Stop changing the default warning set of the compiler by nojb · Pull Request #12766 · ocaml/dune

nojb · 2025-11-21T17:02:11Z

This PR follows the discussion in #8645 (comment) and in many other places.

It makes so that starting in version 3.21 of the Dune language, Dune no longer changes the warning set of the compiler. Instead, a variable of "recommended" warnings %{dune-warnings} is made available for interested users (see test).

Signed-off-by: Nicolás Ojeda Bär <n.oje.bar@gmail.com>

rgrinberg · 2025-11-21T17:56:22Z

src/dune_rules/expander.ml

+           let+ scope = scope in
+           let dune_version = Dune_project.dune_version (Scope.project scope) in
+           let profile = Context.profile context in
+           Value.L.strings (Ocaml_flags.dune_warnings ~dune_version ~profile)))


I think this value should not be dependant on the profile. The users can already insert this under dev in the env stanza.

Good point. Fixed in 68caf05

Signed-off-by: Nicolás Ojeda Bär <n.oje.bar@gmail.com>

Alizter · 2025-11-21T19:34:23Z

Needs a changes entry and an update to the documentation.

Signed-off-by: Nicolás Ojeda Bär <n.oje.bar@gmail.com>

nojb · 2025-11-21T19:40:00Z

Needs a changes entry and an update to the documentation.

Changes entry done. Which documentation should I look at?

Alizter · 2025-11-21T20:02:06Z

Here are a few places I could find:

faq.rst has some discussion about warnings.
variables.rst could use an update together with introduced version
overview.rst has mention of "strict" warnings that might need updating

Signed-off-by: Nicolás Ojeda Bär <n.oje.bar@gmail.com>

nojb · 2025-11-21T20:45:31Z

Here are a few places I could find:

Thanks for the pointers. I updated what I could. The doc about the new variable renders as thus:

nojb · 2025-11-21T20:46:33Z

Some of the NIX tests need investigating (maybe the failures are normal and the tests just need updating), but I don't have a NIX environment at hand...

Alizter · 2025-11-21T22:12:50Z

You should be able to run the tests without nix using the opam setup. The test failures should mostly be the same.

Signed-off-by: Nicolás Ojeda Bär <n.oje.bar@gmail.com>

nojb · 2025-11-22T08:15:50Z

You should be able to run the tests without nix using the opam setup. The test failures should mostly be the same.

Thanks. The test failures revealed a small bug, which is fixed in 9ac4ca7

Signed-off-by: Nicolás Ojeda Bär <n.oje.bar@gmail.com>

rgrinberg · 2025-11-23T10:46:50Z

doc/changes/changed/12766.md

@@ -0,0 +1,4 @@
+- Starting with version 3.21 of the Dune language, Dune no longer changes the


Since dune itself is already using 3.21, you should use %{dune-warnings} in our root dune file.

Good catch. Fixed in 5c4861b

Signed-off-by: Nicolás Ojeda Bär <n.oje.bar@gmail.com>

maiste · 2025-11-23T18:30:40Z

I'm not involved actively in the dune release management process anymore but I would advice to delay this for after the 3.21 release. There is a bigger delay than usual for the release. From my experience, it means there will already be a lot of risk of breaking packages. I would keep this for a 3.22 version, which would contain this specific change. It would allow the dune team to make sure it doesn't break any package, give time to user to adapt (by announcing it in advance), and provide the functionalities from the 3.21 without waiting.

If it may help with this change and make it smoother 🤗

Thanks @nojb for tackling this subject 😁

Alizter · 2025-11-24T10:01:10Z

Since this doesn't affect the release profile, I am less worried about breaking packages. If it does end up being problematic for whatever reason we can always revert, however I think that is unlikely.

doc/changes/changed/12766.md

Signed-off-by: Nicolás Ojeda Bär <n.oje.bar@gmail.com>

nojb · 2025-11-24T10:43:37Z

@rgrinberg Are you happy with the present state of the PR?

src/dune_rules/ocaml_flags.ml

aguluman · 2025-11-28T10:15:16Z

Starting with version 3.21 of the Dune language, Dune no longer changes the
default set of compiler warnings. For users that would like to keep the old
behaviour, the variable %{dune-warnings} can be used in the (flags) field.

Hello, a rookie here.
If I don't attach %{dune-warnings} will I stop receiving [unused-var] and other warnings as errors in my dune build flow?
Trying to understand, apologies if you have to repeat yourself another time.

nojb · 2025-11-28T10:33:41Z

If I don't attach %{dune-warnings} will I stop receiving [unused-var] and other warnings as errors in my dune build flow?

Yes, if you have (lang dune 3.21) (or later) in your dune-project.

Alizter · 2025-11-28T10:38:13Z

And just to be clear, if you are using (lang dune 3.20) or lower, even with a newer dune you won't see any difference.

aguluman · 2025-11-28T10:43:46Z

And just to be clear, if you are using (lang dune 3.20) or lower, even with a newer dune you won't see any difference.

Thanks for this information.
I currently have 3.20.2

How about what Nicolas said regarding using a dune version of 3.21 and needing %{dune-warnings}
I will still be getting [unused-*] as default?

