Apparently 2.34:
* flipped around the "auto-merging" and "CONFLICT" messages on stdout,
so just match the second one with wildcards around to ignore the
location of the first
* changed the casing and content of everything after the `error` line
on stderr, so just ignore it all (none of it's actually useful
anyway)
If a PR is updated and has extent forward-ports, those forwardports
get updated automatically ("followup").
However there is an issue if the udpate causes a conflict in the
followup: the conflict gets silently pushed, and may fairly easily get
merged if it occurs in an area which the CI doesn't cover.
It's unclear what the policy really should be for this issue, and
there is no real way to *block* a pull request at the moment (save by
putting it in error at the mergebot level I guess?), so for now
clearly notify the user on both the modified PR and the followup,
with a comment on both.
We may want to revisit this eventually.
Fixes#467
On edition of an intermediate PR in a chain, merging the PR would lead
to *it* being forward-ported, duplicating the PRs already created
from *its* source.
Add a check for PRs in the target branch with the same source,
suppresses the forward-porting of the newly merged PR.
Fixes#451 (hopefully)
