id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	launchpad_bug
2757	improve deprecation-warning builder	warner		"We have a buildbot builder that runs tests with `PYTHONWARNINGS=default::DeprecationWarning` (you can do the same at home by running `tox -e deprecations`). But unfortunately it's not currently parsing the output for the `DeprecationWarning: ` lines, so to find out if there are any problems, you have to look at the logfile and scan for red stderr messages.

My preferred fix would be for the tox `deprecations` environment to run some shell scripts, to `tee` the logfile into a separate file, `grep` for the warnings, and dump the results in a new `deprecations.log` file. Then the buildbot could add that as a ""logfile"", and flunk the step unless it's empty. Unfortunately it seems that `tox` really wants to encourage cross-platform compatibility, by not running the commands in a shell: I tried `trial allmydata | tee -a log.out` and got a complaint from trial that `|` wasn't a valid test module to run.

We could change this to `make test-deprecations`, which might provoke a tox complaint (since it doesn't remember installing `make`), but might still work. Or we could write some python tooling that installs a command into the virtualenv's `bin/` that does the same thing.

I kind of want `tox` to do this, because then it's easier to run at home. I think I want it to dump the list of deprecations at the end of the test run (unless there are a lot of them, then maybe dumping the count and the name of the file would be enough). It could also exit with rc!=0 if there were any warnings.

If we can't get tox to drive this, we could find a way to change the buildbot to grep stderr (and not just stdout) for the messages. I think it used to do this, but something changed in buildbot in the last few years (maybe related to ""new-style"" build steps, and the emulation code that provides support for old-style ones), and now the regexp is only being given stdout lines, not stderr.
"	task	closed	minor	1.12.0	dev-infrastructure	1.10.2	fixed