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fix: avoid killing process group when not applicable #12360

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Alizter merged 1 commit intoocaml:mainfrom
Alizter:dune-exec-watch-server
Feb 6, 2026
Merged

fix: avoid killing process group when not applicable #12360
Alizter merged 1 commit intoocaml:mainfrom
Alizter:dune-exec-watch-server

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@Alizter Alizter commented Aug 30, 2025

We add a way of tracking whether a job is a process group leader to the
scheduler. This allows us to avoid sending a signal to a process group
when it isn't needed.

Doing so fixes an issue with dune exec -w where rebuilds would send a
kill signal to a non-existant process group assumed to be attached to
the process we were execing.

@Alizter Alizter force-pushed the dune-exec-watch-server branch 2 times, most recently from 7f1ffff to e61a2dd Compare August 30, 2025 19:49
@Alizter Alizter force-pushed the dune-exec-watch-server branch from e61a2dd to de9aff5 Compare August 30, 2025 23:58
@rgrinberg
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I don't think we should have any "fallbacks". If we are launching a process without a process group, we know we are doing that and there's no need to send a signal to the group

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Alizter commented Aug 31, 2025

Sounds good to me. I will need to design a more principled solution that tracks the process group as you said. It might take some time before I can get round to it however.

@maiste maiste added this to the 3.21 milestone Sep 1, 2025
@Alizter Alizter force-pushed the dune-exec-watch-server branch from de9aff5 to 00984fe Compare September 1, 2025 17:55
@Alizter Alizter changed the title fix(exec-w): fallback to killing pid when pgid isn't available fix: avoid killing process group when not applicable Sep 1, 2025
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Alizter commented Sep 1, 2025

💥 I've messed up killall on Windows, the CI will not finished.

@Alizter Alizter force-pushed the dune-exec-watch-server branch from 00984fe to ca5f086 Compare September 15, 2025 23:53
@royneary
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May I ask what is missing to complete this fix? Is it just the CI failures for Windows systems?

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Alizter commented Nov 18, 2025

@royneary Windows doesn't have a direct equivalent for unix process groups and the spawn library doesn't bother tracking them in any way. The fix here appears to cause a hang on Windows that will have to be investigated.

@Alizter Alizter force-pushed the dune-exec-watch-server branch from ca5f086 to 4c5c9f5 Compare November 18, 2025 22:16
@rgrinberg
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What's not clear to me is how are we changing the behavior on windows at all here? Since there's no process groups on windows, why isn't the old code not working as before?

The issues in CI seem unrelated btw.

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Alizter commented Nov 19, 2025

@rgrinberg The issues in CI are not unrelated unfortunately. I can spin up Windows 11 in an emulator and bootstrap this branch and a normal dune build will never terminate. We are waiting for something that on windows never signals back it seems. I still don't fully understand the issue.

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Is this relevant to this issue?

Run opam exec -- make release
ocamlc -output-complete-exe -intf-suffix .dummy -g -o .duneboot.exe -I boot -I +unix unix.cma boot/types.ml boot/libs.ml boot/duneboot.ml
.\.duneboot.exe
cd _boot && D:\a\dune\dune\_opam\bin\ocamlopt.opt.exe -c -g -I +unix -I +threads -ccopt -D_UNICODE -ccopt -DUNICODE mdb.c
vendor/ocaml-lmdb\mdb.c: In function 'mdb_strerror':
vendor/ocaml-lmdb\mdb.c:1809:1: warning: function may return address of local variable [-Wreturn-local-addr]
vendor/ocaml-lmdb\mdb.c:1770:7: note: declared here

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Alizter commented Nov 19, 2025

Is this relevant to this issue?

Run opam exec -- make release
ocamlc -output-complete-exe -intf-suffix .dummy -g -o .duneboot.exe -I boot -I +unix unix.cma boot/types.ml boot/libs.ml boot/duneboot.ml
.\.duneboot.exe
cd _boot && D:\a\dune\dune\_opam\bin\ocamlopt.opt.exe -c -g -I +unix -I +threads -ccopt -D_UNICODE -ccopt -DUNICODE mdb.c
vendor/ocaml-lmdb\mdb.c: In function 'mdb_strerror':
vendor/ocaml-lmdb\mdb.c:1809:1: warning: function may return address of local variable [-Wreturn-local-addr]
vendor/ocaml-lmdb\mdb.c:1770:7: note: declared here

Those are just warnings when compiled on Windows, the actual issue is the fact that the runner took 5 hours.

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I see. Can you disable these warnings? There's not much we plan to do for vendored code.

Are you sure this PR is not changing the behavior on windows? It really should not.

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Alizter commented Nov 19, 2025

I see. Can you disable these warnings? There's not much we plan to do for vendored code.

I've opened #12750.

Are you sure this PR is not changing the behavior on windows? It really should not.

Evidently it is changing the behaviour on Windows. I don't claim to understand it at the moment. I will leave this PR as a draft until I can get round to understanding what is happening on Windows and what I am doing wrong.

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Feel free to re-open if you intend to work on this again.

@rgrinberg rgrinberg closed this Jan 20, 2026
@Alizter Alizter reopened this Jan 29, 2026
@Alizter Alizter force-pushed the dune-exec-watch-server branch from 4c5c9f5 to 548edad Compare January 29, 2026 20:40
@Alizter Alizter marked this pull request as ready for review January 29, 2026 21:19
@Alizter Alizter requested a review from rgrinberg January 29, 2026 22:00
@Alizter Alizter force-pushed the dune-exec-watch-server branch from 78aa3dc to 1dd85c9 Compare February 2, 2026 10:51
@Alizter Alizter requested a review from rgrinberg February 2, 2026 11:18
@Alizter Alizter force-pushed the dune-exec-watch-server branch from 1dd85c9 to 5169ed2 Compare February 3, 2026 00:25
We add a way of tracking whether a job is a process group leader to the
scheduler. This allows us to avoid sending a signal to a process group
when it isn't needed.

