Subject: Re: Salvaging borked project history

From: Junio C Hamano <[email-masked]>
Date: Thu, 26 Feb 2015 10:56:33 -0800

Mason <[email-masked]> writes:

> Thanks! At least now, I see the light at the end of the tunnel.
>
> I fetched linux-stable.git inside our repo.
> I created ~300 patches using git format-patch -1 in a loop.
> I can now run 'git am --3way $IGNORE *.patch'
>
> IGNORE is used to --exclude the directories I'm not interested in.
>
> Note: it seems --exclude=arch/mips and --exclude=arch/mips/ are
> not sufficient, I need to write --exclude=arch/mips/* for git-apply
> to ignore changes to files inside arch/mips.
>
> Is that expected behavior?

I have no idea; at least to me, "--exclude" option to "git apply"
was invented to name individual paths, not patterns, and I wouldn't
be surprised if glob working were merely by accident not by design.

> Another nit: if a patch contains only changes to files inside arch/mips
> then git-apply will create an "empty commit" (one with no diff). Is there
> an option to say "skip empty patches"?

"git am --skip" perhaps?

"git am" may pass the "--exclude/--include" options to "git apply"
but I wouldn't be surprised if that support was added without
thinking.  Perhaps the reason why you discovered that it needed a
lot more thinking to properly integrate these options to "git am"
only now is because hardly anybody uses it ;-).  Not just passing
these options, the code in "git am" to react to the result of patch
application to avoid the issue you observed when these options are
passed need to be adjusted by changes that started passing them, but
I do not think they did, cf. 77e9e496 (am: pass exclude down to
apply, 2011-08-03).

> One more thing: "regular" diff -q returns 0 when the files are identical,
> and 1 when they differ. It seems git diff -s does not have that behavior.
> Is that by design?

"diff -s" may be accepted but it is an idiotic thing for a user to
say.  The "-s" option is to squelch output from "log" and friends,
and it is exposed to "diff" only because these two families of
commands share the command line parser.