@ElectreAAS

CHANGES: ### Fixed - Fix `include_subdirs qualified` incorrectly picking the furthest module instead of the closest when resolving module name ambiguities. (ocaml/dune#12587, @ElectreAAS and @Alizter) - Fix: include the module alias in the transitive dependency closure with `(include_subdirs qualified)`. (ocaml/dune#12299, @anmonteiro) - Improve error messages for invalid version formats containing non-ASCII characters. Previously, non-ASCII characters in version strings (e.g., `(lang dune è)` or `(using menhir π3.14)`) would fail with a generic "Invalid file" error. Now they display a clear message: "Invalid atom: contains non-ASCII character(s). Atoms must only contain ASCII characters." The fix is implemented at the lexer level, providing consistent error handling across all s-expression parsing. (ocaml/dune#12844, fixes ocaml/dune#12836, @benodiwal) - Pass private modules with -H when this is available (ocaml/dune#12666, @rgrinberg) - Allow multiple modules in `(modules_flags ...)`, in `coq.theory` (ocaml/dune#12733, @rlepigre) - Improve error message for invalid version formats in both `(lang dune ...)` and `(using extension ...)` declarations. Changes "Atom of the form NNN.NNN expected" to "Invalid version. Version must be two numbers separated by a dot." (ocaml/dune#12833, @benodiwal) - Fix crash when running `dune build @check` on a library with virtual modules. (ocaml/dune#12644, fixes ocaml/dune#12636, @Alizter) - Provide a more informative error message when `(pkg enabled)` is put in `dune-project` instead of `dune-workspace`. (ocaml/dune#12802, fixes ocaml/dune#12801, @benodiwal) - Improve error message when invalid version strings are used in `dune-project` files. Non-ASCII characters and malformed versions now show a helpful hint with an example of the correct format. (ocaml/dune#12794, fixes ocaml/dune#12751, @benodiwal) - Stop hiding the `root_module` from the include path (ocaml/dune#12239, @rgrinberg) - Allow `$ dune init` to work on absolute paths (ocaml/dune#12601, fixes ocaml/dune#7806, @rgrinberg) - `(include_subdirs qualified)`: Add missing alias dependency to module group. (ocaml/dune#12530, @anmonteiro) - Add Melange compilation to the `@all` alias in libraries (ocaml/dune#12628, @anmonteiro) - Fix greedy version location in lang declarations. Previously, error locations for invalid lang versions would span multiple bytes for multi-byte UTF-8 characters, causing carets to appear misaligned and seemingly include the closing parenthesis. Now, error locations for ASCII strings show the full length (e.g., "Ali" shows `^^^`), while non-ASCII strings show only the first byte (e.g., "è" shows `^`) to avoid multi-byte character display issues. (ocaml/dune#12869, fixes ocaml/dune#12806, @benodiwal) - melange support: don't emit empty JavaScript modules for generated module aliases. (ocaml/dune#12464, @anmonteiro) ### Added - (Experimental): Introduce the `library_parameter` stanza. It allows users to declare a parameter when using the OxCaml compiler. (ocaml/dune#11963, implements ocaml/dune#12084, @maiste) - Added the ability to scroll horizontally in TUI. (ocaml/dune#12386, @Alizter) - Feature: Include shell command that was executed when a cram test has occurred in the error message (ocaml/dune#12307, @rgrinberg) - support expanding variables in `(promote (into ..))` (ocaml/dune#12832, fixes ocaml/dune#12742, @anmonteiro) - Add support for `%{cmt:...}` and `%{cmti:...}` variables to reference compiled annotation files (.cmt and .cmti) containing typed abstract syntax trees with location and type information. (ocaml/dune#12634, grants ocaml/dune#12633, @Alizter) - Add `$ dune describe tests` to describe the tests in the workspace (@Gromototo, ocaml/dune#12545, fixes ocaml/dune#12030) - Add `argv`, the process environment, and the dune version to the config event in the trace (ocaml/dune#12909, @rgrinberg) - Allow `dune runtest` to properly run while a watch mode server is running. (ocaml/dune#12473, grants ocaml/dune#8114, @gridbugs and @ElectreAAS) - Use copy-on-write (COW) when copying files on filesystems that support it (Btrfs, ZFS, XFS, etc), under Linux. (ocaml/dune#12074, fixes ocaml/dune#12071, @nojb) - Add support for Tangled ATproto-based code repositories (ocaml/dune#12197, @avsm) - Add support for instantiating OxCaml parameterised libraries. (ocaml/dune#12561, @art-w) - Add a `(conflict_markers error|ignore)` option to the cram stanza. When `(conflict_markers error)` is set, the cram test will fail in the presence of conflict markers. Git, diff3 and jujutsu conflict markers are detected. (ocaml/dune#12538, ocaml/dune#12617, ocaml/dune#12655, fixes ocaml/dune#12512, @rgrinberg, @Alizter) - Introduce a `%{ppx:lib1+..+libn}` stanza to make it possible to refer to ppx executables built by dune. This is useful for writing tests (ocaml/dune#12711, @rgrinberg) - Introduce a `(dir ..)` field on packages defined in the `dune-project`. This field allows to associate a directory with a particular package. This makes dune automatically filter out all stanzas in this directory and its descendants with `--only-packages`. All users are recommended to switch to using this field. (ocaml/dune#12614, fixes ocaml/dune#3255, @rgrinberg) - Add support for `DUNE_ROOT` environment variable, similar to the existing `--root` CLI parameter. (fixes ocaml/dune#12399 @sir4ur0n) - Introduce an `unused-libs` alias to detect unused libraries. (ocaml/dune#12623, fixes ocaml/dune#650, @rgrinberg) - Add `--files` flag to `dune describe opam-files` to print only the names of the opam files line by line. (ocaml/dune#9793, @reynir and @Alizter) - `dune exec` now accepts absolute paths inside the workspace. (ocaml/dune#12094, @Alizter) - Add `coqdoc_header` and `coqdoc_footer` fields to the `coq` field of the `env` stanza, and to the `coq.theory` stanza, allowing to configure a custom header or footer respectively in the HTML output of `coqdoc`. (ocaml/dune#11131, @rlepigre) - Allow `dune fmt` to properly run while a watch mode server is running. Note that the `--preview` flag is not supported in this mode. (ocaml/dune#12064, @ElectreAAS) - Support for generating `_CoqProject` files for `coq.theory` stanzas. (ocaml/dune#11752, @rlepigre) - Added `(files)` stanza, similar to `(dirs)` to control which files are visible to Dune on a per-directory basis. (ocaml/dune#12879, @nojb) - Add support for %{ocaml-config:ox} (ocaml/dune#12236, @jonludlam) - Introduce `dune promotion show` command to display the contents of corrected files that are ready for promotion. This allows users to preview changes before running `dune promote`. The command accepts file arguments to show specific files, or displays all promotable files when called without arguments. (ocaml/dune#12669, fixes ocaml/dune#3883, @MixiMaxiMouse) - New `(lang rocq)` build mode for Rocq 9.0 and later. This new mode is very similar to the existing `(lang coq)`, except that it doesn't need the `coq*` compatibility wrappers. As of today `(lang rocq)` doesn't support yet composed builds with Rocq itself, this will be added later. `(lang coq)` is deprecated, development is frozen, and will be removed at some point in the future. (ocaml/dune#12035, @ejgallego, @Lysxia, fixes ocaml/dune#11572) ### Changed - Don't run `ocamldep` to compute false dependencies on the `root_module` (ocaml/dune#12227, @rgrinberg) - `dune format-dune-file` now uses the syntax version of the Dune project that contains the file being formatted (if any) instead of using the latest version available, which remains the default if there is no Dune project in scope. (ocaml/dune#11865, @nojb) - Persistent DB and process events have been slightly modified. Persistent DB events have more concise names and job events always include full information. (ocaml/dune#12867, @rgrinberg) - Removed the `--trace-extended` flag. Its functionality is always enabled when tracing is active (ocaml/dune#12908, @rgrinberg) - The `test/dune` file generated by `dune init proj` now depends on the project library. (ocaml/dune#12791, @shonfeder) - Starting with version 3.21 of the Dune language, Dune no longer changes the default set of compiler warnings. For users that would like to keep the old behaviour, the variable `%{dune-warnings}` can be used in an `(env)` stanza in a top-level Dune file: `(env (dev (flags :standard %{dune-warnings})))`. (ocaml/dune#12766, @nojb) - Fix: stop generating `cmt` files for cinaps binaries (ocaml/dune#12530, @rgrinberg)