Doing so fixes an issue with dune exec -w where rebuilds would send a
kill signal to a non-existant process group assumed to be attached to
the process we were execing.

Signed-off-by: Ali Caglayan <alizter@gmail.com>
@Alizter Alizter force-pushed the dune-exec-watch-server branch from 5169ed2 to 811f319 Compare February 5, 2026 10:01
@Alizter Alizter merged commit 2dc864c into ocaml:main Feb 6, 2026
28 checks passed
@Alizter Alizter deleted the dune-exec-watch-server branch February 6, 2026 14:24
@Alizter Alizter mentioned this pull request Feb 6, 2026
23 tasks
shonfeder added a commit to shonfeder/opam-repository that referenced this pull request Mar 2, 2026
CHANGES:

### Fixed

- `Dyn.to_string` now uses a smarter way to convert floats. This ensures that
  floats are printed with enough precision to round-trip and are valid OCaml
  lexemes. (ocaml/dune#12982, fixes ocaml/dune#12980, @Alizter)

- Fix `dune install --prefix` failing with relative paths outside the workspace
  like `../foo` (ocaml/dune#12993, fixes ocaml/dune#12241, @benodiwal)

- Delete sandboxes with broken permissions (ocaml/dune#13511, @rgrinberg)

- Fix compiling Menhir parsers that refer to sibling modules within a
  subdirectory of `(include_subdirs qualified)`. (ocaml/dune#13118, fixes ocaml/dune#11119,
  @anmonteiro)

- Fixed the dependency specification of C stubs, which could result in C
  stubs not getting rebuilt when needed (which could in turn lead to
  segmentation faults and other hard-to-track bugs).
  (ocaml/dune#13652, fixes ocaml/dune#13651, @nojb)

- Fix rpc not transferring promotion warnings to the client
  (ocaml/dune#12604, fixes ocaml/dune#12578, @ElectreAAS)

- Fix issue where `dune exec -w` was unable to kill running programs on
  rebuild. (ocaml/dune#12360, fixes ocaml/dune#12323, @Alizter)

- Resolve context and workspace binaries introduced by the respective `(env
  (binaries ..))` stanzas. (ocaml/dune#12952, fixes ocaml/dune#6220, @anmonteiro)

- Fix `diff` promotions originating from sandboxed rules. Previously, they
  would be completely ignored as the sandbox with the promoted file would be
  destroyed if the promotion fired (ocaml/dune#13520, @rgrinberg)

- Fix failure to digest installed directory targets, allowing them to be used
  as dependencies to other rules. (ocaml/dune#13045, @anmonteiro)

- Fix handling of `(select ..)` field when used with `(include_subdirs ..)`.
  `(select <path> from ..)` modules now parse `path` as a relative path
  starting from the module group root (ocaml/dune#13175, fixes ocaml/dune#4383, ocaml/dune#12450,
  @anmonteiro)

- Fix dune trying to kill processes that were already reaped due to race
  conditions (ocaml/dune#13245, @rgrinberg)

- Add `O_CLOEXEC` to all files used for stdin/stdout/stderr (ocaml/dune#13385, @rgrinberg)

- Fix `$ dune promote dir/foo` when `dir` does not exist (ocaml/dune#13493, @rgrinberg)

- Fix `(select ..)` field evaluation when a transitive library has optional
  dependencies (fixes ocaml/dune#13299, ocaml/dune#13389, @anmonteiro)

- Fix sandboxed builds of `library` stanzas that set
  `(stdlib (modules_before_stdlib ..))` (ocaml/dune#13624, @anmonteiro)

- Fixed non-build caches not following `$DUNE_CACHE_ROOT` and instead only
  relying on `$XDG_CACHE_HOME`.
  This means the normal build cache moves:
  `$DUNE_CACHE_ROOT -> $DUNE_CACHE_ROOT/db` (no changes if that variable was
  unset). Affected users can prevent a full cache invalidation by moving
  previous contents:
  `cd $DUNE_CACHE_ROOT; mkdir db; mv <contents of directory> db`.
  (ocaml/dune#11612, fixes ocaml/dune#11584, @ElectreAAS)

- `$ dune promotion list` writes output to stdout rather than stderr (ocaml/dune#13462)

- Improve handling of empty files in the `diff` action. These are now correctly
  distinguished from *empty* files. (ocaml/dune#13696, @rgrinberg)

- Pass `/dev/null` to `--diff-command` instead of non-existent files (ocaml/dune#13696,
  @rgrinberg)

- Fix failure when multiple `rocq.extraction` stanzas existing in a directory
  (ocaml/dune#13531, fixes ocaml/dune#8042, @rlepigre-skylabs-ai)

- Print `$ dune promotion show` output to stdout rather than stderr (ocaml/dune#13481,
  @rgrinberg)

- Fix deadlock in the `memo` library in the presence of dependency cycles
  (ocaml/dune#13625, @anmonteiro)

- Fix promotions that modify a directory into a file (ocaml/dune#13516, fixes ocaml/dune#4067,
  @rgrinberg)

- Fix installation of implementations of virtual libraries. This failed when
  the implementation had no private modules, but the virtual library did
  (ocaml/dune#10635, @rgrinberg)

- Respect the `(dir ..)` field on packages when setting up cram tests (ocaml/dune#13581,
  @rgrinberg)

### Added

- Add support for generating `.cms` files using oxcaml and adding `.cms` or
  `.cmt` files as compilation dependencies (ocaml/dune#13397, @spiessimon)

- Add trace events for custom actions (ocaml/dune#13265, @rgrinberg)

- Allow enabling extensions with `(using ..)` in `dune-workspace` files
  (ocaml/dune#13395, @spiessimon)

- Add sandbox extraction trace event (ocaml/dune#13544, @rgrinberg)

- Add the initial cwd to the first config event (ocaml/dune#13026, @rgrinberg)

- Dune produces trace events in `DUNE_ACTION_TRACE_DIR` if this variable
  is set. (ocaml/dune#13302, @rgrinberg)

