[PR #749] [CLOSED] fix(core): prevent input starvation from high-frequency mouse scroll events #755

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opened 2026-03-02 23:47:58 +03:00 by kerem · 0 comments

kerem commented

2026-03-02 23:47:58 +03:00

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📋 Pull Request Information

Original PR: https://github.com/anomalyco/opentui/pull/749
Author: @androolloyd
Created: 2/27/2026
Status: ❌ Closed

Base: main ← Head: fix/mouse-scroll-flood-input-starvation

📝 Commits (1)

2c83eb5 fix(core): prevent input starvation from high-frequency mouse scroll events

📊 Changes

4 files changed (+133 additions, -30 deletions)

View changed files

📝 packages/core/src/lib/parse.mouse.test.ts (+67 -13)
📝 packages/core/src/lib/parse.mouse.ts (+7 -2)
📝 packages/core/src/renderer.ts (+58 -13)
📝 packages/core/src/testing/integration.test.ts (+1 -2)

📄 Description

Summary

Fixes #748 — high-frequency scroll wheels (Logitech MX Master 3 free-spin) cause keyboard input loss and event loop starvation.

Changes

1. Forward remaining non-mouse data from mixed stdin chunks

stdinListener previously returned early after handleMouseData found any mouse events, silently dropping non-mouse data (keyboard input, focus-in/out sequences) that arrived in the same OS read. Now handleMouseData returns the consumed byte count and stdinListener forwards the remainder to StdinBuffer.

2. Coalesce consecutive scroll events within a chunk

Added coalesceScrollEvents() that merges adjacent same-direction scroll events at the same coordinates into a single event with accumulated delta. This reduces the number of hit tests, MouseEvent constructions, and renderable dispatches from O(n) to O(1) per direction per chunk.

3. Return consumed offset from `parseAllMouseEvents`

Changed parseAllMouseEvents return type from RawMouseEvent[] to { events: RawMouseEvent[], consumed: number } so callers know exactly how many bytes were consumed and can handle the remainder appropriately.

Testing

Updated all existing parseAllMouseEvents tests for new return type
Added 5 new tests for consumed byte tracking (trailing focus sequences, keyboard data, mixed buffers)
Updated integration.test.ts for new return type
All 196 tests pass (mouse parser + stdin buffer + integration)

_{🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.}

## 📋 Pull Request Information **Original PR:** https://github.com/anomalyco/opentui/pull/749 **Author:** [@androolloyd](https://github.com/androolloyd) **Created:** 2/27/2026 **Status:** ❌ Closed **Base:** `main` ← **Head:** `fix/mouse-scroll-flood-input-starvation` --- ### 📝 Commits (1) - [`2c83eb5`](https://github.com/anomalyco/opentui/commit/2c83eb50a892ec600753f1e9a94a135d1cf258ca) fix(core): prevent input starvation from high-frequency mouse scroll events ### 📊 Changes **4 files changed** (+133 additions, -30 deletions) <details> <summary>View changed files</summary> 📝 `packages/core/src/lib/parse.mouse.test.ts` (+67 -13) 📝 `packages/core/src/lib/parse.mouse.ts` (+7 -2) 📝 `packages/core/src/renderer.ts` (+58 -13) 📝 `packages/core/src/testing/integration.test.ts` (+1 -2) </details> ### 📄 Description ## Summary Fixes #748 — high-frequency scroll wheels (Logitech MX Master 3 free-spin) cause keyboard input loss and event loop starvation. ## Changes ### 1. Forward remaining non-mouse data from mixed stdin chunks `stdinListener` previously returned early after `handleMouseData` found any mouse events, silently dropping non-mouse data (keyboard input, focus-in/out sequences) that arrived in the same OS read. Now `handleMouseData` returns the consumed byte count and `stdinListener` forwards the remainder to `StdinBuffer`. ### 2. Coalesce consecutive scroll events within a chunk Added `coalesceScrollEvents()` that merges adjacent same-direction scroll events at the same coordinates into a single event with accumulated `delta`. This reduces the number of hit tests, MouseEvent constructions, and renderable dispatches from O(n) to O(1) per direction per chunk. ### 3. Return consumed offset from `parseAllMouseEvents` Changed `parseAllMouseEvents` return type from `RawMouseEvent[]` to `{ events: RawMouseEvent[], consumed: number }` so callers know exactly how many bytes were consumed and can handle the remainder appropriately. ## Testing - Updated all existing `parseAllMouseEvents` tests for new return type - Added 5 new tests for consumed byte tracking (trailing focus sequences, keyboard data, mixed buffers) - Updated `integration.test.ts` for new return type - All 196 tests pass (mouse parser + stdin buffer + integration) --- <sub>🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.</sub>