fix: prevent mobile auto-scroll feedback loops - #1216
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EdgeDraggingAutoScroller._scroll re-invokes itself via `await _scroll()` while `_scrolling` is true. position.moveTo can complete synchronously when the scrollable cannot advance (already at an extent, zero scroll range, or pinned), turning the self-recursion into a tight microtask loop that pins the platform/UI thread with no frames — an ANR on mobile when leaving a table cell (symbolicated: _microtaskLoop -> Future completion -> EdgeDraggingAutoScroller._scroll). Stop when moveTo makes no forward progress, which bounds the loop.
Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: Cursor <cursoragent@cursor.com>
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Co-authored-by: Cursor <cursoragent@cursor.com>
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Summary
Fixes #1215.
This fixes a mobile editor auto-scroll feedback loop that remained after the table row-height relayout fix in #1214. On a physical Android device, table focus/defocus could still ANR the app; after moving repeat work off microtasks, the remaining issue surfaced as visible content vibration during table selection.
Root cause
EdgeDraggingAutoScroller._scrollrecursively awaited itself while_scrollingwas true.ScrollPosition.moveTocan complete synchronously when the scroll position cannot make meaningful progress, so the recursion can become a tight microtask chain that starves frames/input.Separately, mobile selection changes were starting repeating auto-scroll for ordinary caret/table focus updates. Those updates need at most a one-shot keep-visible nudge; continuous repeat should be reserved for active drag selection.
Fix
SchedulerBinding.scheduleFrameCallbackinstead of recursiveawait _scroll().repeatflag to the auto-scroll service.repeat: trueonly for mobile drag modes (leftSelectionHandle,rightSelectionHandle,cursor); ordinary selection/caret updates use one-shot auto-scroll.Verification
dart format --set-exit-if-changedon touched Dart filesflutter analyzeMade with Cursor