paths-filter VS changed-files

I also set up recently the policy to onl use merge commits on stable branch, as otherwise the path filter^1 in the workflows would not detect correctly which files changed in a PR.

[1] https://github.com/dorny/paths-filter

I truly don't understand why this isn't more widely discussed (I've seen several "GH Actions Gotchas" where this isn't mentioned). Many of the community actions also seem to be designed to run as short jobs to paper around missing features (for ex: https://github.com/dorny/paths-filter ), that end up eating up an enormous amount of your minutes budget.

If that isn’t sufficient, there are a number of third party workflow steps that enable conditional builds with extra flexibility like https://github.com/dorny/paths-filter

You can use paths-filter to give yourself a bunch of conditional outputs to test against for separate jobs.

That's brilliant. dorny/paths-filter looks like it can eliminate my enumerate job, and then I don't have to concern myself with all this data passing between jobs.

There’s an awkward gotcha/incompatibility between “Required status checks” and workflows that get skipped [1], eg due to setting a “paths” property of a push/pull_request workflow trigger [2].

The checks associated with the workflow don’t run and stay in a pending state, preventing the PR from being merged.

The only workaround I’m aware of is to use an action such as paths-filter [3] instead at the job level.

A further, related frustration/limitation - you can _only_ set the “paths” property [2] at the workflow level (i.e. not per-job), so those rules apply to all jobs in the workflow. Given that you can only build a DAG of jobs (ie “needs”) within a single workflow, it makes it quite difficult to do anything non trivial in a monorepo.

[1]: https://docs.github.com/en/repositories/configuring-branches...

[2]: https://docs.github.com/en/actions/using-workflows/workflow-...

[3]: https://github.com/dorny/paths-filter

We are interested in running a linter only against the modified files. Let's say, we take a look at the provided repo, if I update dags/dummy.py I don't want to waste time and resources running the linter against main.py. For this purpose we use Paths Filter GitHub Action, which is very flexible.

In the spirit of the #ActionsHackathon21, you can see I'm taking advantage of the checkout action GitHub provides and the Paths Filter action by dorny to create the desired workflow. I'm also using the Gistblog Action I created for this hackathon which handles managing all the blog posts as Gists. I'd like to explore Composite actions soon to see if I can reduce all of this to a single action making setup even easier.

We need to add two additional steps. The first one is to retrieve all new files, and the second one is to run the enhanced config only on the new files. In this example the third-party GitHub Action called changed-files is used to obtain the new files. In the GitHub Marketplace for Actions, there is a considerable number of similar actions with similar functionality. You can choose the one that suits you best, as the functionality is more or less the same for all of them.

I determined this after dozens of attempts working with the other GitHub Action, tj-actions/changed-files which feeds a list of modified files to clang-format-lint.

GitHub actions has actions that do similar, I’ve used this one before with great success: https://github.com/tj-actions/changed-files

You could also clean up your changed files job by using this (https://github.com/tj-actions/changed-files) or something similar. That would at least make it easier to understand what it's supposed to be doing. You can use it to get the directories containing any changed package.json files. Then use that output as as a matrix input.

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