From: Martin Storsjö <martin@martin.st>
Date: Sat, 09 Sep 2023 20:42:41 GMT
Subject: Regression in git diff with stdin, with -R
Message-ID: <d42579a0-f438-9b4c-97e4-58724dbe4a4@martin.st>

Hi,

Since 1e3f26542a6ecd3006c2c0d5ccc0bae4a700f7e5, "diff --no-index: support 
reading from named pipes", one usecase about diffing with stdin has 
broken.

I see that this patch was preceded by adding some extra tests around 
diffing with stdin - but one case seem to have been missed.

"git diff --no-index - regularfile" still works fine as it did before, 
also "git diff --no-index regularfile -" also still works. (I.e. stdin can 
either be the first or second file argument - both work.)

However if using the -R option to reverse the diff direction, i.e. "git 
diff --no-index -R - regularfile" or "git diff --no-index -R regularfile 
-", I'm now getting the following error:

     fatal: stat '-': No such file or directory

// Martin