Re: path-restricted log vs. subtree merges

From: Jeff King <peff@peff.net>
Date: Mar 17, 2025, 17:43 UTC
Message-ID: <20250317174343.GA704253@coredump.intra.peff.net>
In-Reply-To: <Z9WSbUQw4VBQiOqi@ugly>

On Sat, Mar 15, 2025 at 03:45:01PM +0100, Oswald Buddenhagen wrote:

Show 12 quoted lines

> in my quest to prepare for hacking git-gui, i ran
> 
>   cd .../git/git-gui
>   git log .
> 
> the result is ... unhelpful. apart from a few commits that were done
> directly in the git repo, there are only merges. notably, there is no
> trace of the commits that are being merged (and the way gitk presents
> this partial log is even more unhelpful).
> 
> i'm speculating that this is the result of git log not handling the
> subtree merges in any way, with somewhat predictable consequences.

Yes, the merged-in paths and the paths in the original commits are different. So the merge will update path "git-gui/git-gui.sh", etc, but the individual commits are touching "git-gui.sh" at the root of the tree (in the git-gui repository).

Leaving aside for a moment how --follow and other tooling could help, the workaround in this case is:

  git log -- git-gui/ git-gui.sh lib/

You need to ask for the paths you care about at the root-level (since that's what the individual commits from the git-gui repo will have). But you also need to include git-gui/; otherwise history simplification will not go down the side branches from the git-gui repo (you can also use --full-history, but that would include a lot of irrelevant stuff). And you need to use "--" before the paths, since the rev/path dwim logic will only treat an argument as a path if it is present in the working tree (which the latter two paths are not).

-Peff