test: regression baseline for (modules ...) cmi glob over-invalidation

test/blackbox-tests/test-cases/per-module-lib-deps/unwrapped-explicit-modules.t

@@ -0,0 +1,114 @@
+Regression baseline for the cctx-wide `.cmi` glob over an unwrapped
+library whose module set is declared explicitly via `(modules ...)`.
+Today, editing one sibling module's `.mli` invalidates every
+sibling's compile rule — even siblings that don't reference it.
+
+Matches the shape raised in #14492's review feedback. The explicit
+`(modules ...)` clause routes through a different parse path from
+the implicit form covered by `lib-to-lib-unwrapped.t`.
+
+  $ make_dune_project 3.24
+
+`foo` is `(wrapped false)` with two modules `a`, `b`, declared
+explicitly. Each module's `.ml` carries `extra` from the start so
+the `.mli` edits below are interface-only.
+
+  $ mkdir foo
+  $ cat > foo/dune <<EOF
+  > (library
+  >  (name foo)
+  >  (wrapped false)
+  >  (modules a b))
+  > EOF
+  $ cat > foo/a.ml <<EOF
+  > let v = 1
+  > let extra = "x"
+  > EOF
+  $ cat > foo/a.mli <<EOF
+  > val v : int
+  > EOF
+  $ cat > foo/b.ml <<EOF
+  > let v = 2
+  > let extra = "y"
+  > EOF
+  $ cat > foo/b.mli <<EOF
+  > val v : int
+  > EOF
+
+`consumer` is `(wrapped false)` and depends on `foo`. `uses_a`
+references `A` only; `uses_b` references `B` only.
+
+  $ mkdir consumer
+  $ cat > consumer/dune <<EOF
+  > (library
+  >  (name consumer)
+  >  (wrapped false)
+  >  (libraries foo))
+  > EOF
+  $ cat > consumer/uses_a.ml <<EOF
+  > let _ = A.v
+  > EOF
+  $ cat > consumer/uses_b.ml <<EOF
+  > let _ = B.v
+  > EOF
+
+  $ dune build @check
+
+Each consumer compile rule carries a wide `.cmi` glob over `foo`'s
+objdir; no specific cmi from `foo` appears as a file dep. The wide
+glob is the structural cause of the sibling over-rebuilds asserted
+below.
+
+  $ dune rules --root . --format=json --deps '%{cmo:consumer/uses_a}' > deps_a.json
+  $ dune rules --root . --format=json --deps '%{cmo:consumer/uses_b}' > deps_b.json
+  $ jq -r 'include "dune"; .[] | depsGlobs
+  >   | select(.dir | endswith("foo/.foo.objs/byte"))
+  >   | .dir + " " + .predicate' < deps_a.json
+  _build/default/foo/.foo.objs/byte *.cmi
+  $ jq -r 'include "dune"; .[] | depsGlobs
+  >   | select(.dir | endswith("foo/.foo.objs/byte"))
+  >   | .dir + " " + .predicate' < deps_b.json
+  _build/default/foo/.foo.objs/byte *.cmi
+  $ jq -r 'include "dune"; .[] | depsFilePaths
+  >   | select(endswith("foo/.foo.objs/byte/a.cmi"))' < deps_a.json
+  $ jq -r 'include "dune"; .[] | depsFilePaths
+  >   | select(endswith("foo/.foo.objs/byte/b.cmi"))' < deps_b.json
+
+Case 1: edit `A`'s interface to expose `extra`. `uses_b` references
+only `B`, but the cctx-wide `.cmi` glob over `foo`'s objdir includes
+`A.cmi`, so today `uses_b.cm*` rebuilds anyway.
+
+  $ cat > foo/a.mli <<EOF
+  > val v : int
+  > val extra : string
+  > EOF
+  $ dune build @check
+  $ dune trace cat | jq -s 'include "dune"; [.[] | targetsMatching("uses_b.cm")]'
+  [
+    {
+      "target_files": [
+        "_build/default/consumer/.consumer.objs/byte/uses_b.cmi",
+        "_build/default/consumer/.consumer.objs/byte/uses_b.cmo",
+        "_build/default/consumer/.consumer.objs/byte/uses_b.cmt"
+      ]
+    }
+  ]
+
+Case 2: edit `B`'s interface to expose `extra`. Symmetric — today
+`uses_a.cm*` rebuilds anyway.
+
+  $ cat > foo/b.mli <<EOF
+  > val v : int
+  > val extra : string
+  > EOF
+  $ dune build @check
+  $ dune trace cat | jq -s 'include "dune"; [.[] | targetsMatching("uses_a.cm")]'
+  [
+    {
+      "target_files": [
+        "_build/default/consumer/.consumer.objs/byte/uses_a.cmi",
+        "_build/default/consumer/.consumer.objs/byte/uses_a.cmo",
+        "_build/default/consumer/.consumer.objs/byte/uses_a.cmt"
+      ]
+    }
+  ]