Re: Force git diff to create a binary patch?

Jason Xu [off-list ref] writes:

quoted

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,

quoted

  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".