Re: [PATCH 2/2] Allow passing pipes for input pipes to diff --no-index

Jeff King [off-list ref] writes:

We'd sometimes wait several versions before that last step to give
people time to adjust scripts, etc. But in this case, I suspect it would
be OK to just flip it immediately. We don't consider "git diff" itself
part of the stable plumbing, and the --no-index part of it I would
consider even less stable. And AFAICT most people consider the current
behavior a bug because it doesn't behave like other diff tools.

The "git diff" proper gets no filenames from the command line and
the above strictly applies only to the no-index mode, with or
without the explicit "--no-index" option.

It was a way to give Git niceties like colored diffs, renames,
etc. to non-Git managed two sets of paths, and the primary reason
why we have it as a mode of "git diff" is because we chose not to
bother with interacting with upstream maintainers of "diff".  In an
ideal world, "GNU diff" and others would have learned things like
renames, word diffs, etc., instead of "git diff" adding "--no-index"
mode.

And that makes me agree that users expect "git diff --no-index" to
behave like other people's diff and that is more important than
behaving like "git diff" for that mode.