On forward-porting, odoo/odoo#170183 generates a conflict on pretty
much every one of the 1111 files it touches, because they are
modify/delete conflicts that generates a conflict message over 200
bytes per file, which is over 200kB of output.
For this specific scenario, the commit message was being passed
through arguments to the `git` command, resulting in a command line
exceeding `MAX_ARG_STRLEN`[^1]. The obvious way to fix this is to pass
the commit message via stdin as is done literally in the line above
where we just copy a non-generated commit message.
However I don't think hundreds of kbytes worth of stdout[^2] is of any
use, so shorten that a bit, and stderr while at it.
Don't touch the commit message size for now, possibly forever, but
note that some log diving reveals a commit with a legit 18kB message
(odoo/odoo@42a3b704f7) so if we want to
restrict that the limit should be at least 32k, and possibly 64. But
it might be a good idea to make that limit part of the ready / merge
checks too, rather than cut things off or trigger errors during
staging.
Fixes#900
[^1]: Most resources on "Argument list too long" reference `ARG_MAX`,
but on both my machine and the server it is 2097152 (25% of the
default stack), which is ~10x larger than the commit message we
tried to generate. The actual limit is `MAX_ARG_STRLEN` which
can't be queried directly but is essentially hard-coded to
PAGE_SIZE * 32 = 128kiB, which tracks.
[^2]: Somewhat unexpectedly, that's where `git-cherry-pick` sends the
conflict info.
1cea247e6c tried to improve staging
checks to avoid staging PRs in the wrong state, however it had two
issues:
PR state
--------
The process would reset the PR's state to open, but unless the head
was being resync'd it wouldn't re-apply the statuses on the state,
leading to a PR with all-valid statuses, but a missing CI.
Message
-------
The message check didn't compose the PR message the same way PR
creation / update did (it did not trim the title and description
individually, only after concatenation), resulting in a
not-actually-existing divergence getting signaled in the case where
the PR title ends or the description starts with whitespace.
Expand relevant test, add a utility function to compose a PR message
and use it everywhere for coherence.
Also update the logging and reporting to show a diff of all the
updated items (hidden behind a `details` element).
It's a waste to lose the entire staging if it's only a short blip /
delay thing, so retry multiple times. Add utility function to make
backoff functions easier (though the UI is not great ATM).
Also log the "left" parent of a merge commit (which should be the
"base") when creating it, for additional post-mortem information.
Github is subject to a fair amount of transient failures, which are
currently ill-logged: an exception is raised and the caller /
responsible might eventually log something, but it's not really
formalised and centralised, and is thus inconvenient to try and
post-mortem issues with github's support.
Change this such that *almost* all github API calls get extensively
logged (status, reason, all headers, body) on failure.
Also automatically sets debug logging for odoo in local tests, and
alter the fake response constructor thing so it doesn't set a json
mimetype when the body is not valid json.
Closes#98
