The log file shows:

mozcrash WARNING | Found 17 dump files -- limited to 10!
mozcrash INFO    | Copy/paste: /builds/worker/workspace/breakpad-tools/minidump_stackwalk /tmp/f689d312-62c2-47bc-3494e4b0-eb468cb4.dmp /builds/worker/workspace/build/src/obj-spider/dist/crashreporter-symbols
mozcrash checking /tmp for minidumps...
Traceback (most recent call last):
  File "/builds/worker/workspace/build/src/testing/mozbase/mozcrash/mozcrash/mozcrash.py", line 677, in <module>
    test_name=args.test_name)
  File "/builds/worker/workspace/build/src/testing/mozbase/mozcrash/mozcrash/mozcrash.py", line 101, in check_for_crashes
    for info in crash_info:
  File "/builds/worker/workspace/build/src/testing/mozbase/mozcrash/mozcrash/mozcrash.py", line 260, in __iter__
    rv = self._process_dump_file(path, extra)
  File "/builds/worker/workspace/build/src/testing/mozbase/mozcrash/mozcrash/mozcrash.py", line 323, in _process_dump_file
    if "(crashed)" in line:
TypeError: a bytes-like object is required, not 'str'

Bug 1633039 regressed this by running mozcrash.py with Python3. mozcrash has tests that verify that it works with py3, but it seems we're hitting a situation they do not cover. It may be because the tests are all just for the python code, so none of the tests use actual minidumps.

Specifically what is happening is that Popen.communicate is returning stdout as bytes. (The error message makes it sound backwards, but it's sort of like it's calling in<bytes>("(crashed)", line) because line is bytes.) That is the default thing for Popen.communicate to do, so I'll need to look further to see why something different is expected. In the meantime, I'll check to see if I can pass text=True and not break anything.

Set release status flags based on info from the regressing bug 1633039

Fixed by bug 1642662? See also bug 1649703.