Re: merge renamed files/directories?

From: Shawn O. Pearce <spearce@spearce.org>
Date: May 6, 2008, 02:12 UTC
Message-ID: <20080506021202.GN29038@spearce.org>
In-Reply-To: <32541b130805051858u7b8f1cd7qd34fdf50c1f849d0@mail.gmail.com>

Avery Pennarun <apenwarr@gmail.com> wrote:

Show 16 quoted lines

> On 5/5/08, Shawn O. Pearce <spearce@spearce.org> wrote:
> >
> > `git pull -s subtree mylib` ?
> 
> First, I thought: wow!  How can that possibly work?  These guys are geniuses!
> 
> Then I found out that git-merge-subtree is a git builtin, and git.c says this:
> 
>   { "merge-recursive", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
>   { "merge-subtree", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
> 
> And then my head exploded. :)
> 
> Still scraping the pieces of my brain back off the floor... but does
> this mean the subtree merge strategy would fail exactly like
> merge-recursive when new files are created?

Nope. If you go look at cmd_merge_recursive you will see it has different behavior based upon the name it was invoked as, even though it is the same C function and has the same implementation.

If it is started with the name "merge-subtree" it tries to find a matching subtree prefix to insert in front of all names, or to remove from all names, such that a merge will correctly fully include a set of files in a subdirectory, or full pull out a set of files from a subdirectory.

Junio is the genius that implemented this. Works quite well for this library->application merge case that I think you were trying to describe.

-- 
Shawn.