Re: "git diff" does not show a diff for newly added, binary files

From: Jeff King <peff@peff.net>
Date: Apr 4, 2023, 15:39 UTC
Message-ID: <20230404153918.GB160693@coredump.intra.peff.net>
In-Reply-To: <3473764.PTxrJRyG3s@earendil>

On Tue, Apr 04, 2023 at 11:58:38AM +0200, Thorsten Otto wrote:

Show 18 quoted lines

> "git diff" does not show a diff for newly added, binary files
> 
> What did you do before the bug happened? (Steps to reproduce your issue)
> 
> $ git init .
> $ touch a
> $ git add a
> $ git commit -m "first commit"
> $ dd if=/dev/zero of=b count=1
> $ git add b
> $ echo hello > c
> $ git add c
> $ git diff --cached
> 
> What did you expect to happen? (Expected behavior)
> 
> I expected a binary diff for the new file, just like it is done
> when comparing two different, already committed revisions.

I responded elsewhere in the thread mentioning "git diff --binary", but note this part of the report is a little misleading. The difference is not showing newly added files versus committed revisions. The difference is between "git diff" and "git format-patch". If you commit the result above and then run:

  git diff HEAD^ HEAD

it will likewise not show the binary patch (unless you specify --binary). Likewise for "git show", etc. I think that format-patch is the only command with binary diffs turned on by default.

-Peff