@ElectreAAS

CHANGES: ### Fixed - Fix `include_subdirs qualified` incorrectly picking the furthest module instead of the closest when resolving module name ambiguities. (ocaml/dune#12587, @ElectreAAS and @Alizter) - Fix: include the module alias in the transitive dependency closure with `(include_subdirs qualified)`. (ocaml/dune#12299, @anmonteiro) - Improve error messages for invalid version formats containing non-ASCII characters. Previously, non-ASCII characters in version strings (e.g., `(lang dune è)` or `(using menhir π3.14)`) would fail with a generic "Invalid file" error. Now they display a clear message: "Invalid atom: contains non-ASCII character(s). Atoms must only contain ASCII characters." The fix is implemented at the lexer level, providing consistent error handling across all s-expression parsing. (ocaml/dune#12844, fixes ocaml/dune#12836, @benodiwal) - Pass private modules with -H when this is available (ocaml/dune#12666, @rgrinberg) - Allow multiple modules in `(modules_flags ...)`, in `coq.theory` (ocaml/dune#12733, @rlepigre) - Improve error message for invalid version formats in both `(lang dune ...)` and `(using extension ...)` declarations. Changes "Atom of the form NNN.NNN expected" to "Invalid version. Version must be two numbers separated by a dot." (ocaml/dune#12833, @benodiwal) - Fix crash when running `dune build @check` on a library with virtual modules. (ocaml/dune#12644, fixes ocaml/dune#12636, @Alizter) - Provide a more informative error message when `(pkg enabled)` is put in `dune-project` instead of `dune-workspace`. (ocaml/dune#12802, fixes ocaml/dune#12801, @benodiwal) - Improve error message when invalid version strings are used in `dune-project` files. Non-ASCII characters and malformed versions now show a helpful hint with an example of the correct format. (ocaml/dune#12794, fixes ocaml/dune#12751, @benodiwal) - Stop hiding the `root_module` from the include path (ocaml/dune#12239, @rgrinberg) - Allow `$ dune init` to work on absolute paths (ocaml/dune#12601, fixes ocaml/dune#7806, @rgrinberg) - `(include_subdirs qualified)`: Add missing alias dependency to module group. (ocaml/dune#12530, @anmonteiro) - Add Melange compilation to the `@all` alias in libraries (ocaml/dune#12628, @anmonteiro) - Fix greedy version location in lang declarations. Previously, error locations for invalid lang versions would span multiple bytes for multi-byte UTF-8 characters, causing carets to appear misaligned and seemingly include the closing parenthesis. Now, error locations for ASCII strings show the full length (e.g., "Ali" shows `^^^`), while non-ASCII strings show only the first byte (e.g., "è" shows `^`) to avoid multi-byte character display issues. (ocaml/dune#12869, fixes ocaml/dune#12806, @benodiwal) - melange support: don't emit empty JavaScript modules for generated module aliases. (ocaml/dune#12464, @anmonteiro) ### Added - (Experimental): Introduce the `library_parameter` stanza. It allows users to declare a parameter when using the OxCaml compiler. (ocaml/dune#11963, implements ocaml/dune#12084, @maiste) - Added the ability to scroll horizontally in TUI. (ocaml/dune#12386, @Alizter) - Feature: Include shell command that was executed when a cram test has occurred in the error message (ocaml/dune#12307, @rgrinberg) - support expanding variables in `(promote (into ..))` (ocaml/dune#12832, fixes ocaml/dune#12742, @anmonteiro) - Add support for `%{cmt:...}` and `%{cmti:...}` variables to reference compiled annotation files (.cmt and .cmti) containing typed abstract syntax trees with location and type information. (ocaml/dune#12634, grants ocaml/dune#12633, @Alizter) - Add `$ dune describe tests` to describe the tests in the workspace (@Gromototo, ocaml/dune#12545, fixes ocaml/dune#12030) - Add `argv`, the process environment, and the dune version to the config event in the trace (ocaml/dune#12909, @rgrinberg) - Allow `dune runtest` to properly run while a watch mode server is running. (ocaml/dune#12473, grants ocaml/dune#8114, @gridbugs and @ElectreAAS) - Use copy-on-write (COW) when copying files on filesystems that support it (Btrfs, ZFS, XFS, etc), under Linux. (ocaml/dune#12074, fixes ocaml/dune#12071, @nojb) - Add support for Tangled ATproto-based code repositories (ocaml/dune#12197, @avsm) - Add support for instantiating OxCaml parameterised libraries. (ocaml/dune#12561, @art-w) - Add a `(conflict_markers error|ignore)` option to the cram stanza. When `(conflict_markers error)` is set, the cram test will fail in the presence of conflict markers. Git, diff3 and jujutsu conflict markers are detected. (ocaml/dune#12538, ocaml/dune#12617, ocaml/dune#12655, fixes ocaml/dune#12512, @rgrinberg, @Alizter) - Introduce a `%{ppx:lib1+..+libn}` stanza to make it possible to refer to ppx executables built by dune. This is useful for writing tests (ocaml/dune#12711, @rgrinberg) - Introduce a `(dir ..)` field on packages defined in the `dune-project`. This field allows to associate a directory with a particular package. This makes dune automatically filter out all stanzas in this directory and its descendants with `--only-packages`. All users are recommended to switch to using this field. (ocaml/dune#12614, fixes ocaml/dune#3255, @rgrinberg) - Add support for `DUNE_ROOT` environment variable, similar to the existing `--root` CLI parameter. (fixes ocaml/dune#12399 @sir4ur0n) - Introduce an `unused-libs` alias to detect unused libraries. (ocaml/dune#12623, fixes ocaml/dune#650, @rgrinberg) - Add `--files` flag to `dune describe opam-files` to print only the names of the opam files line by line. (ocaml/dune#9793, @reynir and @Alizter) - `dune exec` now accepts absolute paths inside the workspace. (ocaml/dune#12094, @Alizter) - Add `coqdoc_header` and `coqdoc_footer` fields to the `coq` field of the `env` stanza, and to the `coq.theory` stanza, allowing to configure a custom header or footer respectively in the HTML output of `coqdoc`. (ocaml/dune#11131, @rlepigre) - Allow `dune fmt` to properly run while a watch mode server is running. Note that the `--preview` flag is not supported in this mode. (ocaml/dune#12064, @ElectreAAS) - Support for generating `_CoqProject` files for `coq.theory` stanzas. (ocaml/dune#11752, @rlepigre) - Added `(files)` stanza, similar to `(dirs)` to control which files are visible to Dune on a per-directory basis. (ocaml/dune#12879, @nojb) - Add support for %{ocaml-config:ox} (ocaml/dune#12236, @jonludlam) - Introduce `dune promotion show` command to display the contents of corrected files that are ready for promotion. This allows users to preview changes before running `dune promote`. The command accepts file arguments to show specific files, or displays all promotable files when called without arguments. (ocaml/dune#12669, fixes ocaml/dune#3883, @MixiMaxiMouse) - New `(lang rocq)` build mode for Rocq 9.0 and later. This new mode is very similar to the existing `(lang coq)`, except that it doesn't need the `coq*` compatibility wrappers. As of today `(lang rocq)` doesn't support yet composed builds with Rocq itself, this will be added later. `(lang coq)` is deprecated, development is frozen, and will be removed at some point in the future. (ocaml/dune#12035, @ejgallego, @Lysxia, fixes ocaml/dune#11572) ### Changed - Don't run `ocamldep` to compute false dependencies on the `root_module` (ocaml/dune#12227, @rgrinberg) - `dune format-dune-file` now uses the syntax version of the Dune project that contains the file being formatted (if any) instead of using the latest version available, which remains the default if there is no Dune project in scope. (ocaml/dune#11865, @nojb) - Persistent DB and process events have been slightly modified. Persistent DB events have more concise names and job events always include full information. (ocaml/dune#12867, @rgrinberg) - Removed the `--trace-extended` flag. Its functionality is always enabled when tracing is active (ocaml/dune#12908, @rgrinberg) - The `test/dune` file generated by `dune init proj` now depends on the project library. (ocaml/dune#12791, @shonfeder) - Starting with version 3.21 of the Dune language, Dune no longer changes the default set of compiler warnings. For users that would like to keep the old behaviour, the variable `%{dune-warnings}` can be used in an `(env)` stanza in a top-level Dune file: `(env (dev (flags :standard %{dune-warnings})))`. (ocaml/dune#12766, @nojb) - Fix: stop generating `cmt` files for cinaps binaries (ocaml/dune#12530, @rgrinberg)

