test: reproduce @ocaml-index failing with package management

test/blackbox-tests/test-cases/ocaml-index/gh10985.t

@@ -0,0 +1,59 @@
+This test attempts to build the ocaml index while depending on a library
+installed through a lock file.
+
+We set up a library that will be installed as part of the package:
+
+  $ mkdir external_sources
+  $ cat >external_sources/dune-project <<EOF
+  > (lang dune 3.11)
+  > (package (name mypkg))
+  > EOF
+  $ cat >external_sources/dune <<EOF
+  > (library
+  >  (public_name mypkg.lib)
+  >  (name test_lib))
+  > EOF
+  $ cat >external_sources/test_lib.ml <<EOF
+  > let x = ()
+  > EOF
+
+We put the actual build in a separate directory, so we don't have to ignore
+the package directory in the dune file:
+  $ mkdir actual
+  $ cd actual
+
+Now we set up a lock file with this package and then attempt to use it:
+
+  $ cat >dune-project <<EOF
+  > (lang dune 3.11)
+  > EOF
+
+  $ mkdir dune.lock
+  $ cat >dune.lock/lock.dune <<EOF
+  > (lang package 0.1)
+  > EOF
+
+  $ cat >dune.lock/mypkg.pkg <<EOF
+  > (version 0.0.1)
+  > (source (copy $PWD/../external_sources))
+  > (build (run dune build --release --promote-install-file=true . @install))
+  > EOF
+
+  $ cat >dune <<EOF
+  > (library
+  >  (name foo)
+  >  (libraries mypkg.lib))
+  > EOF
+
+  $ cat >foo.ml <<EOF
+  > let () = Test_lib.x
+  > EOF
+
+  $ dune build @ocaml-index
+  Error: This rule defines a directory target "default/.pkg/mypkg/target" that
+  matches the requested path
+  "default/.pkg/mypkg/target/lib/mypkg/lib/cctx.ocaml-index" but the rule's
+  action didn't produce it
+  -> required by _build/default/.foo.objs/cctx.ocaml-index
+  -> required by alias ocaml-index
+  [1]