On 2023-01-19 at 18:06:17, Jack Adrian Zappa wrote:
> Here is the filled out form for submitting a bug report:
> 
> What did you do before the bug happened? (Steps to reproduce your issue)
> 
>   At the command line, I typed the following command:
> 
>   $ git diff --no-index --word-diff --color=always <(od -An -t x1
> -w10000000000 file1.txt) <(od -An -t x1 -w10000000000 file2.txt)
> 
> What did you expect to happen? (Expected behavior)
> 
>   I expected to see the diff of the two files.
> 
> What happened instead? (Actual behavior)
> 
>   Instead I saw this:
> 
>   error: Could not access '/proc/1961/fd/63'
> 
> What's different between what you expected and what actually happened?
> 
>   The difference is that I would get the difference between the two
> files as opposed to a critical failure message.

Thanks for the report.  This has come up before (and I attempted a
patch), but the ultimate problem here is that the /proc/PID/fd/* files
are symlinks on Linux, and instead of dereferencing symlinks, Git tries
to read them and print where they point to.  That doesn't work in this
case because the symlinks are symlinks to anonymous pipes, which can't
be resolved.

On other systems, the behaviour may be different because those files may
be represented differently.

My patch attempted to solve this by simply opening the contents instead
of stat'ing them as normal, but I think we found some edge cases and it
didn't get finished.  Note that this behaviour is what plain diff does
because it doesn't handle symlinks at all.
-- 
brian m. carlson (he/him or they/them)
Toronto, Ontario, CA