@ElectreAAS

CHANGES: ### Fixed - Fix `include_subdirs qualified` incorrectly picking the furthest module instead of the closest when resolving module name ambiguities. (ocaml/dune#12587, @ElectreAAS and @Alizter) - Fix: include the module alias in the transitive dependency closure with `(include_subdirs qualified)`. (ocaml/dune#12299, @anmonteiro) - Improve error messages for invalid version formats containing non-ASCII characters. Previously, non-ASCII characters in version strings (e.g., `(lang dune è)` or `(using menhir π3.14)`) would fail with a generic "Invalid file" error. Now they display a clear message: "Invalid atom: contains non-ASCII character(s). Atoms must only contain ASCII characters." The fix is implemented at the lexer level, providing consistent error handling across all s-expression parsing. (ocaml/dune#12844, fixes ocaml/dune#12836, @benodiwal) - Pass private modules with -H when this is available (ocaml/dune#12666, @rgrinberg) - Allow multiple modules in `(modules_flags ...)`, in `coq.theory` (ocaml/dune#12733, @rlepigre) - Improve error message for invalid version formats in both `(lang dune ...)` and `(using extension ...)` declarations. Changes "Atom of the form NNN.NNN expected" to "Invalid version. Version must be two numbers separated by a dot." (ocaml/dune#12833, @benodiwal) - Fix crash when running `dune build @check` on a library with virtual modules. (ocaml/dune#12644, fixes ocaml/dune#12636, @Alizter) - Provide a more informative error message when `(pkg enabled)` is put in `dune-project` instead of `dune-workspace`. (ocaml/dune#12802, fixes ocaml/dune#12801, @benodiwal) - Improve error message when invalid version strings are used in `dune-project` files. Non-ASCII characters and malformed versions now show a helpful hint with an example of the correct format. (ocaml/dune#12794, fixes ocaml/dune#12751, @benodiwal) - Stop hiding the `root_module` from the include path (ocaml/dune#12239, @rgrinberg) - Allow `$ dune init` to work on absolute paths (ocaml/dune#12601, fixes ocaml/dune#7806, @rgrinberg) - `(include_subdirs qualified)`: Add missing alias dependency to module group. (ocaml/dune#12530, @anmonteiro) - Add Melange compilation to the `@all` alias in libraries (ocaml/dune#12628, @anmonteiro) - Fix greedy version location in lang declarations. Previously, error locations for invalid lang versions would span multiple bytes for multi-byte UTF-8 characters, causing carets to appear misaligned and seemingly include the closing parenthesis. Now, error locations for ASCII strings show the full length (e.g., "Ali" shows `^^^`), while non-ASCII strings show only the first byte (e.g., "è" shows `^`) to avoid multi-byte character display issues. (ocaml/dune#12869, fixes ocaml/dune#12806, @benodiwal) - melange support: don't emit empty JavaScript modules for generated module aliases. (ocaml/dune#12464, @anmonteiro) ### Added - (Experimental): Introduce the `library_parameter` stanza. It allows users to declare a parameter when using the OxCaml compiler. (ocaml/dune#11963, implements ocaml/dune#12084, @maiste) - Added the ability to scroll horizontally in TUI. (ocaml/dune#12386, @Alizter) - Feature: Include shell command that was executed when a cram test has occurred in the error message (ocaml/dune#12307, @rgrinberg) - support expanding variables in `(promote (into ..))` (ocaml/dune#12832, fixes ocaml/dune#12742, @anmonteiro) - Add support for `%{cmt:...}` and `%{cmti:...}` variables to reference compiled annotation files (.cmt and .cmti) containing typed abstract syntax trees with location and type information. (ocaml/dune#12634, grants ocaml/dune#12633, @Alizter) - Add `$ dune describe tests` to describe the tests in the workspace (@Gromototo, ocaml/dune#12545, fixes ocaml/dune#12030) - Add `argv`, the process environment, and the dune version to the config event in the trace (ocaml/dune#12909, @rgrinberg) - Allow `dune runtest` to properly run while a watch mode server is running. (ocaml/dune#12473, grants ocaml/dune#8114, @gridbugs and @ElectreAAS) - Use copy-on-write (COW) when copying files on filesystems that support it (Btrfs, ZFS, XFS, etc), under Linux. (ocaml/dune#12074, fixes ocaml/dune#12071, @nojb) - Add support for Tangled ATproto-based code repositories (ocaml/dune#12197, @avsm) - Add support for instantiating OxCaml parameterised libraries. (ocaml/dune#12561, @art-w) - Add a `(conflict_markers error|ignore)` option to the cram stanza. When `(conflict_markers error)` is set, the cram test will fail in the presence of conflict markers. Git, diff3 and jujutsu conflict markers are detected. (ocaml/dune#12538, ocaml/dune#12617, ocaml/dune#12655, fixes ocaml/dune#12512, @rgrinberg, @Alizter) - Introduce a `%{ppx:lib1+..