A couple of days ago a bunch of demo envs were failing to upload subtitles. Uploads would go through, but text would be empty (timming, number of subs, etc were ok). Could not repro locally, nor on staging, nor on dev. After a very fun debugging session, this is what happens:
- babelsubs requires bleach
- bleach requires an unpinned (latest) version of html5lib
Html5lib released a backwards incompatible release a couple of days ago. So, when creating a new env, pip would find the babelsubs dependency. Then the bleach dependency, then the html5lib, and would install the broken version. Everything 'worked' except bleach.clean would return an empty string instead of anything else.
Therefore, those new envs would get html5lib-1.01a which is broken, but our local installs would still be on 0.95 (which works). This is their bug report: mozilla/bleach#94
The fix (hopefully) is to load our pinned down version of html5lib before bleach so that when pip finds the dependency on bleach it won't need to install anything else, see https://github.com/pculture/babelsubs/commit/e30f9f3e988ab22895050c59faf9fa0c30496b5c