Expose 'ocamlc -config' parameter 'ox' #12236

jonludlam · 2025-08-20T16:27:43Z

This is to allow for easy access to whether a compiler is an oxcaml one or not.

I initially exposed this as the parameter 'ocaml-config:oxcaml' but then decided to stick precisely with what the output of ocamlc -config gives. This makes it hard to change the name of that value, so it's worth confirming this constraint is OK with the oxcaml devs.

test/blackbox-tests/test-cases/ocaml-config-ox.t/run.t

rgrinberg · 2025-08-20T17:30:48Z

For reference, do you have the corresponding PR that introduced this change?

Alizter · 2025-08-20T17:33:48Z

We already have the %{oxcaml_supported} variable. Or is this different?

jonludlam · 2025-08-20T20:56:22Z

For reference, do you have the corresponding PR that introduced this change?

oxcaml/oxcaml@86911a1

jonludlam · 2025-08-20T21:00:51Z

We already have the %{oxcaml_supported} variable. Or is this different?

This seems a bit more robust to me than matching the version number to 'jst' or 'ox', and fitted in nicely with the other ocaml-config variables. I think there's a reasonable argument to expose the rest of the values provided by ocamlc -config, many of which seem to me to be a bit like feature flags (e.g. 'parameterised-modules', 'stack-allocation', etc). This could help as these features get upstreamed, maybe?

(I should probably also mention that the oxcaml_supported change predates the change that added the flag to ocamlc -config)

rgrinberg · 2025-08-20T21:08:32Z

This seems a bit more robust to me than matching the version number to 'jst' or 'ox', and fitted in nicely with the other ocaml-config variables

I agree. Why don't we change the implementation of oxcaml_supported then as well?

I think there's a reasonable argument to expose the rest of the values provided by ocamlc -config, many of which seem to me to be a bit like feature flags (e.g. 'parameterised-modules', 'stack-allocation', etc). This could help as these features get upstreamed, maybe?

That would be welcome as well.

maiste

I agree that the goal was to have this to replace the +ox lookup functions. We should update these functions to also check for the ocaml_config. This way we would make oxcaml_supported use it.

maiste · 2025-08-21T16:09:46Z

test/blackbox-tests/test-cases/ocaml-config-ox.t/dune

My suggestion would be for the test cases to be in the test-cases/oxcaml repository as it is related to it.

It is related, true, but these test cases are only run when running on oxcaml, yes? I'd quite like to make sure it doesn't cause a failure if it's run under mainline ocaml too.

I've added a test in the oxcaml dir too, which actually checks the result.

rgrinberg · 2025-08-26T20:58:46Z

@jonludlam do you mind adding a CHANGES entry?

test/blackbox-tests/test-cases/oxcaml/ocaml-config-ox-true.t

Signed-off-by: Jon Ludlam <[email protected]>

Signed-off-by: Ali Caglayan <[email protected]>

Signed-off-by: Jon Ludlam <[email protected]>

@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 reviewed Aug 20, 2025

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rgrinberg approved these changes Aug 20, 2025

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Alizter added the oxcaml Related to the support to OxCaml functionnalities label Aug 20, 2025

Alizter requested a review from maiste August 21, 2025 15:17

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Alizter mentioned this pull request Sep 4, 2025

Check for parameterised libraries from the compiler config #12393

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test/blackbox-tests/test-cases/oxcaml/ocaml-config-ox-true.t Show resolved Hide resolved

jonludlam and others added 5 commits September 4, 2025 14:07

Expose the ocamlc -config parameter "ox"

e90808c

Signed-off-by: Jon Ludlam <[email protected]>

Clarify variable vars in ocaml_config.ml

9c48ecd

Signed-off-by: Jon Ludlam <[email protected]>

Turn the %{ocaml-config:ox} test into one file, and add a +ve test case

ad9da1a

Signed-off-by: Jon Ludlam <[email protected]>

Add changes

ff6a390

Signed-off-by: Jon Ludlam <[email protected]>

Update test/blackbox-tests/test-cases/oxcaml/ocaml-config-ox-true.t

a95648b

Signed-off-by: Ali Caglayan <[email protected]>

Alizter force-pushed the ocaml-config-ox branch from e9f6425 to a95648b Compare September 4, 2025 11:07

Update test/blackbox-tests/test-cases/ocaml-config-ox.t

0c7e27f

Signed-off-by: Jon Ludlam <[email protected]>

Alizter merged commit 459092e into ocaml:main Sep 4, 2025
26 checks passed

jonludlam deleted the ocaml-config-ox branch September 4, 2025 15:44

shonfeder mentioned this pull request Dec 11, 2025

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

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

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