- Add file watching events to the trace file (ocaml/dune#13038, @rgrinberg)

- Introduce the `$ dune trace cat` subcommand to view the trace file. (ocaml/dune#13055,
  @rgrinberg)

- Add diagnostic events to the trace. (ocaml/dune#13041, @rgrinberg)

- Add `DUNE_JOBS` environment variable for controlling concurrency of Dune from
  environment. The `INSIDE_DUNE` variable also now no longer controls
  concurrency (ocaml/dune#12800, @Alizter)

- Support for Rocq expected output tests (ocaml/dune#13632, @rlepigre-skylabs-ai)

- Add `rusage` information to completed processes in the trace (@rgrinberg,
  ocaml/dune#13241)

- Add process start events to the trace (ocaml/dune#13261, rgrinberg)

- Generate odoc documentation in markdown using the `@doc-markdown` alias
  (ocaml/dune#12581, @davesnx)

- Add timing information for every command executed by cram (ocaml/dune#13092,
  @rgrinberg)

- Add the workspace root to the config trace event (ocaml/dune#12922, @rgrinberg)

- Introduce the `dune-action-trace` library. This public library is to be used
  by custom actions to emit trace events while executed as part of a dune
  build. The trace events emitted through this library will be incorporated
  into dune's own trace (ocaml/dune#13348, @rgrinberg)

- Add `dune-find-dominating` to `dune.el`, a command to find the
  dominating dune file. (ocaml/dune#12696, @arvidj)

- Add a `--no-recursive` flag to `$ dune describe workspace` (ocaml/dune#13590, @rgrinberg)

- Trace events for files written directly by dune (ocaml/dune#13618, @rgrinberg)

- Allow expansion of special forms like `(:include ..)` and `%{read-lines:..}`
  in the `modules` specification for the `ocamllex`, `ocamlyacc` and `menhir`
  stanzas. (ocaml/dune#13105, ocaml/dune#13135, ocaml/dune#13157, @anmonteiro)

- Add a trace event for snapshotting the sandbox (ocaml/dune#13541, @rgrinberg)

- Add signal send and receive events to the trace (ocaml/dune#13193, @rgrinberg)

- Emit final trace event before exiting. (ocaml/dune#13018, @rgrinberg)

- `dune runtest` can now run individual test executables from `(tests)` stanzas
  and inline tests from `(library (inline_tests))` stanzas by providing their
  source files as arguments. (ocaml/dune#13064, fixes ocaml/dune#870, @Alizter)

- Add a `shell` field to the cram stanza. This field allows customizing the
  shell to be `bash` rather than `sh` (ocaml/dune#13083, @haochenx)

### Changed

- Start sandboxing the execution of tests defined with the `test` and `tests`
  stanzas (ocaml/dune#13510, ocaml/dune#13617, @rgrinberg)

- Disabled cram tests can now be run explicitly with `dune runtest disabled.t`.
  The `enabled_if` field now only controls whether a test is included in
  the `@runtest` alias. (ocaml/dune#13081, @Alizter)

- Process categories in trace events are moved to their own field in `args`
  (ocaml/dune#13024, @rgrinberg)

- Sandbox running `ocamllex` and `ocamlyacc` actions. (ocaml/dune#13098, @anmonteiro)

- Sandboxing mdx test actions is now the default starting from `0.5` (ocaml/dune#13504,
  @rgrinberg)

- Start sandboxing Melange rules by default in the `(library ..)` and
  `(melange.emit ..)` stanzas (ocaml/dune#13619, @anmonteiro)

- Introduce a promotion trace event and remove the corresponding verbose log
  message. (ocaml/dune#12949, ocaml/dune#13444, @rgrinberg)

- Change dune's trace format to emit canonical s-expressions. This improves
  performance and is better aligned with dune's usage of the format
  elsewhere. `$ dune trace cat` can also emit the trace in `--chrome-trace`
  for perfetto, or `--sexp` for regular s-expressions for interactive usage.
  (ocaml/dune#13059, @rgrinberg)

- Move all logging statements to the trace file. All log statements now contain
  structured payloads (ocaml/dune#13015, fixes ocaml/dune#12904, @rgrinberg)

- Add a target resolution event to replace the equivalent log message (ocaml/dune#12955,
  @rgrinberg)
shonfeder added a commit to shonfeder/opam-repository that referenced this pull request Mar 11, 2026
CHANGES:

### Fixed

- `Dyn.to_string` now uses a smarter way to convert floats. This ensures that
  floats are printed with enough precision to round-trip and are valid OCaml
  lexemes. (ocaml/dune#12982, fixes ocaml/dune#12980, @Alizter)

- Fix `dune install --prefix` failing with relative paths outside the workspace
  like `../foo` (ocaml/dune#12993, fixes ocaml/dune#12241, @benodiwal)

- Place the default trace file inside the build directory at the
  workspace root, rather than relative to the current directory.
  (ocaml/dune#13735, @vouillon)

- Fixed interpreting relative paths in `%{bin:..}` and `%{bin-available:..}`.
  These are now interpreted correctly, relative to the dune file they're in.
  (ocaml/dune#13712, fixes ocaml/dune#9564, @anmonteiro)

- Delete sandboxes with broken permissions (ocaml/dune#13511, @rgrinberg)

- Fix compiling Menhir parsers that refer to sibling modules within a
  subdirectory of `(include_subdirs qualified)`. (ocaml/dune#13118, fixes ocaml/dune#11119,
  @anmonteiro)

- Fixed the dependency specification of C stubs, which could result in C
  stubs not getting rebuilt when needed (which could in turn lead to
  segmentation faults and other hard-to-track bugs).
  (ocaml/dune#13652, fixes ocaml/dune#13651, @nojb)

- Fix the Dune cache on Windows by correctly handling renames onto read-only
  files. Before this change, the Dune cache would be filled but the stored
  artifacts would not generally be usable by Dune. (ocaml/dune#13713, @Nevor)

