Two bugs in handleScroll's loadMoreMessages flow surfaced after the
smooth-scroll race fix.
(1) isLoadingMore stuck across channels. setIsLoadingMore(true) → await
loadMoreMessages → setIsLoadingMore(false) was unguarded. If the user
switched channels during the await, the new channel inherited the flag (same
component instance, same useState slot) and rendered the pagination skeleton
even with no load in flight. Cleared only when the original await resolved
or the component remounted (e.g., navigating to Friends and back).
(2) Wrong-channel scroll restore. The post-await rAF set
container.scrollTop = container.scrollHeight - prevScrollHeight against the
new channel's container with the old channel's prevScrollHeight, yanking
the new channel to a wrong position.
Fix:
- try/finally around the await so setIsLoadingMore(false) always runs.
- currentChannelIdRef tracks the live channelId; capture requestChannelId at
load start and compare both before scheduling the rAF and inside the rAF
callback (the 16ms frame gap is enough for a switch).
- Belt-and-suspenders: setIsLoadingMore(false) in the channel-switch effect
covers the case where the await never resolves (network hang). Without it,
a stuck await would leave the new channel inheriting the flag indefinitely.
No request cancellation — out of scope; AbortController plumbing through
chatStore is a bigger refactor and the channelId guard already silently
drops stale results.
Spec updated. Smooth-scroll fix from the previous commit untouched.
Jannis Braun
8ba644fa44