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

From: George Shammas <georgyo@gmail.com>
Date: Jul 31, 2018, 15:03 UTC
Message-ID: <CAF1Ko+FNfjWMteccfKDBjPEW76rGBLQkGb1icUHmzEZ0fKQJBA@mail.gmail.com>
In-Reply-To: <CAF1Ko+FBP5UmETmh071dvn9iv8-N-3YgaP61q-4jQvxFdN0GTA@mail.gmail.com>

Bisecting around, this might be the commit that introduced the breakage.

https://github.com/git/git/commit/d8febde

I really hope that it hasn't been broken for 5 years and I am just doing something wrong.

On Tue, Jul 31, 2018 at 10:09 AM George Shammas <georgyo@gmail.com> wrote:

Show 27 quoted lines

> At work, we recently updated from a massively old version of git (1.7.10)
> to 2.18. There are a few code bases that use subtrees, and they seem to
> have completely broke when trying to merge in updates.
>
> I have confirmed that it works correctly in 1.7.10.  The 2.18 behavior is
> clearly incorrect.
>
> git init
> echo init > test
> git add test
> git commit -m init
>
> git remote add tig https://github.com/jonas/tig.git
> git fetch tig
> git merge -s ours --no-commit --allow-unrelated-histories tig-2.3.0
> git read-tree --prefix=src/ -u tig-2.3.0
> git commit -m "Get upstream tig-2.3.0"
> # Notice how the history are merged, and that the source from the upstream
> repo is in src
>
> echo update > test
> git commit -a -m "test"
>
> git merge -s subtree tig-2.4.0
> # Boom, in 2.18 instead of merging into the subtree, it just deletes
> everything in the repository, which is clearly the wrong behavior.
>