[Merged by Bors] - fix: Stop cancelling builds of master

[edegeltje]

As mentioned on zulip, the building process on master can get cancelled on occasion. this PR hopes to fix that issue.

---

[github-actions]

PR summary 9a851a4706

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference

---

Declarations diff

No declarations were harmed in the making of this PR! 🐙

You can run this locally as follows

## summary with just the declaration names:
./scripts/declarations_diff.sh <optional_commit>

## more verbose report:
./scripts/declarations_diff.sh long <optional_commit>

The doc-module for script/declarations_diff.sh contains some details about this script.

---

No changes to technical debt.

You can run this locally as

./scripts/technical-debt-metrics.sh pr_summary

• The relative value is the weighted sum of the differences with weight given by the inverse of the current value of the statistic.
• The absolute value is the relative value divided by the total sum of the inverses of the current values (i.e. the weighted average of the differences).

[bryangingechen]

I think we need a check that the ref is not contained on the master branch, not that it is not equal to master itself. For reference, here's the log of a run that canceled 9082fa7 on master.

[bryangingechen]

Thanks for this! Let me see if I can test this out in my fork before we merge this.

[bryangingechen]

After testing, I'm pretty sure that the concurrency feature does what we want it to.

I think what you're doing is equivalent, but GitHub's docs use something like this to avoid cancel-in-progress on a certain branch:

Suggested change

	# workflows on master get more expressive labels
	group: ${{ github.workflow }}-${{ github.ref }}.${{(github.ref == 'refs/heads/master' && github.run_id) || ''}}
	# cancel any running workflow with the same label
	cancel-in-progress: true
	group: ${{ github.workflow }}-${{ github.ref }}
	# cancel any workflows with the same label not running on master
	cancel-in-progress: ${{ github.ref != 'refs/heads/master' }}

To me it looks somewhat easier to understand, but I don't mind if this is merged as is.

Thanks again for getting this fixed!
bors d+

[edegeltje]

the reason i did this different from the example is because in a concurrency group, only one workflow runs at a time. That means that with the suggested version, it would not build multiple versions of master at the same time, since they're in the same concurrency group.

bors r+

[mathlib-bors]

✌️ edegeltje can now approve this pull request. To approve and merge a pull request, simply reply with bors r+. More detailed instructions are available here.

[mathlib-bors]

Pull request successfully merged into master.

Build succeeded:

• Build
• Lint style