Parsing coverage from a push containing a coverage-enabled source-test task fails

[marco-c]

Parsing coverage from cfeddbeafb47a71ca48f913147e71610c9e58c70 is failing https://firefox-ci-tc.services.mozilla.com/tasks/ZkRLlqy4TomIdwHl8vkK_Q/runs/0/logs/public/logs/live.log:

2022-01-25 15:24:44.937856 [INFO    ] code_coverage_bot.hooks.base: Local storage initialized. (artifacts='/build/ccov-artifacts' reports='/build/ccov-reports')
2022-01-25 15:24:44.946248 [INFO    ] code_coverage_bot.hooks.base: Mercurial setup (repository='https://hg.mozilla.org/try' revision='cfeddbeafb47a71ca48f913147e71610c9e58c70')
2022-01-25 15:24:45.284650 [INFO    ] code_coverage_bot.hgmo: Configured HGMO server (address='https://hg.mozilla.org/try' dir=None)
2022-01-25 15:24:51.916144 [INFO    ] code_coverage_bot.artifacts: Downloading artifacts from 1 tasks
2022-01-25 15:24:51.918361 [ERROR   ] code_coverage_bot.hooks.base: Exception while downloading coverage artifacts or cloning repository (exception=TypeError("argument of type 'NoneType' is not iterable"))
Traceback (most recent call last):
  File "/usr/local/lib/python3.9/site-packages/code_coverage_bot/hooks/base.py", line 124, in retrieve_source_and_artifacts
    logger.error(format_exception(exc, exc, exc.__traceback__))
  File "/usr/local/lib/python3.9/site-packages/structlog/stdlib.py", line 164, in error
    return self._proxy_to_logger("error", event, *args, **kw)
  File "/usr/local/lib/python3.9/site-packages/structlog/stdlib.py", line 213, in _proxy_to_logger
    return super()._proxy_to_logger(method_name, event=event, **event_kw)
  File "/usr/local/lib/python3.9/site-packages/structlog/_base.py", line 203, in _proxy_to_logger
    args, kw = self._process_event(method_name, event, event_kw)
  File "/usr/local/lib/python3.9/site-packages/structlog/_base.py", line 171, in _process_event
    raise ValueError(
ValueError: Last processor didn't return an appropriate value.  Valid return values are a dict, a tuple of (args, kwargs), bytes, or a str.

The task we are failing to parse is https://firefox-ci-tc.services.mozilla.com/tasks/JWSwQvELR6C6U2mz66BCfA.
The problem is that we can't retreive suite and chunk name from the task definition.