By mistake, my git repo had symlinked files in it. (A poorly named virtualenv directory had been checked in, it seems.) This causes zip to fail and thus the function to fail. There seems to be a --symlinks option to zip which would make this not fail.
(This isn't particularly important to me since I cleaned up the repo to remove the bad files, but this issue might be useful to someone else who stumbles upon this, and it'd be a convenient thing to not fail on.)
By mistake, my git repo had symlinked files in it. (A poorly named virtualenv directory had been checked in, it seems.) This causes zip to fail and thus the function to fail. There seems to be a --symlinks option to zip which would make this not fail.
(This isn't particularly important to me since I cleaned up the repo to remove the bad files, but this issue might be useful to someone else who stumbles upon this, and it'd be a convenient thing to not fail on.)