- Fix rpc not transferring promotion warnings to the client
  (ocaml/dune#12604, fixes ocaml/dune#12578, @ElectreAAS)

- Fix issue where `dune exec -w` was unable to kill running programs on
  rebuild. (ocaml/dune#12360, fixes ocaml/dune#12323, @Alizter)

- Fix package extraction on systems with tar implementations that don't
  auto-detect compression (e.g., OpenBSD). Dune now passes explicit
  decompression flags (-z for gzip, -j for bzip2) when needed, and provides
  clear error messages for unsupported formats like XZ and LZMA. (ocaml/dune#13688,
  fixes ocaml/dune#10123, @Alizter)

- Resolve context and workspace binaries introduced by the respective `(env
  (binaries ..))` stanzas. (ocaml/dune#12952, fixes ocaml/dune#6220, @anmonteiro)

- Fix `diff` promotions originating from sandboxed rules. Previously, they
  would be completely ignored as the sandbox with the promoted file would be
  destroyed if the promotion fired (ocaml/dune#13520, @rgrinberg)

- Fix failure to digest installed directory targets, allowing them to be used
  as dependencies to other rules. (ocaml/dune#13045, @anmonteiro)

- Fix handling of `(select ..)` field when used with `(include_subdirs ..)`.
  `(select <path> from ..)` modules now parse `path` as a relative path
  starting from the module group root (ocaml/dune#13175, fixes ocaml/dune#4383, ocaml/dune#12450,
  @anmonteiro)

- Fix dune trying to kill processes that were already reaped due to race
  conditions (ocaml/dune#13245, @rgrinberg)

- Add `O_CLOEXEC` to all files used for stdin/stdout/stderr (ocaml/dune#13385, @rgrinberg)

- Fix `$ dune promote dir/foo` when `dir` does not exist (ocaml/dune#13493, @rgrinberg)

- Fix `(select ..)` field evaluation when a transitive library has optional
  dependencies (fixes ocaml/dune#13299, ocaml/dune#13389, @anmonteiro)

- Fix sandboxed builds of `library` stanzas that set
  `(stdlib (modules_before_stdlib ..))` (ocaml/dune#13624, @anmonteiro)

- Dune cache: use of hard links under Windows. (ocaml/dune#13714, @Nevor)

- Fixed non-build caches not following `$DUNE_CACHE_ROOT` and instead only
  relying on `$XDG_CACHE_HOME`.
  This means the normal build cache moves:
  `$DUNE_CACHE_ROOT -> $DUNE_CACHE_ROOT/db` (no changes if that variable was
  unset). Affected users can prevent a full cache invalidation by moving
  previous contents:
  `cd $DUNE_CACHE_ROOT; mkdir db; mv <contents of directory> db`.
  (ocaml/dune#11612, fixes ocaml/dune#11584, @ElectreAAS)

- `$ dune promotion list` writes output to stdout rather than stderr (ocaml/dune#13462)

- Improve handling of empty files in the `diff` action. These are now correctly
  distinguished from *empty* files. (ocaml/dune#13696, @rgrinberg)
- Pass `/dev/null` to `--diff-command` instead of non-existent files (ocaml/dune#13696,
  @rgrinberg)

- Fix failure when multiple `rocq.extraction` stanzas existing in a directory
  (ocaml/dune#13531, fixes ocaml/dune#8042, @rlepigre-skylabs-ai)

- Print `$ dune promotion show` output to stdout rather than stderr (ocaml/dune#13481,
  @rgrinberg)

- Fix deadlock in the `memo` library in the presence of dependency cycles
  (ocaml/dune#13625, @anmonteiro)

- Fix promotions that modify a directory into a file (ocaml/dune#13516, fixes ocaml/dune#4067,
  @rgrinberg)

- Fix installation of implementations of virtual libraries. This failed when
  the implementation had no private modules, but the virtual library did
  (ocaml/dune#10635, @rgrinberg)

- Respect the `(dir ..)` field on packages when setting up cram tests (ocaml/dune#13581,
  @rgrinberg)

### Added

- Add support for generating `.cms` files using oxcaml and adding `.cms` or
  `.cmt` files as compilation dependencies (ocaml/dune#13397, @spiessimon)

- Add trace events for custom actions (ocaml/dune#13265, @rgrinberg)

- Allow enabling extensions with `(using ..)` in `dune-workspace` files
  (ocaml/dune#13395, @spiessimon)

- Add sandbox extraction trace event (ocaml/dune#13544, @rgrinberg)

- Add the initial cwd to the first config event (ocaml/dune#13026, @rgrinberg)

- Dune dune produces trace events in `DUNE_ACTION_TRACE_DIR` if this variable
  is set. (ocaml/dune#13302, @rgrinberg)

- Add file watching events to the trace file (ocaml/dune#13038, @rgrinberg)

- Introduce the `$ dune trace cat` subcommand to view the trace file. (ocaml/dune#13055,
  @rgrinberg)

- Add diagnostic events to the trace. (ocaml/dune#13041, @rgrinberg)

- Add `DUNE_JOBS` environment variable for controlling concurrency of Dune from
  environment. The `INSIDE_DUNE` variable also now no longer controls
  concurrency (ocaml/dune#12800, @Alizter)

- Support for Rocq expected output tests (ocaml/dune#13632, @rlepigre-skylabs-ai)

- Add `rusage` information to completed processes in the trace (@rgrinberg,
  ocaml/dune#13241)

- Add process start events to the trace (ocaml/dune#13261, rgrinberg)

- Generate odoc documentation in markdown using the `@doc-markdown` alias
  (ocaml/dune#12581, @davesnx)

- Add timing information for every command executed by cram (ocaml/dune#13092,
  @rgrinberg)

- Add the workspace root to the config trace event (ocaml/dune#12922, @rgrinberg)

- Introduce the `dune-action-trace` library. This public library is to be used
  by custom actions to emit trace events while executed as part of a dune
  build. The trace events emitted through this library will be incorporated
  into dune's own trace (ocaml/dune#13348, @rgrinberg)

