docs: renaming formula requires two commits

[abitrolly]

Using git mv to rename formula will break CI. Formula needs to be copied and old one removed in two separate commits.

See Homebrew/homebrew-core#231234 (comment) for details.

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same change?
• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes? Here's an example.
• Have you successfully run brew style with your changes locally?
• Have you successfully run brew typecheck with your changes locally?
• Have you successfully run brew tests with your changes locally?

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[Bo98]

That modified bottle block warning is very new so seems more likely a bug with that? Dropping the bottle block for renames is expected because we don't support renames on bottle level (so old bottles don't work).

So renames can work in a single commit, as long as git is able to detect it as a rename. If you've made significant changes to the formula that makes git not think that, you probably want to have a dedicated (new formula) commit anyway instead of trying to hide the changes in a rename.

[abitrolly]

The bottles are regenerated in a separate PR, right?

Perhaps the PR bot could detect renames from the PR title and don't block the PR in case the bottle section was removed from rename.

[carlocab]

Technically it doesn't really block the PR, despite the red status.

But I agree that we should probably just fix the brew check-bottle-modification command so that it can handle renamed formulae in a single commit. A quick-and-dirty fix would make its failure not make CI red (but still post the comment, and acknowledge the possibility of false positives).

[carlocab]

Oh, actually, maybe it's not the bottle block check?

See Homebrew/homebrew-core#230831.

The bottle block check doesn't complain about the rename being done in a single commit, but the commit style check does complain about the fact that a single commit modifies two formulae.

[Bo98]

the commit style check does complain about the fact that a single commit modifies two formulae.

That's an example of subtantial enough changes that git isn't detecting that as a rename. Renames work fine: Homebrew/homebrew-core#196439.

The increased size of our bottle block does confuse git more nowadays though. Though Homebrew/homebrew-core#231234 still is detected as a rename despite all that. You can see commit style passes fine: Homebrew/homebrew-core@7419276

The bottles are regenerated in a separate PR, right?

No, they're pushed to the same PR during merge

[carlocab]

Ah, yes, I see. We can fix this for check-bottle-modification with Homebrew/homebrew-core#231336.

[abitrolly]

Now I need to check if the fix works to remove double commit advice. "remove bottles" instruction is still needed.

[MikeMcQuaid]

Passing on this, the advice is not desirable. We should instead fix it so this is not required.