Add manual trigger for CI

[tim-barry]

Intended to allow running CI tests on PRs that are not directly targeted to master or a feature branch, without requiring CI on all such PRs.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 41.31%. Comparing base (c448e34) to head (a640e10).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #7268   +/-   ##
=======================================
  Coverage   41.31%   41.31%           
=======================================
  Files        2174     2174           
  Lines      190514   190514           
=======================================
+ Hits        78705    78712    +7     
+ Misses     105227   105219    -8     
- Partials     6582     6583    +1     

Flag	Coverage Δ
unittests	41.31% <ø> (+<0.01%)	⬆️

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[jordanschalm]

Not sure but I think we need to provide a way to communicate the branch we want to test here. We are running this from the Actions tab, not from a PR. How does the action know which branch/tag it is running CI against?

There is the default Use workflow from selector which selects which workflow file to use, but I'm not sure if that selection is the same variable as is used by (for example) the Checkout action (my impression from some brief reading is that they are different).

The CD workflow has a similar pattern and it configures a separate input, then uses it within the jobs defined in the workflow.

  workflow_dispatch:
    inputs:
      tag:
        description: 'Tag/commit'
        required: true
        type: string

[tim-barry]

Hm, I was assuming that the Use workflow from selector was the same used by the Checkout action; otherwise how does the checkout action know what to checkout at all, given the current ci.yml doesn't use the same inputs/tag field and doesn't specify which branch to run from?
Unfortunately I haven't been able to find clear information in github's documentation or elsewhere...

[jordanschalm]

how does the checkout action know what to checkout at all, given the current ci.yml doesn't use the same inputs/tag field and doesn't specify which branch to run from?

From their README:

    # The branch, tag or SHA to checkout. When checking out the repository that
    # triggered a workflow, this defaults to the reference or SHA for that event.
    # Otherwise, uses the default branch.
    ref: ''

My reading of this is that when the workflow is triggered from an event associated with a branch (PR push), then actions default to using the reference from the event. Otherwise it will use the repo's default branch.

[tim-barry]

@sjonpaulbrown The PR discussing manually running CI. To me it seems we would need to add a 'ref/commit/branch' field for the manual workflow to run on, similar to some other workflows, but I'm not sure how we would set it up such that it doesn't affect the regular CI runs.