- Add `dune-find-dominating` to `dune.el`, a command to find the
  dominating dune file. (ocaml/dune#12696, @arvidj)

- Add a `--no-recursive` flag to `$ dune describe workspace` (ocaml/dune#13590, @rgrinberg)

- Trace events for files written directly by dune (ocaml/dune#13618, @rgrinberg)

- Allow expansion of special forms like `(:include ..)` and `%{read-lines:..}`
  in the `modules` specification for the `ocamllex`, `ocamlyacc` and `menhir`
  stanzas. (ocaml/dune#13105, ocaml/dune#13135, ocaml/dune#13157, @anmonteiro)

- Add a trace event for snapshotting the asndbox (ocaml/dune#13541, @rgrinberg)

- Add signal send and receive events to the trace (ocaml/dune#13193, @rgrinberg)

- Emit final trace event before exiting. (ocaml/dune#13018, @rgrinberg)

- `dune runtest` can now run individual test executables from `(tests)` stanzas
  and inline tests from `(library (inline_tests))` stanzas by providing their
  source files as arguments. (ocaml/dune#13064, fixes ocaml/dune#870, @Alizter)

- Add a `shell` field to the cram stanza. This field allows customizing the
  shell to be `bash` rather than `sh` (ocaml/dune#13083, @haochenx)

### Changed

- Start sandboxing the execution of tests defined with the `test` and `tests`
  stanzas (ocaml/dune#13510, ocaml/dune#13617, @rgrinberg)

- Disabled cram tests can now be run explicitly with `dune runtest disabled.t`.
  The `enabled_if` field now only controls whether a test is included in
  the `@runtest` alias. (ocaml/dune#13081, @Alizter)

- Process categories in trace events are moved to their own field in `args`
  (ocaml/dune#13024, @rgrinberg)

- Sandbox running `ocamllex` and `ocamlyacc` actions. (ocaml/dune#13098, @anmonteiro)

- Sandboxing mdx test actions is now the default starting from `0.5` (ocaml/dune#13504,
  @rgrinberg)

- Start sandboxing Melange rules by default in the `(library ..)` and
  `(melange.emit ..)` stanzas (ocaml/dune#13619, @anmonteiro)

- Introduce a promotion trace event and remove the corresponding verbose log
  message. (ocaml/dune#12949, ocaml/dune#13444, @rgrinberg)

- Change dune's trace format to emit canonical s-expressions. This improves
  performance and is better aligned with dune's usage of the format
  elsewhere. `$ dune trace cat` can also emit the trace in `--chrome-trace`
  for perfetto, or `--sexp` for regular s-expressions for interactive usage.
  (ocaml/dune#13059, @rgrinberg)

- Move all logging statements to the trace file. All log statements now contain
  structured payloads (ocaml/dune#13015, fixes ocaml/dune#12904, @rgrinberg)

- Add a target resolution event to replace the equivalent log message (ocaml/dune#12955,
  @rgrinberg)
shonfeder added a commit to shonfeder/opam-repository that referenced this pull request Mar 16, 2026
CHANGES:

### Fixed

- `Dyn.to_string` now uses a smarter way to convert floats. This ensures that
  floats are printed with enough precision to round-trip and are valid OCaml
  lexemes. (ocaml/dune#12982, fixes ocaml/dune#12980, @Alizter)

- Fix `dune install --prefix` failing with relative paths outside the workspace
  like `../foo` (ocaml/dune#12993, fixes ocaml/dune#12241, @benodiwal)

- Place the default trace file inside the build directory at the
  workspace root, rather than relative to the current directory.
  (ocaml/dune#13735, @vouillon)

- Fixed interpreting relative paths in `%{bin:..}` and `%{bin-available:..}`.
  These are now interpreted correctly, relative to the dune file they're in.
  (ocaml/dune#13712, fixes ocaml/dune#9564, @anmonteiro)

- Delete sandboxes with broken permissions (ocaml/dune#13511, @rgrinberg)

- Fix compiling Menhir parsers that refer to sibling modules within a
  subdirectory of `(include_subdirs qualified)`. (ocaml/dune#13118, fixes ocaml/dune#11119,
  @anmonteiro)

- Fixed the dependency specification of C stubs, which could result in C
  stubs not getting rebuilt when needed (which could in turn lead to
  segmentation faults and other hard-to-track bugs).
  (ocaml/dune#13652, fixes ocaml/dune#13651, @nojb)

- Fix the Dune cache on Windows by correctly handling renames onto read-only
  files. Before this change, the Dune cache would be filled but the stored
  artifacts would not generally be usable by Dune. (ocaml/dune#13713, @Nevor)

- Fix rpc not transferring promotion warnings to the client
  (ocaml/dune#12604, fixes ocaml/dune#12578, @ElectreAAS)

- Fix issue where `dune exec -w` was unable to kill running programs on
  rebuild. (ocaml/dune#12360, fixes ocaml/dune#12323, @Alizter)

- Fix package extraction on systems with tar implementations that don't
  auto-detect compression (e.g., OpenBSD). Dune now passes explicit
  decompression flags (-z for gzip, -j for bzip2) when needed, and provides
  clear error messages for unsupported formats like XZ and LZMA. (ocaml/dune#13688,
  fixes ocaml/dune#10123, @Alizter)

- Resolve context and workspace binaries introduced by the respective `(env
  (binaries ..))` stanzas. (ocaml/dune#12952, fixes ocaml/dune#6220, @anmonteiro)

- Fix `diff` promotions originating from sandboxed rules. Previously, they
  would be completely ignored as the sandbox with the promoted file would be
  destroyed if the promotion fired (ocaml/dune#13520, @rgrinberg)

- Fix failure to digest installed directory targets, allowing them to be used
  as dependencies to other rules. (ocaml/dune#13045, @anmonteiro)

- Fix handling of `(select ..)` field when used with `(include_subdirs ..)`.
  `(select <path> from ..)` modules now parse `path` as a relative path
  starting from the module group root (ocaml/dune#13175, fixes ocaml/dune#4383, ocaml/dune#12450,
  @anmonteiro)

