scaffold: thread Lib_index, has_virtual_impl, pps_runtime_libs through cctx by robinbb · Pull Request #14514 · ocaml/dune

robinbb · 2026-05-13T18:22:33Z

Layer 2 of 9 of #14492.

Threads lib_index, has_virtual_impl, and pps_runtime_libs through Compilation_context.t. Adds build_lib_index (constructs the Lib_index from the cctx's libs, indexing on post-pp modules for non-staged-ppx local libs). Wires ~pps_runtime_libs at all nine Compilation_context.create call sites: computed from Lib.Compile.pps + Lib.ppx_runtime_deps at Lib_rules, Exe_rules, Cinaps, and Toplevel; Resolve.Memo.return [] at Ppx_driver, Utop, Mdx, Inline_tests, and Melange_rules. Exposes Dep_graph.dir / mem for layer 4's can_filter guard. Adds Modules.as_singleton.

pps_runtime_libs is a required parameter of Compilation_context.create — no implicit default — so a new caller cannot silently drop ppx runtime libs from the dep set under narrowing (per @Alizter's review feedback). Fields are populated but never consumed by L2's own logic; consumers arrive in layer 4.

Stack: rebases on main (L1 merged in #14513). Next: #14515.

Part of #14492. Related to #4572.

Copilot

Pull request overview

This PR scaffolds dependency-filtering data through Compilation_context.t for later layers of the inter-library per-module dependency work.

Changes:

Adds lib_index, has_virtual_impl, and pps_runtime_libs to compilation contexts.
Builds a Lib_file_deps.Lib_index from direct/hidden library dependencies.
Exposes small helper APIs on Modules and Dep_graph.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
`src/dune_rules/modules.mli`	Exposes `Modules.as_singleton`.
`src/dune_rules/modules.ml`	Implements singleton detection for module sets.
`src/dune_rules/lib_rules.ml`	Passes PPX runtime libraries into library compilation contexts.
`src/dune_rules/exe_rules.ml`	Passes PPX runtime libraries into executable compilation contexts.
`src/dune_rules/dep_graph.mli`	Exposes dependency graph directory and membership helpers.
`src/dune_rules/dep_graph.ml`	Implements dependency graph directory and membership helpers.
`src/dune_rules/compilation_context.mli`	Adds accessors for lib index, virtual implementation status, and PPX runtime libraries.
`src/dune_rules/compilation_context.ml`	Stores new context fields and constructs the library dependency index.

Copilot

Pull request overview

Copilot reviewed 10 out of 10 changed files in this pull request and generated 1 comment.

#14513) Layer 1 of 9 stacked PRs reconstructing #14492 in reviewable layers. Adds the dataflow infrastructure subsequent layers consume — `Lib_file_deps.Lib_index`, `deps_of_entries`, `deps_of_entry_modules`, `Ocamldep.read_immediate_deps_words` (top-level cache keyed on (source path, ml_kind)), and `Ocamldep.read_immediate_deps_raw_of`. No consumer yet. Stack: this PR → main. Next: #14514. Part of #14492. Related to #4572.

Copilot

Pull request overview

Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.

The optional argument with default [Resolve.Memo.return []] hid the silent-wrongness Alizter flagged on #14514: a new caller that forgets to pass [~pps_runtime_libs] would silently drop ppx runtime libs from the must-glob set under narrowing. Make the parameter required. The five sites without a meaningful pps_runtime_libs to compute (ppx_driver, utop, mdx, inline_tests, melange) now pass [Resolve.Memo.return []] explicitly, documenting the absence at the call site rather than at the API. Melange compile rules bypass narrowing today (`can_filter = false` in module_compilation.ml), so the explicit empty preserves prior behaviour. utop's pps surface (collected from in-scope libraries) could in principle carry runtime libs; treat this as a separate follow-up rather than papering over via API. Signed-off-by: Robin Bate Boerop <me@robinbb.com>

Copilot

Pull request overview

Copilot reviewed 17 out of 17 changed files in this pull request and generated no new comments.

The optional argument with default [Resolve.Memo.return []] hid the silent-wrongness Alizter flagged on #14514: a new caller that forgets to pass [~pps_runtime_libs] would silently drop ppx runtime libs from the must-glob set under narrowing. Make the parameter required. The five sites without a meaningful pps_runtime_libs to compute (ppx_driver, utop, mdx, inline_tests, melange) now pass [Resolve.Memo.return []] explicitly, documenting the absence at the call site rather than at the API. Melange compile rules bypass narrowing today (`can_filter = false` in module_compilation.ml), so the explicit empty preserves prior behaviour. utop's pps surface (collected from in-scope libraries) could in principle carry runtime libs; treat this as a separate follow-up rather than papering over via API. Signed-off-by: Robin Bate Boerop <me@robinbb.com>

