Re: git merge -s subtree seems to be broken.

From: George Shammas <georgyo@gmail.com>
Date: Jul 31, 2018, 15:56 UTC
Message-ID: <CAF1Ko+HAusyCOaTWT-cT0DW0MoJdDv3RdoW+U25QRqaacCAh5w@mail.gmail.com>
In-Reply-To: <xmqqtvofcsgc.fsf@gitster-ct.c.googlers.com>

While debugging this, I did try -X subtree=src/ however the effect was the same.

On Tue, Jul 31, 2018 at 11:53 AM Junio C Hamano <gitster@pobox.com> wrote:

Show 24 quoted lines

> George Shammas <georgyo@gmail.com> writes:
>
> > Bisecting around, this might be the commit that introduced the breakage.
> >
> > https://github.com/git/git/commit/d8febde
>
> Interesting.  I've never used the "-s subtree" strategy without
> "-Xsubtree=..." to explicitly tell where the thing should go for a
> long time, so I am not surprised if I did not notice if an update to
> the heuristics made long time ago had affected tree matching.
>
> d8febde3 ("match-trees: simplify score_trees() using tree_entry()",
> 2013-03-24) does touch the area that may affect the subtree matching
> behaviour.
>
> Because it is an update to heuristics, and as such, we need to be
> careful when saying it is or is not "broken".  Some heuristics may
> work better with your particular case, and may do worse with other
> cases.
>
> But from the log message description, it looks like it was meant to
> be a no-op simplification rewrite that should not affect the outcome,
> so it is a bit surprising.
>