- Fix dune trying to kill processes that were already reaped due to race
  conditions (ocaml/dune#13245, @rgrinberg)

- Add `O_CLOEXEC` to all files used for stdin/stdout/stderr (ocaml/dune#13385, @rgrinberg)

- Fix `$ dune promote dir/foo` when `dir` does not exist (ocaml/dune#13493, @rgrinberg)

- Fix `(select ..)` field evaluation when a transitive library has optional
  dependencies (fixes ocaml/dune#13299, ocaml/dune#13389, @anmonteiro)

- Fix sandboxed builds of `library` stanzas that set
  `(stdlib (modules_before_stdlib ..))` (ocaml/dune#13624, @anmonteiro)

- Dune cache: use of hard links under Windows. (ocaml/dune#13714, @Nevor)

- Fixed non-build caches not following `$DUNE_CACHE_ROOT` and instead only
  relying on `$XDG_CACHE_HOME`.
  This means the normal build cache moves:
  `$DUNE_CACHE_ROOT -> $DUNE_CACHE_ROOT/db` (no changes if that variable was
  unset). Affected users can prevent a full cache invalidation by moving
  previous contents:
  `cd $DUNE_CACHE_ROOT; mkdir db; mv <contents of directory> db`.
  (ocaml/dune#11612, fixes ocaml/dune#11584, @ElectreAAS)

- `$ dune promotion list` writes output to stdout rather than stderr (ocaml/dune#13462)

- Improve handling of empty files in the `diff` action. These are now correctly
  distinguished from *empty* files. (ocaml/dune#13696, @rgrinberg)
- Pass `/dev/null` to `--diff-command` instead of non-existent files (ocaml/dune#13696,
  @rgrinberg)

- Fix failure when multiple `rocq.extraction` stanzas existing in a directory
  (ocaml/dune#13531, fixes ocaml/dune#8042, @rlepigre-skylabs-ai)

- Print `$ dune promotion show` output to stdout rather than stderr (ocaml/dune#13481,
  @rgrinberg)

- Fix deadlock in the `memo` library in the presence of dependency cycles
  (ocaml/dune#13625, @anmonteiro)

- Fix promotions that modify a directory into a file (ocaml/dune#13516, fixes ocaml/dune#4067,
  @rgrinberg)

- Fix installation of implementations of virtual libraries. This failed when
  the implementation had no private modules, but the virtual library did
  (ocaml/dune#10635, @rgrinberg)

- Respect the `(dir ..)` field on packages when setting up cram tests (ocaml/dune#13581,
  @rgrinberg)

### Added

- Add support for generating `.cms` files using oxcaml and adding `.cms` or
  `.cmt` files as compilation dependencies (ocaml/dune#13397, @spiessimon)

- Add trace events for custom actions (ocaml/dune#13265, @rgrinberg)

- Allow enabling extensions with `(using ..)` in `dune-workspace` files
  (ocaml/dune#13395, @spiessimon)

- Add sandbox extraction trace event (ocaml/dune#13544, @rgrinberg)

- Add the initial cwd to the first config event (ocaml/dune#13026, @rgrinberg)

- Dune dune produces trace events in `DUNE_ACTION_TRACE_DIR` if this variable
  is set. (ocaml/dune#13302, @rgrinberg)

- Add file watching events to the trace file (ocaml/dune#13038, @rgrinberg)

- Introduce the `$ dune trace cat` subcommand to view the trace file. (ocaml/dune#13055,
  @rgrinberg)

- Add diagnostic events to the trace. (ocaml/dune#13041, @rgrinberg)

- Add `DUNE_JOBS` environment variable for controlling concurrency of Dune from
  environment. The `INSIDE_DUNE` variable also now no longer controls
  concurrency (ocaml/dune#12800, @Alizter)

- Support for Rocq expected output tests (ocaml/dune#13632, @rlepigre-skylabs-ai)

- Add `rusage` information to completed processes in the trace (@rgrinberg,
  ocaml/dune#13241)

- Add process start events to the trace (ocaml/dune#13261, rgrinberg)

- Generate odoc documentation in markdown using the `@doc-markdown` alias
  (ocaml/dune#12581, @davesnx)

- Add timing information for every command executed by cram (ocaml/dune#13092,
  @rgrinberg)

- Add the workspace root to the config trace event (ocaml/dune#12922, @rgrinberg)

- Introduce the `dune-action-trace` library. This public library is to be used
  by custom actions to emit trace events while executed as part of a dune
  build. The trace events emitted through this library will be incorporated
  into dune's own trace (ocaml/dune#13348, @rgrinberg)

- Add `dune-find-dominating` to `dune.el`, a command to find the
  dominating dune file. (ocaml/dune#12696, @arvidj)

- Add a `--no-recursive` flag to `$ dune describe workspace` (ocaml/dune#13590, @rgrinberg)

- Trace events for files written directly by dune (ocaml/dune#13618, @rgrinberg)

- Allow expansion of special forms like `(:include ..)` and `%{read-lines:..}`
  in the `modules` specification for the `ocamllex`, `ocamlyacc` and `menhir`
  stanzas. (ocaml/dune#13105, ocaml/dune#13135, ocaml/dune#13157, @anmonteiro)

- Add a trace event for snapshotting the asndbox (ocaml/dune#13541, @rgrinberg)

- Add signal send and receive events to the trace (ocaml/dune#13193, @rgrinberg)

- Emit final trace event before exiting. (ocaml/dune#13018, @rgrinberg)

- `dune runtest` can now run individual test executables from `(tests)` stanzas
  and inline tests from `(library (inline_tests))` stanzas by providing their
  source files as arguments. (ocaml/dune#13064, fixes ocaml/dune#870, @Alizter)

- Add a `shell` field to the cram stanza. This field allows customizing the
  shell to be `bash` rather than `sh` (ocaml/dune#13083, @haochenx)

