[PATCH v2 0/2] Do not skip tagged revisions in the GitHub workflow runs

Whenever a GitGitGadget Pull Request is sent to the Git mailing list, a tag is pushed to gitgitgadget/git to commemorate that iteration.

The push event caused for that triggers the CI/PR workflow, and reveals a pretty old bug where the windows-build steps are skipped for tagged revisions, but the windows-test steps are not (and will therefore fail).

That means, of course, that every GitGitGadget PR is marked with a failed test once it is submitted.

This patch series is designed to address this issue, and is based on am/ci-wsfix (the initial round was based on dd/ci-swap-azure-pipelines-with-github-actions but would now cause merge conflicts).

Changes since v1:

 * Rather than returning early from skip_branch_tip_with_tag(), we now skip
   the function call altogether when run in a GitHub workflow.
 * The intention of the tag skipping was replicated by introducing another
   check in ci-config: is there a successful workflow run for the same
   commit (or at least for the same tree)? If yes, skip, referring to that
   successful run.

Johannes Schindelin (2):
  ci: skip GitHub workflow runs for already-tested commits/trees
  ci: do not skip tagged revisions in GitHub workflows

 .github/workflows/main.yml | 39 +++++++++++++++++++++++++++++++++++++-
 ci/lib.sh                  |  2 ++
 2 files changed, 40 insertions(+), 1 deletion(-)

base-commit: 055747cd75c0904cc8122e5c12bd45e9f4743c30
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-619%2Fdscho%2Fgithub-workflows-and-tags-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-619/dscho/github-workflows-and-tags-v2
Pull-Request: https://github.com/gitgitgadget/git/pull/619

Range-diff vs v1:

 -:  ---------- > 1:  914868d558 ci: skip GitHub workflow runs for already-tested commits/trees
 1:  d9823f82ee ! 2:  931a2b8482 ci: fix GitHub workflow when on a tagged revision
     @@ Metadata
      Author: Johannes Schindelin <Johannes.Schindelin@gmx.de>
      
       ## Commit message ##
     -    ci: fix GitHub workflow when on a tagged revision
     +    ci: do not skip tagged revisions in GitHub workflows
      
          When `master` is tagged, and then both `master` and the tag are pushed,
          Travis CI will happily build both. That is a waste of energy, which is
          why we skip the build for `master` in that case.
      
     -    However, our GitHub workflow does not trigger on tags, therefore, this
     -    logic results in a missing build for that revision.
     +    Our GitHub workflow is also triggered by tags. However, the run would
     +    fail because the `windows-test` jobs are _not_ skipped on tags, but the
     +    `windows-build` job _is skipped (and therefore fails to upload the
     +    build artifacts needed by the test jobs).
      
     -    Even worse: the run would _fail_ because we would skip the Windows
     -    build, there are no artifacts to publish, and therefore no artifacts to
     -    download in the Windows test jobs.
     +    In addition, we just added logic to our GitHub workflow that will skip
     +    runs altogether if there is already a successful run for the same commit
     +    or at least for the same tree.
      
     -    Let's just change the GitHub workflow to skip the logic to skip
     -    revisions that are tagged.
     +    Let's just change the GitHub workflow to no longer specifically skip
     +    tagged revisions.
      
          Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
      
       ## ci/lib.sh ##
     -@@
     - # Library of functions shared by all CI scripts
     - 
     - skip_branch_tip_with_tag () {
     -+	test -z "$DONT_SKIP_TAGS" || return 0
     - 	# Sometimes, a branch is pushed at the same time the tag that points
     - 	# at the same commit as the tip of the branch is pushed, and building
     - 	# both at the same time is a waste.
      @@ ci/lib.sh: then
     + 	CI_REPO_SLUG="$GITHUB_REPOSITORY"
     + 	CI_JOB_ID="$GITHUB_RUN_ID"
       	CC="${CC:-gcc}"
     ++	DONT_SKIP_TAGS=t
       
       	cache_dir="$HOME/none"
     -+	DONT_SKIP_TAGS=t
       
     - 	export GIT_PROVE_OPTS="--timer --jobs 10"
     - 	export GIT_TEST_OPTS="--verbose-log -x"
     +@@ ci/lib.sh: good_trees_file="$cache_dir/good-trees"
     + 
     + mkdir -p "$cache_dir"
     + 
     ++test -n "${DONT_SKIP_TAGS-}" ||
     + skip_branch_tip_with_tag
     + skip_good_tree
     +