Re: RFH - git-log variant that _does_ search through diffs

[Jeff King <peff@peff.net>]

On Tue, Jun 30, 2009 at 11:05:08AM -0700, Eric Raible wrote:

> What I _really_ want is the subset of all commits containing foo
> who's oneline commit message doesn't match a given regexp.
> 
> So I'm used something like this to extract the commits of interest:
> 
> git log -z -p | perl -0ne 'print if /^[-+].*foo/m' | tr '\0' '\n' |
> grep "^commit [0-9a-f]" | awk '{print $2}' |
> xargs -n1 git log --pretty=oneline -1 |
> grep -v dont_want

I think you can do this a little more simply and efficiently as:

  git log -z -p --format='GREP: %s' |
    perl -0ne 'print if /^[-+].*foo/m && !/^GREP:.*dont_want/' |
    tr '\0' '\n'

(though note that --format is new as of 1.6.3, I think; before that you
have to use "--pretty=format:"). Many fewer process invocations, and
less typing, though still easy to mess up. At one point I had considered
writing small wrapper scripts that understood the log output so you
could say:

  git log -z -p | filter-author $A | filter-diff $D | filter-subject $S

which is nicely readable and Unix-y, but is really _slow_ compared to
git doing it all in a single process. I think a "--grep-subject" and a
"--grep-diff" (aka "--search") are the only things that are missing now,
and those would both be pretty easy to implement.

-Peff