testing: add a utility function to wait for file create This is similar to `tests/testlib/wait-on-file`, but for the python code Differential Revision: https://phab.mercurial-scm.org/D10476

streamclone: check the errors log in tests Code can be buggy, in that case having error message tend to help. Differential Revision: https://phab.mercurial-scm.org/D10475

mail: use a context manager when writing to mbox Differential Revision: https://phab.mercurial-scm.org/D10484

errors: remove unnecessary varargs handling from OutOfBandError In my recent D10465, I moved some code over from scmutil into `OutOfBandError.__init__`. The code was written to deal with an arbitrary number of `message` arguments to the constructor. It turns out that we only ever pass 0 or 1. Given that, let's simplify it. Differential Revision: https://phab.mercurial-scm.org/D10483

phab-refresh: use a special comment on the stable branch Phabricator make it hard to spot the branch information. As a result patch intended for stable are consistently queued for default. We add a special command and flashy GIF to try to attract reviewer attention on the fact patch are intended for stable. Differential Revision: https://phab.mercurial-scm.org/D10464

phab-refresh: extract the comment in a variable This make the script more readable and it is about to become more complex. Differential Revision: https://phab.mercurial-scm.org/D10463

tests: make test-archive.t pass on py3.9 (issue6504) Something got stricter at parsing URL query parameters and now the parameters need to be separated by "&"; ";" is no longer allowed. See issue6504 for details. Differential Revision: https://phab.mercurial-scm.org/D10472

errors: raise RemoteError in some places in exchange.py This is part of https://www.mercurial-scm.org/wiki/ErrorCategoriesPlan Differential Revision: https://phab.mercurial-scm.org/D10467