Re: Force git diff to create a binary patch?

From: Junio C Hamano <gitster@pobox.com>
Date: Jul 14, 2020, 04:34 UTC
Message-ID: <xmqq5zaqn29t.fsf@gitster.c.googlers.com>
In-Reply-To: <CAGPh-qPyTNidqT=K-U8iYtG3udFZVFBhE1RyA1AZ1qEqN_NnZw@mail.gmail.com>

Jason Xu <jasonx98@gmail.com> writes:

Show 12 quoted lines

>> The description for the --binary option reads as follows:
>>
>>   In addition to --full-index, output a binary diff that can be applied
>>   with git-apply. Implies --patch.
>>
>> So we need to fix either the documentation or the code.
>>
>> I looked into what it takes to fix the code to do this; it's fairly
>> straightforward, but it does cause some testsuite failures which assume
>> the current behavior and will likely involve a small series.  So if
>> other folks agree, I'm happy to pick this up in the next couple of weeks
>> and add support for it that would hopefully hit Git 2.29.

I am not convinced.

The "--binary" option was invented as a way to tell Git to produce something that can be applied, where Git stopped at saying "binary files differ". So a commit that touches two paths, one text and the other binary, used to produce a textual patch for one and a useless "binary files differ" for the other in "git show". Such a commit can be made more useful with "git show --binary" to tell the former to still produce textual and readable patch while showing the xdelta based "binary patch" Git invented.

So, no, I am less convinced "--binary" that forces "all paths are binary, so show binary patch" is a good idea.

And viewed with the knowledge of that history,

>>   In addition to --full-index, output a binary diff that can be applied
>>   with git-apply. Implies --patch.

this description is correct---the choice is not between "showing a binary diff and showing a useless textual diff"; the choice is between showing "binary files differ" and appliable "binary patch".