Two places checked `if post.tag_categories: return` before doing
a full cache-coverage check, causing posts with partial cache
composes (e.g. 5/40 tags from the background prefetch) to get
stuck at low coverage forever:
ensure_categories: removed the post.tag_categories early exit.
Now ALWAYS runs try_compose_from_cache first. Only the 100%
coverage return (True) is trusted as "done." Partial composes
return False and fall through to the fetch path.
_ensure_post_categories_async: removed the post.tag_categories
guard. Danbooru/e621 are filtered by the client.category_fetcher
is None check instead (they categorize inline, no fetcher).
For Gelbooru-style sites, always schedules ensure_categories
regardless of current post state.
Root cause: the partial-compose fix (try_compose_from_cache
populates tag_categories even when cache coverage is <100%)
conflicted with the early-exit guards that assumed non-empty
tag_categories = fully categorized. Now the only "fully done"
signal is try_compose_from_cache returning True (100% coverage).
pax
1547cbe55a