### Changed

- Start sandboxing the execution of tests defined with the `test` and `tests`
  stanzas (ocaml/dune#13510, ocaml/dune#13617, @rgrinberg)

- Disabled cram tests can now be run explicitly with `dune runtest disabled.t`.
  The `enabled_if` field now only controls whether a test is included in
  the `@runtest` alias. (ocaml/dune#13081, @Alizter)

- Process categories in trace events are moved to their own field in `args`
  (ocaml/dune#13024, @rgrinberg)

- Sandbox running `ocamllex` and `ocamlyacc` actions. (ocaml/dune#13098, @anmonteiro)

- Sandboxing mdx test actions is now the default starting from `0.5` (ocaml/dune#13504,
  @rgrinberg)

- Start sandboxing Melange rules by default in the `(library ..)` and
  `(melange.emit ..)` stanzas (ocaml/dune#13619, @anmonteiro)

- Introduce a promotion trace event and remove the corresponding verbose log
  message. (ocaml/dune#12949, ocaml/dune#13444, @rgrinberg)

- Change dune's trace format to emit canonical s-expressions. This improves
  performance and is better aligned with dune's usage of the format
  elsewhere. `$ dune trace cat` can also emit the trace in `--chrome-trace`
  for perfetto, or `--sexp` for regular s-expressions for interactive usage.
  (ocaml/dune#13059, @rgrinberg)

- Move all logging statements to the trace file. All log statements now contain
  structured payloads (ocaml/dune#13015, fixes ocaml/dune#12904, @rgrinberg)

- Add a target resolution event to replace the equivalent log message (ocaml/dune#12955,
  @rgrinberg)
shonfeder added a commit to shonfeder/opam-repository that referenced this pull request Mar 19, 2026
CHANGES:

### Fixed

- `Dyn.to_string` now uses a smarter way to convert floats. This ensures that
  floats are printed with enough precision to round-trip and are valid OCaml
  lexemes. (ocaml/dune#12982, fixes ocaml/dune#12980, @Alizter)

- Fix `dune install --prefix` failing with relative paths outside the workspace
  like `../foo` (ocaml/dune#12993, fixes ocaml/dune#12241, @benodiwal)

- Place the default trace file inside the build directory at the
  workspace root, rather than relative to the current directory.
  (ocaml/dune#13735, @vouillon)

- Fixed interpreting relative paths in `%{bin:..}` and `%{bin-available:..}`.
  These are now interpreted correctly, relative to the dune file they're in.
  (ocaml/dune#13712, fixes ocaml/dune#9564, @anmonteiro)

- Delete sandboxes with broken permissions (ocaml/dune#13511, @rgrinberg)

- Fix compiling Menhir parsers that refer to sibling modules within a
  subdirectory of `(include_subdirs qualified)`. (ocaml/dune#13118, fixes ocaml/dune#11119,
  @anmonteiro)

- Fixed the dependency specification of C stubs, which could result in C
  stubs not getting rebuilt when needed (which could in turn lead to
  segmentation faults and other hard-to-track bugs).
  (ocaml/dune#13652, fixes ocaml/dune#13651, @nojb)

- Fix the Dune cache on Windows by correctly handling renames onto read-only
  files. Before this change, the Dune cache would be filled but the stored
  artifacts would not generally be usable by Dune. (ocaml/dune#13713, @Nevor)

- Fix rpc not transferring promotion warnings to the client
  (ocaml/dune#12604, fixes ocaml/dune#12578, @ElectreAAS)

- Fix issue where `dune exec -w` was unable to kill running programs on
  rebuild. (ocaml/dune#12360, fixes ocaml/dune#12323, @Alizter)

- Resolve context and workspace binaries introduced by the respective `(env
  (binaries ..))` stanzas. (ocaml/dune#12952, fixes ocaml/dune#6220, @anmonteiro)

- Fix `diff` promotions originating from sandboxed rules. Previously, they
  would be completely ignored as the sandbox with the promoted file would be
  destroyed if the promotion fired (ocaml/dune#13520, @rgrinberg)

- Fix failure to digest installed directory targets, allowing them to be used
  as dependencies to other rules. (ocaml/dune#13045, @anmonteiro)

- Fix handling of `(select ..)` field when used with `(include_subdirs ..)`.
  `(select <path> from ..)` modules now parse `path` as a relative path
  starting from the module group root (ocaml/dune#13175, fixes ocaml/dune#4383, ocaml/dune#12450,
  @anmonteiro)

- Fix dune trying to kill processes that were already reaped due to race
  conditions (ocaml/dune#13245, @rgrinberg)

- Add `O_CLOEXEC` to all files used for stdin/stdout/stderr (ocaml/dune#13385, @rgrinberg)

- Fix `$ dune promote dir/foo` when `dir` does not exist (ocaml/dune#13493, @rgrinberg)

- Fix `(select ..)` field evaluation when a transitive library has optional
  dependencies (fixes ocaml/dune#13299, ocaml/dune#13389, @anmonteiro)

- Fix sandboxed builds of `library` stanzas that set
  `(stdlib (modules_before_stdlib ..))` (ocaml/dune#13624, @anmonteiro)

- Dune cache: use of hard links under Windows. (ocaml/dune#13714, @Nevor)

- Fixed non-build caches not following `$DUNE_CACHE_ROOT` and instead only
  relying on `$XDG_CACHE_HOME`.
  This means the normal build cache moves:
  `$DUNE_CACHE_ROOT -> $DUNE_CACHE_ROOT/db` (no changes if that variable was
  unset). Affected users can prevent a full cache invalidation by moving
  previous contents:
  `cd $DUNE_CACHE_ROOT; mkdir db; mv <contents of directory> db`.
  (ocaml/dune#11612, fixes ocaml/dune#11584, @ElectreAAS)

- `$ dune promotion list` writes output to stdout rather than stderr (ocaml/dune#13462)