+libn}` stanza to make it possible to refer to ppx executables built by dune. This is useful for writing tests (ocaml/dune#12711, @rgrinberg) - Introduce a `(dir ..)` field on packages defined in the `dune-project`. This field allows to associate a directory with a particular package. This makes dune automatically filter out all stanzas in this directory and its descendants with `--only-packages`. All users are recommended to switch to using this field. (ocaml/dune#12614, fixes ocaml/dune#3255, @rgrinberg) - Add support for `DUNE_ROOT` environment variable, similar to the existing `--root` CLI parameter. (fixes ocaml/dune#12399 @sir4ur0n) - Introduce an `unused-libs` alias to detect unused libraries. (ocaml/dune#12623, fixes ocaml/dune#650, @rgrinberg) - Add `--files` flag to `dune describe opam-files` to print only the names of the opam files line by line. (ocaml/dune#9793, @reynir and @Alizter) - `dune exec` now accepts absolute paths inside the workspace. (ocaml/dune#12094, @Alizter) - Add `coqdoc_header` and `coqdoc_footer` fields to the `coq` field of the `env` stanza, and to the `coq.theory` stanza, allowing to configure a custom header or footer respectively in the HTML output of `coqdoc`. (ocaml/dune#11131, @rlepigre) - Allow `dune fmt` to properly run while a watch mode server is running. Note that the `--preview` flag is not supported in this mode. (ocaml/dune#12064, @ElectreAAS) - Support for generating `_CoqProject` files for `coq.theory` stanzas. (ocaml/dune#11752, @rlepigre) - Added `(files)` stanza, similar to `(dirs)` to control which files are visible to Dune on a per-directory basis. (ocaml/dune#12879, @nojb) - Add support for %{ocaml-config:ox} (ocaml/dune#12236, @jonludlam) - Introduce `dune promotion show` command to display the contents of corrected files that are ready for promotion. This allows users to preview changes before running `dune promote`. The command accepts file arguments to show specific files, or displays all promotable files when called without arguments. (ocaml/dune#12669, fixes ocaml/dune#3883, @MixiMaxiMouse) - New `(lang rocq)` build mode for Rocq 9.0 and later. This new mode is very similar to the existing `(lang coq)`, except that it doesn't need the `coq*` compatibility wrappers. As of today `(lang rocq)` doesn't support yet composed builds with Rocq itself, this will be added later. `(lang coq)` is deprecated, development is frozen, and will be removed at some point in the future. (ocaml/dune#12035, @ejgallego, @Lysxia, fixes ocaml/dune#11572) ### Changed - Don't run `ocamldep` to compute false dependencies on the `root_module` (ocaml/dune#12227, @rgrinberg) - `dune format-dune-file` now uses the syntax version of the Dune project that contains the file being formatted (if any) instead of using the latest version available, which remains the default if there is no Dune project in scope. (ocaml/dune#11865, @nojb) - Persistent DB and process events have been slightly modified. Persistent DB events have more concise names and job events always include full information. (ocaml/dune#12867, @rgrinberg) - Removed the `--trace-extended` flag. Its functionality is always enabled when tracing is active (ocaml/dune#12908, @rgrinberg) - The `test/dune` file generated by `dune init proj` now depends on the project library. (ocaml/dune#12791, @shonfeder) - Starting with version 3.21 of the Dune language, Dune no longer changes the default set of compiler warnings. For users that would like to keep the old behaviour, the variable `%{dune-warnings}` can be used in an `(env)` stanza in a top-level Dune file: `(env (dev (flags :standard %{dune-warnings})))`. (ocaml/dune#12766, @nojb) - Fix: stop generating `cmt` files for cinaps binaries (ocaml/dune#12530, @rgrinberg)

