Re: [PATCH v5] subtree: fix split processing with multiple subtrees present

From: Zach FettersMoore <zach.fetters@apollographql.com>
Date: Nov 30, 2023, 21:01 UTC
Message-ID: <CAEWN6q14sd-KmMOgmKWqnKWPNUeW7MN5T=PhrkkN5d0VXQEohA@mail.gmail.com>
In-Reply-To: <CAP8UFD1rd+q-dC_w2VgZ_jC++LDeF6gu5wDcbQzSuhU1ksfBpA@mail.gmail.com>

>> To see this in practice you can use the open source GitHub repo
>> 'apollo-ios-dev' and do the following in order:
>>
>> -Make a changes to a file in 'apollo-ios'A and 'apollo-ios-codegen'

> It looks like there is a spurious A after 'apollo-ios' in the line above.

Thanks for catching that, definitely a typo on my part.

>> directories
>> -Create a commit containing these changes
>> -Do a split on apollo-ios-codegen
>> - git subtree split --prefix=apollo-ios-codegen --squash --rejoin

Show 8 quoted lines

> I might be doing something stupid or wrong, but I get the following:
>
> $ git subtree split --prefix=apollo-ios-codegen --squash --rejoin
> fatal: could not rev-parse split hash
> cc70a7d49e84696f0df210710445784c504ed748 from commit
> 360f068ea0d57f250621ab7dbe205313f52a0e98
> hint: hash might be a tag, try fetching it from the subtree repository:
> hint: git fetch <subtree-repository> cc70a7d49e84696f0df210710445784c504ed748

Updated this to include doing a fetch to ensure all remote repo info is available locally.

>> -Do a split on apollo-ios
>> - git subtree split --prefix=apollo-ios --squash --rejoin

Show 11 quoted lines

> Same issue:
>
> $ git subtree split --prefix=apollo-ios --squash --rejoin
> fatal: could not rev-parse split hash
> b852c0aa1fd5ab9e1323da92b606ad3f2211e111 from commit
> b48030c3eb6e2faf4bff981c5c63ca72aceecdfa
> hint: hash might be a tag, try fetching it from the subtree repository:
> hint: git fetch <subtree-repository> b852c0aa1fd5ab9e1323da92b606ad3f2211e111
>
> I didn't try to get farther than this, as it seems that some
> instructions might be missing.

Same as above, added extra instruction to do a fetch first.

Also added a little extra info that the issue may present after the first split in the instructions depending on the current state of the repo being used. Also added a way to do the same steps with the changes applied to see that it resolves the issue.

Show 9 quoted lines

>> So this commit makes a change to the processing of commits for the
>> split command in order to ignore non-mainline commits from other
>> subtrees such as apollo-ios in the above breakdown by adding a new
>> function 'should_ignore_subtree_commit' which is called during
>> 'process_split_commit'. This allows the split/rejoin processing to
>> still function as expected but removes all of the unnecessary
>> processing that takes place currently which greatly inflates the
>> processing time. In the above example, previously the final split
>> would take ~10-12 minutes, while after this fix it takes seconds.

> Nice!
>
> Except for the above issues in the commit message, the rest of the
> patch looks good to me, thanks!

Great! Thanks for the review and guidance!