Broadcast frames over both data and attributes - #15121

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@pllim, is this truly a breaking change, or could this be regarded as a bug fix, to go in earlier than v6?

@lpsinger , your change log fragment says "feature" and we do not backport features, just bug fixes. If you want to rename the fragment, please squash your commits. I'll let coordinates maintainers decide though whether this is bug fix or new feature: @StuartLittlefair , @adrn , @eteq , @eerovaher , @mhvk

Done.

I think "feature" is appropriate here! I won't really have time to look in any detail until next week, but this is a very long-standing wish-list item! Still, I think it is involved enough -- and an API change, really (even if one we have wanted for a long time) that it is better not to backport.

Would you like me to switch the change log entry back to "feature"?

I'll leave that you y'all because bug fixes are allowed in feature release, so as far as I am concerned, it does not matter. But if you do end up renaming, please squash again. Sorry for the inconvenience!

Side question, do you have a sense of when astropy 6 will be released?

By the end of 2023, see https://github.com/astropy/astropy/wiki/Release-Calendar

p.s. Kudos to fixing not one, but five issues in one go. Thanks! 👏

I made this a "feature" again and I added a bit more motivation to the changelog entry.

I could see this as meriting a writeup in "What's New." What do you think?

Sure! I think broadcasting is very useful and should be in what's new. Thanks!

Side question, do you have a sense of when astropy 6 will be released?

By the end of 2023, see https://github.com/astropy/astropy/wiki/Release-Calendar

I see. I plan on using this capability (whether "feature" or "bug fix") in my multi-observatory observation planning project. The time horizon of that project means that I have a vested interest in treating this as a "bug" rather than a "feature" 😃

@lpsinger , what is your deadline?

@lpsinger , what is your deadline?

I'd like to submit a paper with working code using a stable Astropy release by about October, which is when the grant that is funding the work ends.

If you really need this in a bug fix release... is there a way to separate out the backward compatible stuff into a separate PR that can be backported?

If you really need this in a bug fix release... is there a way to separate out the backward compatible stuff into a separate PR that can be backported?

Where would you divide the line? It seems pretty atomic to me.

What about something like a feature flag (perhaps implemented as science state) to toggle the broadcasting on or off? Or a warning.

@mhvk et al., what do you think?

I wrote an extended example for "What's New".

Doctest failure sadly looks real:

Fixed now. There is a remaining test failure, but it looks like it is not related to this PR.

Thank you, all!

Re: #15121 (comment)

@lpsinger , how do you like to proceed here. Would an alpha be needed before we push out a regular RC as per https://github.com/astropy/astropy/wiki/Release-Calendar ?

Regardless, your changes would be released as part of astropy v6.0 and they would be available in the dev nightly wheel probably by tomorrow.

@lpsinger , how do you like to proceed here. Would an alpha be needed before we push out a regular RC as per https://github.com/astropy/astropy/wiki/Release-Calendar ?

The grant funding is over, and it was my fault due to getting stuck on the iterations for this PR. I don't think it matters. I can definitely work with the nightly builds in the mean time. But thanks for entertaining the possibility of an alpha release.

Okay. We will proceed normally then. Thank you!