Fails to generate log file for firefox

trying gource against the firefox code base https://github.com/mozilla-firefox/firefox

it is a very large git repo (4.1 gig, 908k commits, first commit 1998)

The reported error is

gource: failed to generate log file

this comment suggests that gource can fail on funky git entries https://github.com/acaudwell/Gource/issues/100#issuecomment-577775162

trying to identify the specific issue