Interacting with the Merge Bot

There is a bot that hangs around on the Syncthing Github projects and assists with doing correct merges of pull requests. Using the merge bot to accept pull requests is the recommended way in all cases as it enforces some extra checks that the “standard” Github merge button does not. The merge bot is currently called st-review.

Merging a PR

There are two ways to merge a pull request - by direct merge command and by lgtm consensus.

You should restrict messages addressed to @st-review to the described commands and avoid mixing them with general purpose conversation - this might cause unexpected side effects.

By “lgtm”

Any developer with push access can evaluate the pull request and let the bot know that they approve of it. The word for this is LGTM, “looks good to me”:

@st-review lgtm

The bot will record the fact that you think so by adding a LGTM: calmh footer to the commit message when it gets merged. The pull request is merged once two developers have given their LGTM’s.

../_images/lgtm.png

The lgtm is hence a way to say “I think this is fine and should be merged, but I’d appreciate a second look from someone else.”

If the commit message or subject needs to be tweaked, used the merge command instead. A previously given lgtm will still be recorded on the commit message.

By “merge”

To merge a pull request, simply tell the bot to do so, making sure that the first word of the command is merge:

@st-review merge
../_images/merge-1.png

It’s also possible to override the resulting commit subject and message when doing this. Just add a blank line, the commit subject, another blank line, and then the commit body (which can be empty). Don’t worry about the text formatting - the commit body will be reflowed appropriately by the bot:

@st-review merge

lib/dialer: Add env var to disable proxy fallback (fixes #3006)
../_images/merge-2.png

Handling Check Results

The merge bot will wait for status checks to resolve, but will refuse to merge pull requests with unclean statuses:

../_images/merge-3.png

It is possible to override this in cases where it’s necessary, by adding a Skip-check command to the commit message body. Note that this must be in the commit message body, which means that you need to supply both a commit message subject and body. Don’t overuse this – it’s better to ask Jenkins to retest if something spurious happened. It can be used to allow merge of commits from unregistered authors that only touches comments, for example.

The tag must be exactly Skip-check: followed by a space separated list of check “contexts” as seen in the list on Github. I.e., to skip these two checks:

../_images/merge-4-0.png

Use the following syntax:

@st-review merge this please

all: Correct spelling in comments

Skip-check: authors pr-build-mac
../_images/merge-4-1.png

Please note that the exact string Skip-check: authors is magic in that it also allows the build to pass, when it would otherwise stop with commits from unknown authors.

Note

If you want to skip the author check, make sure it’s mentioned first and that the string is exactly “Skip-check: authors”.