict v. m.dismissed is dropped.

The type for verdict collections: finite maps from Mutate.id to record, ordered by Mutate.compare_id. They are immutable.

empty is the collection with no record.

add t r is t with r recorded. A Survived verdict is sorted on its way in. When t already holds a record under r.id, the smaller (before, after) pair in lexicographic order is kept, and the two verdicts combine into the verdict of a mutant that one executable saw one way and another the other way. It is Killed if either is. Otherwise it is Not_evaluated if either is, then Survived with the reaching tests of both if either is, then Outside_tests if either is, and Unreached if both are.

add checks nothing of r.id. It accepts an empty file, a line below 1, a negative col and a rewrite outside Mutate.rewrites, and load then refuses the file that save writes for the collection.

records t is the records of t, ordered by Mutate.compare_id.

merge a b is the union of a and b, where two records that share an identifier are combined as add does. merge is commutative, associative and idempotent, empty is its unit, and an Unreached verdict leaves the verdict it is combined with unchanged, so merging any number of files in any order gives one answer.

The type for the errors of reading a verdict file, which is Instr.error, where each case is described.

pp_error ppf e is Instr.pp_error format ppf e.

The type for the identity of the writer of a verdict file, which is Instr.identity.

format is the constants of the .mutants format: the magic line above, the data directory mutants, the extension mutants and the kind verdict.

writer_identity ~exe is the identity to record for the executable at exe, whose exe is Instr.exe_identity ~exe, or None when exe cannot be read.

output_file ~exe is Instr.output_file format ~exe, the one verdict file of the executable at exe. An executable that is renamed or moved leaves its previous file behind.

load path is Ok (t, identity) when the file at path is a verdict file, where identity is the recorded writer, if any. The file is read with Instr.read_file, and every error names path. Otherwise it is the error of the read, Error (Unknown_format _) for another first line, or Error (Corrupt _) for data that is truncated or invalid:

• a negative count, or a count larger than the input,
• an empty file name, a line below 1 or a negative column,
• a rewrite outside Mutate.rewrites, or an unknown verdict,
• a survivor with no reaching test, or a second record for one identifier,
• a malformed identity line, or bytes after the last record.

Nothing is repaired, and a file with one malformed record is not read at all.

save ?identity path t writes t to path in the format of a verdict file, with Instr.write_file. Records are ordered by Mutate.compare_id and reaching tests are sorted, so equal collections give equal files. identity is recorded after the magic line when it is given. A merged collection has no single writer and is written without one.

load path is then Ok (t, identity) for every t whose identifiers load accepts, and Error (Corrupt _) for any other (see add). A collection built from the mutants of Mutate.catalogue round-trips, unless a source file was registered under the name "".

Raises Invalid_argument before anything is written if identity.exe is empty or if identity.digest is not 32 lowercase hexadecimal digits, and Sys_error if the file cannot be written.