Re: [PATCH] log: improve --follow following renames in merge commits

From: Miklos Vajna <vmiklos@collabora.com>
Date: Jun 4, 2026, 12:20 UTC
Message-ID: <aiFtpkk_xN1897IE@collabora.com>
In-Reply-To: <ahqDqSH7yfYVOOyE@collabora.com>

Hi Jeff,

On Sat, May 30, 2026 at 08:29:03AM +0200, Miklos Vajna <vmiklos@collabora.com> wrote:

> Could you please comment on this, if this tweaked rule and its
> implementation in the patch looks OK to you? Let me know if I should
> just wait some more.

Just to come back to this, the idea was to make the --follow behavior slightly more useful by not always assuming we should follow a first parent in merge commits, but see if only one parent has effective changes to the followed file, and if so, follow that one.

I did this by doing a diff on the followed path in each parent, then mark the parent as "interesting" if DIFF_FILE_VALID() says so. This is true if the file is touched or the rename happens inside the merge commit (vs that parent), but it's not true if the file is really not touched or the file only shows up as an addition. And if we have only have one interesting parent, then switch to this, even if it's not the first parent. With this rule, I think we address your worry case about "making some other cases" worse and this still works for the subtree case, and this is relatively easy to do.

What do you think?

Thanks,

Miklos