@Alizter

CHANGES: ### Fixed - Fix build issues on NetBSD and OpenBSD via update of vendored ocaml-lmdb (@Alizter, ocaml/dune#13074) - Fix `melange.emit` not respecting the package mask via `-p <PKG>` (ocaml/dune#13522, @anmonteiro) ### Changed - Stop starting RPC server with `$ dune promote` (ocaml/dune#13428, @rgrinberg) @ElectreAAS and @Alizter) - Fix: include the module alias in the transitive dependency closure with `(include_subdirs qualified)`. (ocaml/dune#12299, @anmonteiro) - Improve error messages for invalid version formats containing non-ASCII characters. Previously, non-ASCII characters in version strings (e.g., `(lang dune è)` or `(using menhir π3.14)`) would fail with a generic "Invalid file" error. Now they display a clear message: "Invalid atom: contains non-ASCII character(s). Atoms must only contain ASCII characters." The fix is implemented at the lexer level, providing consistent error handling across all s-expression parsing. (ocaml/dune#12844, fixes ocaml/dune#12836, @benodiwal) - Pass private modules with -H when this is available (ocaml/dune#12666, @rgrinberg) - Allow multiple modules in `(modules_flags ...)`, in `coq.theory` (ocaml/dune#12733, @rlepigre) - Improve error message for invalid version formats in both `(lang dune ...)` and `(using extension ...)` declarations. Changes "Atom of the form NNN.NNN expected" to "Invalid version. Version must be two numbers separated by a dot." (ocaml/dune#12833, @benodiwal) - Fix crash when running `dune build @check` on a library with virtual modules. (ocaml/dune#12644, fixes ocaml/dune#12636, @Alizter) - Provide a more informative error message when `(pkg enabled)` is put in `dune-project` instead of `dune-workspace`. (ocaml/dune#12802, fixes ocaml/dune#12801, @benodiwal) - Improve error message when invalid version strings are used in `dune-project` files. Non-ASCII characters and malformed versions now show a helpful hint with an example of the correct format. (ocaml/dune#12794, fixes ocaml/dune#12751, @benodiwal) - Stop hiding the `root_module` from the include path (ocaml/dune#12239, @rgrinberg) - Allow `$ dune init` to work on absolute paths (ocaml/dune#12601, fixes ocaml/dune#7806, @rgrinberg) - `(include_subdirs qualified)`: Add missing alias dependency to module group. (ocaml/dune#12530, @anmonteiro) - Add Melange compilation to the `@all` alias in libraries (ocaml/dune#12628, @anmonteiro) - Fix greedy version location in lang declarations. Previously, error locations for invalid lang versions would span multiple bytes for multi-byte UTF-8 characters, causing carets to appear misaligned and seemingly include the closing parenthesis. Now, error locations for ASCII strings show the full length (e.g., "Ali" shows `^^^`), while non-ASCII strings show only the first byte (e.g., "è" shows `^`) to avoid multi-byte character display issues. (ocaml/dune#12869, fixes ocaml/dune#12806, @benodiwal) - melange support: don't emit empty JavaScript modules for generated module aliases. (ocaml/dune#12464, @anmonteiro) ### Added - (Experimental): Introduce the `library_parameter` stanza. It allows users to declare a parameter when using the OxCaml compiler. (ocaml/dune#11963, implements ocaml/dune#12084, @maiste) - Added the ability to scroll horizontally in TUI. (ocaml/dune#12386, @Alizter) - Feature: Include shell command that was executed when a cram test has occurred in the error message (ocaml/dune#12307, @rgrinberg) - support expanding variables in `(promote (into ..))` (ocaml/dune#12832, fixes ocaml/dune#12742, @anmonteiro) - Add support for `%{cmt:...}` and `%{cmti:...}` variables to reference compiled annotation files (.cmt and .cmti) containing typed abstract syntax trees with location and type information. (ocaml/dune#12634, grants ocaml/dune#12633, @Alizter) - Add `$ dune describe tests` to describe the tests in the workspace (@Gromototo, ocaml/dune#12545, fixes ocaml/dune#12030) - Add `argv`, the process environment, and the dune version to the config event in the trace (ocaml/dune#12909, @rgrinberg) - Allow `dune runtest` to properly run while a watch mode server is running. (ocaml/dune#12473, grants ocaml/dune#8114, @gridbugs and @ElectreAAS) - Use copy-on-write (COW) when copying files on filesystems that support it (Btrfs, ZFS, XFS, etc), under Linux. (ocaml/dune#12074, fixes ocaml/dune#12071, @nojb) - Add support for Tangled ATproto-based code repositories (ocaml/dune#12197, @avsm) - Add support for instantiating OxCaml parameterised libraries. (ocaml/dune#12561, @art-w) - Add a `(conflict_markers error|ignore)` option to the cram stanza. When `(conflict_markers error)` is set, the cram test will fail in the presence of conflict markers. Git, diff3 and jujutsu conflict markers are detected. (ocaml/dune#12538, ocaml/dune#12617, ocaml/dune#12655, fixes ocaml/dune#12512, @rgrinberg, @Alizter) - Introduce a `%{ppx:lib1+..