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perf: use rAF to debounce getContents() during streaming#22111

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tjbck merged 1 commit intoopen-webui:devfrom
Algorithm5838:perf/debounce-get-contents
Mar 1, 2026
Merged

perf: use rAF to debounce getContents() during streaming#22111
tjbck merged 1 commit intoopen-webui:devfrom
Algorithm5838:perf/debounce-get-contents

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    • docs: Documentation update or addition
    • feat: Introduces a new feature or enhancement to the codebase
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Changelog Entry

Description

getContents() traverses the message tree and regex-scans all assistant content for code/HTML/CSS/JS blocks on every streaming token via $: if (history). On fast models this means dozens of scans per frame with no visual benefit, since the browser only renders at ~60fps. The fix wraps the call in requestAnimationFrame, matching the existing scrollRAF pattern in this file and pendingRebuild in Messages.svelte. The artifact preview continues to update in real time.

Added

  • [List any new features, functionalities, or additions]

Changed

  • Chat.svelte: debounce getContents() with requestAnimationFrame

Deprecated

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⚠️ Warning: Possible Non-Atomic / Scope Creep PR Detected

Your PR was subjected to automated review by AI to determine if it could fall under Open WebUI's non-atomicity ruleset or scope creep.

This PR appears to contain multiple unrelated changes that could be split into separate pull requests.

🔍 AI Analysis Summary

Primary Intent: Performance optimization: debounce getContents() calls using requestAnimationFrame to prevent excessive re-renders when history changes rapidly

Secondary Changes Detected:

  • None identified
📝 Detailed Analysis and Full Report (click to expand)

This diff makes a pure performance optimization to existing code in Chat.svelte. The change adds requestAnimationFrame-based debouncing to the reactive statement that calls getContents() when history changes. This is a classic example of a 'Pre-factor' optimization that could have been merged as a separate PR BEFORE or AFTER any feature work. The optimization is completely independent of any feature - it's merely improving the performance of an already-existing reactive behavior. According to the rejection criteria: 'Bundled Perf: Implementing a feature AND optimizing performance (unless the feature IS the optimization)' - this is NOT the feature being built, it's optimization of existing code. This should have been a separate PR.

Why Atomic PRs With Narrow Scopes Matter

Atomic PRs (single-purpose PRs) are:

  • Easier to review - Reviewers can focus on one thing at a time
  • Easier to test - Each change can be verified independently
  • Easier to revert - If something breaks, we can revert just the problematic change
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What Makes a PR Atomic / Narrow in Scope?

An atomic PR should contain one semantic change:

  • ✅ Just one bug fix (even if it touches multiple files)
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  • ✅ Just i18n/translation updates
  • ✅ Just documentation updates
  • ✅ Just refactoring of one specific thing
  • ✅ Just one performance improvement

What To Do

This is an automated analysis. If you believe this assessment is incorrect and your PR is actually atomic (all changes serve one unified purpose), please explain in a comment below.

Consider splitting this PR into separate, focused pull requests. Each PR should address one specific thing.

For example, if you have a bug fix and a new feature, submit them as two separate PRs.

@Algorithm5838
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This is a single standalone perf fix with no bundled feature work.

@tjbck
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tjbck commented Mar 1, 2026

Thanks!

@tjbck tjbck merged commit 860a0b4 into open-webui:dev Mar 1, 2026
2 checks passed
Classic298 added a commit to Classic298/open-webui that referenced this pull request Mar 1, 2026
@Algorithm5838 Algorithm5838 deleted the perf/debounce-get-contents branch March 1, 2026 22:44
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3 participants