Effectively navigating branch history (was: Re: [PATCH] config.c: Remove unused git_config_global() function)

[Stephen Bash <bash@genarts.com>]

----- Original Message -----
> From: "Junio C Hamano" <gitster@pobox.com>
> Sent: Tuesday, May 31, 2011 1:51:06 PM
> Subject: Re: [PATCH] config.c: Remove unused git_config_global() function
> 
> > Commit 8f323c00 (drop support for GIT_CONFIG_NOGLOBAL, 15-03-2011)
> > removed the git_config_global() function, among other things, since
> > it is no longer required. Unfortunately, this function has since
> > been unintentionally restored; I suspect by merge commit 25b86e45
> > (Merge branch 'jk/maint-config-alias-fix' into next, 25-05-2011).
> 
> Yeah, I think it was 1f9a980636 which was a merge between fb674d7 and
> 73546c0. I just compared the output between these two:
> 
> $ git diff fb674d7...73546c0 -- config.c ;# what the topic did
> $ git diff fb674d7 1f9a980 -- config.c ;# what was merged

Junio - I'd like to take a chance to learn from a master here if you don't mind.  I often find myself wanting to do the "what the topic did" operation but once the branch is merged and deleted, I have difficulty finding useful SHAs to diff.

So in an attempt to educate myself, I tried to track down fb674d7 and 1f9a980 (and failed miserably).  I can easily find 8f323c00 using 'git log -S git_config_global', but conceptually I want to trace children of 8f323c00 to see where it merged, and that seems ... complicated.  Do you mind walking through your thought process on this problem?

Thanks!
Stephen