- Improve handling of empty files in the `diff` action. These are now correctly
  distinguished from *empty* files. (ocaml/dune#13696, @rgrinberg)
- Pass `/dev/null` to `--diff-command` instead of non-existent files (ocaml/dune#13696,
  @rgrinberg)

- Fix failure when multiple `rocq.extraction` stanzas existing in a directory
  (ocaml/dune#13531, fixes ocaml/dune#8042, @rlepigre-skylabs-ai)

- Print `$ dune promotion show` output to stdout rather than stderr (ocaml/dune#13481,
  @rgrinberg)

- Fix deadlock in the `memo` library in the presence of dependency cycles
  (ocaml/dune#13625, @anmonteiro)

- Fix promotions that modify a directory into a file (ocaml/dune#13516, fixes ocaml/dune#4067,
  @rgrinberg)

- Fix installation of implementations of virtual libraries. This failed when
  the implementation had no private modules, but the virtual library did
  (ocaml/dune#10635, @rgrinberg)

- Respect the `(dir ..)` field on packages when setting up cram tests (ocaml/dune#13581,
  @rgrinberg)

### Added

- Add support for generating `.cms` files using oxcaml and adding `.cms` or
  `.cmt` files as compilation dependencies (ocaml/dune#13397, @spiessimon)

- Add trace events for custom actions (ocaml/dune#13265, @rgrinberg)

- Allow enabling extensions with `(using ..)` in `dune-workspace` files
  (ocaml/dune#13395, @spiessimon)

- Add sandbox extraction trace event (ocaml/dune#13544, @rgrinberg)

- Add the initial cwd to the first config event (ocaml/dune#13026, @rgrinberg)

- Dune dune produces trace events in `DUNE_ACTION_TRACE_DIR` if this variable
  is set. (ocaml/dune#13302, @rgrinberg)

- Add file watching events to the trace file (ocaml/dune#13038, @rgrinberg)

- Introduce the `$ dune trace cat` subcommand to view the trace file. (ocaml/dune#13055,
  @rgrinberg)

- Add diagnostic events to the trace. (ocaml/dune#13041, @rgrinberg)

- Add `DUNE_JOBS` environment variable for controlling concurrency of Dune from
  environment. The `INSIDE_DUNE` variable also now no longer controls
  concurrency (ocaml/dune#12800, @Alizter)

- Support for Rocq expected output tests (ocaml/dune#13632, @rlepigre-skylabs-ai)

- Add `rusage` information to completed processes in the trace (@rgrinberg,
  ocaml/dune#13241)

- Add process start events to the trace (ocaml/dune#13261, rgrinberg)

- Generate odoc documentation in markdown using the `@doc-markdown` alias
  (ocaml/dune#12581, @davesnx)

- Add timing information for every command executed by cram (ocaml/dune#13092,
  @rgrinberg)

- Add the workspace root to the config trace event (ocaml/dune#12922, @rgrinberg)

- Introduce the `dune-action-trace` library. This public library is to be used
  by custom actions to emit trace events while executed as part of a dune
  build. The trace events emitted through this library will be incorporated
  into dune's own trace (ocaml/dune#13348, @rgrinberg)

- Add `dune-find-dominating` to `dune.el`, a command to find the
  dominating dune file. (ocaml/dune#12696, @arvidj)

- Add a `--no-recursive` flag to `$ dune describe workspace` (ocaml/dune#13590, @rgrinberg)

- Trace events for files written directly by dune (ocaml/dune#13618, @rgrinberg)

- Allow expansion of special forms like `(:include ..)` and `%{read-lines:..}`
  in the `modules` specification for the `ocamllex`, `ocamlyacc` and `menhir`
  stanzas. (ocaml/dune#13105, ocaml/dune#13135, ocaml/dune#13157, @anmonteiro)

- Add a trace event for snapshotting the asndbox (ocaml/dune#13541, @rgrinberg)

- Add signal send and receive events to the trace (ocaml/dune#13193, @rgrinberg)

- Emit final trace event before exiting. (ocaml/dune#13018, @rgrinberg)

- `dune runtest` can now run individual test executables from `(tests)` stanzas
  and inline tests from `(library (inline_tests))` stanzas by providing their
  source files as arguments. (ocaml/dune#13064, fixes ocaml/dune#870, @Alizter)

- Add a `shell` field to the cram stanza. This field allows customizing the
  shell to be `bash` rather than `sh` (ocaml/dune#13083, @haochenx)

### Changed

- Start sandboxing the execution of tests defined with the `test` and `tests`
  stanzas (ocaml/dune#13510, ocaml/dune#13617, @rgrinberg)

- Disabled cram tests can now be run explicitly with `dune runtest disabled.t`.
  The `enabled_if` field now only controls whether a test is included in
  the `@runtest` alias. (ocaml/dune#13081, @Alizter)

- Process categories in trace events are moved to their own field in `args`
  (ocaml/dune#13024, @rgrinberg)

- Sandbox running `ocamllex` and `ocamlyacc` actions. (ocaml/dune#13098, @anmonteiro)

- Sandboxing mdx test actions is now the default starting from `0.5` (ocaml/dune#13504,
  @rgrinberg)

- Start sandboxing Melange rules by default in the `(library ..)` and
  `(melange.emit ..)` stanzas (ocaml/dune#13619, @anmonteiro)

- Introduce a promotion trace event and remove the corresponding verbose log
  message. (ocaml/dune#12949, ocaml/dune#13444, @rgrinberg)

- Change dune's trace format to emit canonical s-expressions. This improves
  performance and is better aligned with dune's usage of the format
  elsewhere. `$ dune trace cat` can also emit the trace in `--chrome-trace`
  for perfetto, or `--sexp` for regular s-expressions for interactive usage.
  (ocaml/dune#13059, @rgrinberg)

- Move all logging statements to the trace file. All log statements now contain
  structured payloads (ocaml/dune#13015, fixes ocaml/dune#12904, @rgrinberg)

- Add a target resolution event to replace the equivalent log message (ocaml/dune#12955,
  @rgrinberg)
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dune exec --watch broken for long-running processes

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