+libn}` stanza to make it possible to refer to ppx executables built by dune. This is useful for writing tests (ocaml/dune#12711, @rgrinberg) - Introduce a `(dir ..)` field on packages defined in the `dune-project`. This field allows to associate a directory with a particular package. This makes dune automatically filter out all stanzas in this directory and its descendants with `--only-packages`. All users are recommended to switch to using this field. (ocaml/dune#12614, fixes ocaml/dune#3255, @rgrinberg) - Add support for `DUNE_ROOT` environment variable, similar to the existing `--root` CLI parameter. (fixes ocaml/dune#12399 @sir4ur0n) - Introduce an `unused-libs` alias to detect unused libraries. (ocaml/dune#12623, fixes ocaml/dune#650, @rgrinberg) - Add `--files` flag to `dune describe opam-files` to print only the names of the opam files line by line. (ocaml/dune#9793, @reynir and @Alizter) - `dune exec` now accepts absolute paths inside the workspace. (ocaml/dune#12094, @Alizter) - Add `coqdoc_header` and `coqdoc_footer` fields to the `coq` field of the `env` stanza, and to the `coq.theory` stanza, allowing to configure a custom header or footer respectively in the HTML output of `coqdoc`. (ocaml/dune#11131, @rlepigre) - Allow `dune fmt` to properly run while a watch mode server is running. Note that the `--preview` flag is not supported in this mode. (ocaml/dune#12064, @ElectreAAS) - Support for generating `_CoqProject` files for `coq.theory` stanzas. (ocaml/dune#11752, @rlepigre) - Added `(files)` stanza, similar to `(dirs)` to control which files are visible to Dune on a per-directory basis. (ocaml/dune#12879, @nojb) - Add support for %{ocaml-config:ox} (ocaml/dune#12236, @jonludlam) - Introduce `dune promotion show` command to display the contents of corrected files that are ready for promotion. This allows users to preview changes before running `dune promote`. The command accepts file arguments to show specific files, or displays all promotable files when called without arguments. (ocaml/dune#12669, fixes ocaml/dune#3883, @MixiMaxiMouse) - New `(lang rocq)` build mode for Rocq 9.0 and later. This new mode is very similar to the existing `(lang coq)`, except that it doesn't need the `coq*` compatibility wrappers. As of today `(lang rocq)` doesn't support yet composed builds with Rocq itself, this will be added later. `(lang coq)` is deprecated, development is frozen, and will be removed at some point in the future. (ocaml/dune#12035, @ejgallego, @Lysxia, fixes ocaml/dune#11572) ### Changed - Don't run `ocamldep` to compute false dependencies on the `root_module` (ocaml/dune#12227, @rgrinberg) - `dune format-dune-file` now uses the syntax version of the Dune project that contains the file being formatted (if any) instead of using the latest version available, which remains the default if there is no Dune project in scope. (ocaml/dune#11865, @nojb) - Persistent DB and process events have been slightly modified. Persistent DB events have more concise names and job events always include full information. (ocaml/dune#12867, @rgrinberg) - Removed the `--trace-extended` flag. Its functionality is always enabled when tracing is active (ocaml/dune#12908, @rgrinberg) - The `test/dune` file generated by `dune init proj` now depends on the project library. (ocaml/dune#12791, @shonfeder) - Starting with version 3.21 of the Dune language, Dune no longer changes the default set of compiler warnings. For users that would like to keep the old behaviour, the variable `%{dune-warnings}` can be used in an `(env)` stanza in a top-level Dune file: `(env (dev (flags :standard %{dune-warnings})))`. (ocaml/dune#12766, @nojb) - Fix: stop generating `cmt` files for cinaps binaries (ocaml/dune#12530, @rgrinberg)

