`fs-io` and `top-closure` packages fail to install from opam using `with-tests`

[shonfeder]

This appears to be a regression since the release of 3.20, initially reported at ocaml/opam-repository#29070 (comment)

Errors for fs-io look like

The following actions will be performed:
=== recompile 1 package
  - recompile fs-io 3.21.0~alpha3 (pinned)

<><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
Processing  2/4: [fs-io: dune build]
+ /home/opam/.opam/5.0/bin/dune "build" "-p" "fs-io" "-j" "11" "@install" "@runtest" (CWD=/home/opam/.opam/5.0/.opam-switch/build/fs-io.3.21.0~alpha3)
- File "test/blackbox-tests/test-cases/build-info/dune", line 4, characters 11-26:
- 4 |   (package dune-build-info)))
-                ^^^^^^^^^^^^^^^
- Error: Package dune-build-info does not exist
- File "test/blackbox-tests/test-cases/cinaps/dune", line 4, characters 11-17:
- 4 |   (package cinaps)))
-                ^^^^^^
- Error: Package cinaps does not exist
- File "test/blackbox-tests/test-cases/ctypes/dune", line 21, characters 11-17:
- 21 |   (package ctypes)))
-                 ^^^^^^
- Error: Package ctypes does not exist
- File "test/blackbox-tests/test-cases/ctypes/dune", line 10, characters 11-17:
- 10 |   (package ctypes)))
-                 ^^^^^^
- Error: Package ctypes does not exist
- File "test/blackbox-tests/test-cases/ctypes/dune", line 26, characters 11-19:
- 26 |   (package integers)))
-                 ^^^^^^^^
- Error: Package integers does not exist
- File "test/blackbox-tests/test-cases/inline_tests/dune", line 4, characters 11-21:
- 4 |   (package ppx_expect)))
-                ^^^^^^^^^^
- Error: Package ppx_expect does not exist
- File "test/blackbox-tests/test-cases/inline_tests/dune", line 13, characters 11-17:
- 13 |   (package stdune)))
-                 ^^^^^^
- Error: Package stdune does not exist
- File "test/blackbox-tests/test-cases/ppx/dune", line 4, characters 11-17:
- 4 |   (package ppxlib)
-                ^^^^^^
- Error: Package ppxlib does not exist
- File "test/blackbox-tests/test-cases/utop/dune", line 3, characters 11-15:
- 3 |   (package utop)))
-                ^^^^

IIUC, this is just showing that a bunch of tests are being run for packages which should not be be exercised by the fs-io package's tests. The tests also hang.

[shonfeder]

To reproduce, you can run

cd $(mktemp -d)
git clone --recursive "https://github.com/ocaml/opam-repository.git" && cd "opam-repository" && git fetch origin "refs/pull/29070/head" && git reset --hard a95df901
git fetch origin master
git merge --no-edit 810e1f14b7fa6411c66a3549f4c2aff47c52fc36
cat > ../Dockerfile <<'END-OF-DOCKERFILE'
FROM ocaml/opam:debian-13-ocaml-5.0@sha256:0d8930231b169f32662a9574b55543433f79e1bed3bac1f340e5dddf0cb7bfee
USER 1000:1000
WORKDIR /home/opam
RUN sudo ln -f /usr/bin/opam-dev /usr/bin/opam
RUN opam init --reinit -ni
RUN opam option solver=builtin-0install && opam config report
ENV OPAMDOWNLOADJOBS="1"
ENV OPAMERRLOGLEN="0"
ENV OPAMPRECISETRACKING="1"
ENV CI="true"
ENV OPAM_REPO_CI="true"
RUN rm -rf opam-repository/
COPY --chown=1000:1000 . opam-repository/
RUN opam repository set-url --strict default opam-repository/
RUN opam update --depexts || true
RUN opam pin add -k version -yn fs-io.3.21.0~alpha3 3.21.0~alpha3
RUN opam reinstall fs-io.3.21.0~alpha3; \
    res=$?; \
    test "$res" != 31 && exit "$res"; \
    export OPAMCLI=2.0; \
    build_dir=$(opam var prefix)/.opam-switch/build; \
    failed=$(ls "$build_dir"); \
    partial_fails=""; \
    for pkg in $failed; do \
    if opam show -f x-ci-accept-failures: "$pkg" | grep -qF "\"debian-13\""; then \
    echo "A package failed and has been disabled for CI using the 'x-ci-accept-failures' field."; \
    fi; \
    test "$pkg" != 'fs-io.3.21.0~alpha3' && partial_fails="$partial_fails $pkg"; \
    done; \
    test "${partial_fails}" != "" && echo "opam-repo-ci detected dependencies failing: ${partial_fails}"; \
    exit 1

END-OF-DOCKERFILE
docker build -f ../Dockerfile -t fs-io-debug .
docker run -it --rm fs-io-debug bash
opam reinstall --with-test --verbose fs-io.3.21.0~alpha3

[Alizter]

I think we need to remove the with-tests stuff that is generated in the opam files. This will require introducing a template opam file for these packages.

What is happening is that the opam file has instructions to do dune build @runtest when encountering the opam file for these packages and not all of our tests are attached to a package yet, so some unrelated tests end up getting run. This can be fixed by removing this step like we do for the other libraries.

[Alizter]

What's interesting about running dune build -p fs-io @runtest is that it causes dune to hang and I'm not quite sure why. @rgrinberg any ideas?

[rgrinberg]

LIkely a dependency cycle that turns into an infinite loop.