Keyboard scrolling of the message pane (PageUp/PageDown, Arrow keys, Space,
Home/End) fires a native scroll event with no wheel/touch/scrollbar/non-message
intent. Inside the 1400ms post-render artifact window the suppression branch
then returned before movedUp could unpin, so a keyboard scroll-up was swallowed
and live-follow snapped the reader back to the bottom.
- Add _lastMessageKeyScrollIntentMs + _recentMessageKeyScrollIntent(), stamped
by a capture-phase keydown listener on the scroll keys, gated to when the
message pane is the scroll target (focused/contains focus/hovered) and not an
editable field (composer/input/contenteditable).
- Gate the post-render suppression on !_recentMessageKeyScrollIntent() (typeof
guard keeps the #4295 node harness inert).
- Clear the stamp in both _resetScrollDirectionTracker() and
_resetStreamScrollFollow() (same stale-state hygiene as the wheel stamp).
Tests: keyboard-scroll-inside-window-still-unpins behavioral regression (harness
extended with injected _recentMessageKeyScrollIntent), plus a source lock for the
helper/keydown-stamp/suppression-gate/both-resets. test_4856 + test_4295 green
(19 passed), node --check clean.
allenliang2022
6825bc03b4
