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@rgrinberg rgrinberg commented Oct 25, 2025

Introduce an alias unused-libs that will error out if it detects any used libraries.

  • add a way to add intentionally unused libraries
  • add some docs
  • add a test demonstrate that some unused dependency cannot be detected
  • changes

In the future, we could consider adding an alias per library or executable stanza if anybody wants such granularity.

Fixes #650

@rgrinberg rgrinberg marked this pull request as ready for review October 25, 2025 03:03
Alizter
Alizter previously approved these changes Oct 27, 2025
@rgrinberg rgrinberg force-pushed the ocamlobjinfo-multi-files branch from ff31b91 to 5ea10af Compare October 27, 2025 15:33
@rgrinberg rgrinberg changed the title refactor: ocamlobjinfo with multiple files feature: add an unused-libs alias Oct 27, 2025
@rgrinberg rgrinberg requested a review from nojb October 27, 2025 15:34
@rgrinberg rgrinberg marked this pull request as draft October 27, 2025 15:34
@rgrinberg rgrinberg force-pushed the ocamlobjinfo-multi-files branch 5 times, most recently from 49e8456 to 848e13e Compare October 27, 2025 21:20
@rgrinberg rgrinberg force-pushed the ocamlobjinfo-multi-files branch from 848e13e to 9f7438c Compare November 6, 2025 23:01
@rgrinberg rgrinberg marked this pull request as ready for review November 6, 2025 23:01
@rgrinberg rgrinberg force-pushed the ocamlobjinfo-multi-files branch from 9f7438c to 00742fd Compare November 6, 2025 23:02
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@nojb this is ready now

@rgrinberg rgrinberg force-pushed the ocamlobjinfo-multi-files branch from 00742fd to 1f46798 Compare November 9, 2025 21:28
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ping @nojb. We're preparing a release and I think users would be pleased to see this feature finally arrive.

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LGTM

Sorry for the lag, been really busy, as usual.

Just to confirm: if one links an executable with -linkall then none of the libraries will be "unused", right?

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Sorry, a quick follow-up to the previous review (see question below). Also, I think the allow_unused_libraries field is not documented.

@rgrinberg rgrinberg force-pushed the ocamlobjinfo-multi-files branch from 1f46798 to 6f15c31 Compare November 15, 2025 18:54
Signed-off-by: Rudi Grinberg <[email protected]>
Introduce an alias to detect unused libraries in libraries and
executable stanzas.

This stanza relies on information extracted using ocamlobjinfo to detect
which modules are actually used

Signed-off-by: Rudi Grinberg <[email protected]>

feature: allow_unused_libraries

Signed-off-by: Rudi Grinberg <[email protected]>
@rgrinberg rgrinberg force-pushed the ocamlobjinfo-multi-files branch from 6f15c31 to 5f76e87 Compare November 15, 2025 22:25
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Sorry, a quick follow-up to the previous review (see question below). Also, I think the allow_unused_libraries field is not documented.

Been disabled now. It will need a bit more refactoring and thought to support without unnecessary duplication.

@rgrinberg rgrinberg merged commit 8329919 into ocaml:main Nov 15, 2025
10 of 11 checks passed
shonfeder added a commit to shonfeder/opam-repository that referenced this pull request Dec 15, 2025
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)
shonfeder added a commit to shonfeder/opam-repository that referenced this pull request Jan 5, 2026
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)
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Dune should warn about dependencies on unused libraries

3 participants