Update how upload_to_pypi is defined

[astrofrog]

Prior to this PR, I think upload_to_pypi was potentially counter-intuitive because upload_to_pypi: false still means that sometimes things are uploaded to PyPI. I think it would be cleaner to simply specify that it is a boolean condition for the upload, defaulting to true if a v* tag is pushed.

I'm not sure if this will work though, as I don't know if a condition can be given as the default for the parameter. But I do think we should try and make it behave somehow like it is here, meaning that upload_to_pypi: false would never upload anything.

[ConorMacBride]

It might work if the condition is surrounded with ${{ }} but I have a feeling conditions are not supported there.

[astrofrog]

Should we make the parameter a string and then somehow evaluate it as a boolean later in the pipeline for it to work?

[astrofrog]

@ConorMacBride - I probably won't have time to try and dig deeper into this today so feel free to take over the PR if you like, if you agree that we should tweak this option.

[ConorMacBride]

A string would work. I can take a look later. I'll make upload_to_pypi accept 'true', 'false' and 'auto'. Or should we call it 'tag' instead of 'auto'?

[astrofrog]

I guess the question is how would a user then specify that they want to upload on all tags, not just ones starting with 'v'? Basically we need a way for users to pass a completely custom condition?

[ConorMacBride]

We could keep upload_to_pypi a boolean input and default to false. When the reusable workflow is called, it should be possible to do

uses: OpenAstronomy/github-actions-workflows/.github/workflows/tox.yml@main
with:
  upload_to_pypi: ${ github.event_name == 'push' && startsWith(github.event.ref, 'refs/tags/v') }

[ConorMacBride]

If we do that I think we should make upload_to_pypi be required (no default) to reduce confusion (e.g. why does the publish workflow not publish by default?)

[astrofrog]

@ConorMacBride yes we might have to just make it required. @Cadair, what do you think?

[ConorMacBride]

I've updated the upload_to_pypi input to have the following behaviour. (With some testing here: https://github.com/ConorMacBride/test-workflows/blob/main/.github/workflows/test_upload.yml)

upload_to_pypi

Whether to upload to PyPI after successful builds.
The default is to upload to PyPI when tags that start with v are pushed.
A boolean can be passed as true (always upload) or false (never upload)
either explicitly or as a boolean expression (${{ <expression> }}).

Alternatively, a string can be passed to match the start of a tag ref.
For example, 'refs/tags/v' (default) will upload tags that begin with v,
and 'refs/tags/' will upload on all pushed tags.

[astrofrog]

Nice! Thank you!

[ConorMacBride]

Merge?

[astrofrog]

@ConorMacBride - could you rebase to resolve the conflict? Then feel free to merge.