Stop changing the default OCaml warnings

39a6c57

Signed-off-by: Nicolás Ojeda Bär <n.oje.bar@gmail.com>

nojb mentioned this pull request Nov 21, 2025

warning 9 enabled by default in dev mode #8645

Closed

Add test

7fbe8fb

Signed-off-by: Nicolás Ojeda Bär <n.oje.bar@gmail.com>

nojb force-pushed the dune_warnings branch from 2f26445 to 7fbe8fb Compare November 21, 2025 17:08

rgrinberg reviewed Nov 21, 2025

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%{dune-warnings} should not depend on the profile

68caf05

Signed-off-by: Nicolás Ojeda Bär <n.oje.bar@gmail.com>

Changes

1556ac6

Signed-off-by: Nicolás Ojeda Bär <n.oje.bar@gmail.com>

nojb force-pushed the dune_warnings branch from 574744a to 1556ac6 Compare November 21, 2025 19:37

Doc

f5ea470

Signed-off-by: Nicolás Ojeda Bär <n.oje.bar@gmail.com>

Fix

9ac4ca7

Signed-off-by: Nicolás Ojeda Bär <n.oje.bar@gmail.com>

nojb added 3 commits November 22, 2025 09:31

Merge branch 'main' into dune_warnings

2d097d6

Wording

746953e

Signed-off-by: Nicolás Ojeda Bär <n.oje.bar@gmail.com>

Merge branch 'main' into dune_warnings

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rgrinberg reviewed Nov 23, 2025

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nojb added 2 commits November 23, 2025 11:51

Use %{dune-warnings} in Dune itself

5c4861b

Signed-off-by: Nicolás Ojeda Bär <n.oje.bar@gmail.com>

Merge branch 'main' into dune_warnings

c9a450e

Alizter reviewed Nov 24, 2025

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nojb added 2 commits November 24, 2025 11:16

Changes

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Signed-off-by: Nicolás Ojeda Bär <n.oje.bar@gmail.com>

Merge branch 'main' into dune_warnings

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Alizter approved these changes Nov 24, 2025

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Alizter requested a review from rgrinberg November 24, 2025 11:05

Alizter reviewed Nov 24, 2025

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Alizter reviewed Nov 24, 2025

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nojb added 2 commits November 24, 2025 16:59

Merge branch 'main' into dune_warnings

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Merge branch 'main' into dune_warnings

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rgrinberg approved these changes Nov 25, 2025

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Merge branch 'main' into dune_warnings

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nojb merged commit 7d4d0fc into ocaml:main Nov 26, 2025
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nojb deleted the dune_warnings branch November 26, 2025 07:52

shonfeder mentioned this pull request Dec 11, 2025

[new release] dune (17 packages) (3.21.0~alpha3) ocaml/opam-repository#29070

Closed

shonfeder mentioned this pull request Dec 15, 2025

[new release] dune (17 packages) (3.21.0~alpha4) ocaml/opam-repository#29096

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shonfeder mentioned this pull request Jan 5, 2026

[new release] dune (17 packages) (3.21.0~alpha5) ocaml/opam-repository#29189

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shonfeder mentioned this pull request Jan 12, 2026

[new release] dune (17 packages) (3.21.0) ocaml/opam-repository#29216

Merged

shonfeder mentioned this pull request Feb 11, 2026

[new release] dune (17 packages) (3.21.1~alpha0) ocaml/opam-repository#29373

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		@@ -0,0 +1,4 @@
		- Starting with version 3.21 of the Dune language, Dune no longer changes the

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