…h cctx Pure-additive scaffolding for #4572's per-module inter-library filter. Fields are populated but no consumer reads them yet; the per-module filter (which is the only caller) lands in a follow-up. [Compilation_context]: - [build_lib_index]: builds a [Lib_file_deps.Lib_index.t] from the cctx's direct + hidden libs. Each entry carries [Some Module.t] for unwrapped locals (tight-eligible) and [None] otherwise (wrapped locals / externals). Local libs whose source is preprocessed by a non-staged ppx are indexed on the post-pp module so the cross-lib walker reads ocamldep on the same source the dep lib's compile pipeline produces. - Three new fields on [t]: [lib_index] (Memo.Lazy.t computing the index), [has_virtual_impl] (Memo.Lazy.t flag — true iff any dep lib implements a virtual lib), and [pps_runtime_libs] (closure of ppx_runtime_libraries introduced by [pps] in this stanza, threaded through [create]). - Accessors for each. [for_module_generated_at_link_time] populates [lib_index] with a [Code_error.raise] sentinel — the per-module filter's [can_filter] guard prevents reaching it from synthesised link-time cctxs. [Lib_rules] / [Exe_rules]: compute [pps_runtime_libs] from the stanza's [compile_info] and thread it through [Compilation_context.create]. [Dep_graph]: expose [dir] and [mem]; the cross-lib walker's [can_filter] guard uses these to detect synthesised dummy graphs. [Modules]: add [as_singleton] returning [Some m] iff the module set is a single user-written module. Used by [build_lib_index] to detect the single-module-no-deps short-circuit case. Signed-off-by: Robin Bate Boerop <me@robinbb.com>

The cinaps and toplevel `Compilation_context.create` call sites omit the new `?pps_runtime_libs` field, leaving it at the default `Resolve.Memo.return []`. Under the per-module narrowing introduced later in the stack, this silently drops ppx runtime libs from `must_glob_libs`, producing missing `.cmi` globs in the stanzas' compile rules. Compute and pass it via the same `Lib.Compile.pps` + `Lib.ppx_runtime_deps` pattern used in `exe_rules.ml` and `lib_rules.ml`. Melange bypasses narrowing (`can_filter = false`) so it keeps the optional default and is unaffected today. Signed-off-by: Robin Bate Boerop <me@robinbb.com>

The optional argument with default [Resolve.Memo.return []] hid the silent-wrongness Alizter flagged on #14514: a new caller that forgets to pass [~pps_runtime_libs] would silently drop ppx runtime libs from the must-glob set under narrowing. Make the parameter required. The five sites without a meaningful pps_runtime_libs to compute (ppx_driver, utop, mdx, inline_tests, melange) now pass [Resolve.Memo.return []] explicitly, documenting the absence at the call site rather than at the API. Melange compile rules bypass narrowing today (`can_filter = false` in module_compilation.ml), so the explicit empty preserves prior behaviour. utop's pps surface (collected from in-scope libraries) could in principle carry runtime libs; treat this as a separate follow-up rather than papering over via API. Signed-off-by: Robin Bate Boerop <me@robinbb.com>

Alizter

There is no noticeable change that I've seen from reviewing this. The nature of being an interim PR means I've had to relax scrutiny especially for redundant or copy-pasted code. The implicit assumption is that this can be cleaned up in a future PR once the main features they are leading towards are merged.

robinbb self-assigned this May 13, 2026

This was referenced May 13, 2026

infra: Lib_index, deps_of_entries, deps_of_entry_modules, raw ocamldep #14513

Merged

refactor: route lib file deps through [lib_deps_for_module] #14515

Merged

Filter inter-library dependencies per module #14492

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robinbb force-pushed the robinbb-14492-l1-lib-index-infra branch 6 times, most recently from a3ab9c8 to 55c7882 Compare May 13, 2026 23:30

robinbb force-pushed the robinbb-14492-l2-cctx-fields branch from c804917 to d37e419 Compare May 13, 2026 23:30

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robinbb force-pushed the robinbb-14492-l2-cctx-fields branch 3 times, most recently from 7459ded to 22fcd5f Compare May 14, 2026 00:28

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robinbb assigned Alizter May 14, 2026

robinbb marked this pull request as ready for review May 14, 2026 00:51

Base automatically changed from robinbb-14492-l1-lib-index-infra to main May 14, 2026 11:16

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robinbb force-pushed the robinbb-14492-test-stack-integration branch from 686951f to 8a00b1d Compare May 19, 2026 23:48

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scaffold: thread Lib_index, has_virtual_impl, pps_runtime_libs through cctx#14514

scaffold: thread Lib_index, has_virtual_impl, pps_runtime_libs through cctx#14514
Alizter merged 3 commits into
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robinbb-14492-l2-cctx-fields

robinbb commented May 13, 2026 •

edited

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robinbb commented May 13, 2026 •

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