Re: Moving etc/NEWS around causing release branch merge to fail again

[Stefan Kangas <stefankangas@gmail.com>]

Eli Zaretskii <eliz@gnu.org> writes:

> What happened, exactly?  Please tell more about what you saw.

I saw the automatic merge fail with this error message:

    etc/NEWS has been modified

> Did you succeed in understanding the reason(s)?

For some reason, git succeeds in merging NEWS without any conflicts, and
then admin/automerge croaks because of it (see below).  Perhaps it is
related to the merge errors fixed in f1840cf12fda7f?  I don't know.

If it happens again, I hope to understand more about what is going on.
Should anyone want to dig in, just say this on master:

    git reset --hard 8036739c1bb6fa^ # warning: hard reset
    ./admin/automerge -r -n1

Fix the conflicts in typescript-ts-mode.el and lisp/treesit.el, and
then:

    ./admin/automerge -n1

>> BTW, when doing manual merges, can everyone please try to make sure that
>> etc/NEWS is *not* modified, or fix it manually.
>
> You mean, the merge to NEWS.29 on master?  Which NEWS should not be
> modified, and what do you mean by "manual merges"?

When I say manual merges, I mean those carried out using something like:

    emacs -Q -l admin/gitmerge.el -eval '(gitmerge "emacs-29")'

After a merge from the release branch (emacs-NN) to master, the etc/NEWS
file should never be modified.  Only the etc/NEWS.NN file should have
been modified.  Otherwise, it needs to be fixed manually.

See also these lines in admin/automerge:

    ## FIXME it would be better to trap this in gitmerge.
    ## NEWS should never be modified, only eg NEWS.26.
    git diff --stat --cached origin/master | grep -q "etc/NEWS " && \
        die "etc/NEWS has been modified"