[PR #23868] fix: always rAF-throttle markdown parsing during streaming #27414

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opened 2026-04-20 07:03:34 -05:00 by GiteaMirror · 0 comments
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📋 Pull Request Information

Original PR: https://github.com/open-webui/open-webui/pull/23868
Author: @Algorithm5838
Created: 4/18/2026
Status: 🔄 Open

Base: devHead: fix/markdown-streaming-throttle


📝 Commits (1)

  • c2d675e fix: always rAF-throttle markdown parsing during streaming

📊 Changes

1 file changed (+3 additions, -9 deletions)

View changed files

📝 src/lib/components/chat/Messages/Markdown.svelte (+3 -9)

📄 Description

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Changelog Entry

Description

When "Fade Effect for Streaming Text" is disabled, ResponseMessage passes done={true} to suppress the fade animation in TextToken. Markdown.svelte uses the same prop to decide how to schedule parsing: done === true triggers a synchronous parseTokens() on every content update, bypassing the requestAnimationFrame throttle. So turning the fade off accidentally causes the markdown parser to block the main thread on every streaming chunk.

Fix: always schedule via requestAnimationFrame. The done prop still flows to children unchanged, so animation behavior is unaffected.

Added

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

Changed

  • [List any changes, updates, refactorings, or optimizations]

Deprecated

  • [List any deprecated functionality or features that have been removed]

Removed

  • [List any removed features, files, or functionalities]

Fixed

  • Markdown token parsing no longer runs synchronously on every streaming chunk when the fade effect is disabled

Security

  • [List any new or updated security-related changes, including vulnerability fixes]

Breaking Changes

  • BREAKING CHANGE: [List any breaking changes affecting compatibility or functionality]

Additional Information

  • [Insert any additional context, notes, or explanations for the changes]
    • [Reference any related issues, commits, or other relevant information]

Screenshots or Videos

  • [Attach any relevant screenshots or videos demonstrating the changes]

Contributor License Agreement

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Deleting the CLA section will lead to immediate closure of your PR and it will not be merged in.


🔄 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/open-webui/open-webui/pull/23868 **Author:** [@Algorithm5838](https://github.com/Algorithm5838) **Created:** 4/18/2026 **Status:** 🔄 Open **Base:** `dev` ← **Head:** `fix/markdown-streaming-throttle` --- ### 📝 Commits (1) - [`c2d675e`](https://github.com/open-webui/open-webui/commit/c2d675e6aca85c402c01959661fc5d722d4bb3ff) fix: always rAF-throttle markdown parsing during streaming ### 📊 Changes **1 file changed** (+3 additions, -9 deletions) <details> <summary>View changed files</summary> 📝 `src/lib/components/chat/Messages/Markdown.svelte` (+3 -9) </details> ### 📄 Description <!-- ⚠️ CRITICAL CHECKS FOR CONTRIBUTORS (READ, DON'T DELETE) ⚠️ 1. Target the `dev` branch. PRs targeting `main` will be automatically closed. 2. Do NOT delete the CLA section at the bottom. It is required for the bot to accept your PR. --> # Pull Request Checklist ### Note to first-time contributors: Please open a discussion post in [Discussions](https://github.com/open-webui/open-webui/discussions) to discuss your idea/fix with the community before creating a pull request, and describe your changes before submitting a pull request. This is to ensure large feature PRs are discussed with the community first, before starting work on it. If the community does not want this feature or it is not relevant for Open WebUI as a project, it can be identified in the discussion before working on the feature and submitting the PR. **Before submitting, make sure you've checked the following:** - [x] **Target branch:** Verify that the pull request targets the `dev` branch. **PRs targeting `main` will be immediately closed.** - [x] **Description:** Provide a concise description of the changes made in this pull request down below. - [x] **Changelog:** Ensure a changelog entry following the format of [Keep a Changelog](https://keepachangelog.com/) is added at the bottom of the PR description. - [x] **Documentation:** Add docs in [Open WebUI Docs Repository](https://github.com/open-webui/docs). Document user-facing behavior, environment variables, public APIs/interfaces, or deployment steps. - [x] **Dependencies:** Are there any new or upgraded dependencies? If so, explain why, update the changelog/docs, and include any compatibility notes. Actually run the code/function that uses updated library to ensure it doesn't crash. - [x] **Testing:** Perform manual tests to **verify the implemented fix/feature works as intended AND does not break any other functionality**. Include reproducible steps to demonstrate the issue before the fix. Test edge cases (URL encoding, HTML entities, types). Take this as an opportunity to **make screenshots of the feature/fix and include them in the PR description**. - [x] **Agentic AI Code:** Confirm this Pull Request is **not written by any AI Agent** or has at least **gone through additional human review AND manual testing**. If any AI Agent is the co-author of this PR, it may lead to immediate closure of the PR. - [x] **Code review:** Have you performed a self-review of your code, addressing any coding standard issues and ensuring adherence to the project's coding standards? - [x] **Design & Architecture:** Prefer smart defaults over adding new settings; use local state for ephemeral UI logic. Open a Discussion for major architectural or UX changes. - [x] **Git Hygiene:** Keep PRs atomic (one logical change). Clean up commits and rebase on `dev` to ensure no unrelated commits (e.g. from `main`) are included. Push updates to the existing PR branch instead of closing and reopening. - [x] **Title Prefix:** To clearly categorize this pull request, prefix the pull request title using one of the following: - **BREAKING CHANGE**: Significant changes that may affect compatibility - **build**: Changes that affect the build system or external dependencies - **ci**: Changes to our continuous integration processes or workflows - **chore**: Refactor, cleanup, or other non-functional code changes - **docs**: Documentation update or addition - **feat**: Introduces a new feature or enhancement to the codebase - **fix**: Bug fix or error correction - **i18n**: Internationalization or localization changes - **perf**: Performance improvement - **refactor**: Code restructuring for better maintainability, readability, or scalability - **style**: Changes that do not affect the meaning of the code (white space, formatting, missing semi-colons, etc.) - **test**: Adding missing tests or correcting existing tests - **WIP**: Work in progress, a temporary label for incomplete or ongoing work # Changelog Entry ### Description When "Fade Effect for Streaming Text" is disabled, `ResponseMessage` passes `done={true}` to suppress the fade animation in `TextToken`. `Markdown.svelte` uses the same prop to decide how to schedule parsing: `done === true` triggers a synchronous `parseTokens()` on every content update, bypassing the `requestAnimationFrame` throttle. So turning the fade off accidentally causes the markdown parser to block the main thread on every streaming chunk. Fix: always schedule via `requestAnimationFrame`. The `done` prop still flows to children unchanged, so animation behavior is unaffected. ### Added - [List any new features, functionalities, or additions] ### Changed - [List any changes, updates, refactorings, or optimizations] ### Deprecated - [List any deprecated functionality or features that have been removed] ### Removed - [List any removed features, files, or functionalities] ### Fixed - Markdown token parsing no longer runs synchronously on every streaming chunk when the fade effect is disabled ### Security - [List any new or updated security-related changes, including vulnerability fixes] ### Breaking Changes - **BREAKING CHANGE**: [List any breaking changes affecting compatibility or functionality] --- ### Additional Information - [Insert any additional context, notes, or explanations for the changes] - [Reference any related issues, commits, or other relevant information] ### Screenshots or Videos - [Attach any relevant screenshots or videos demonstrating the changes] ### Contributor License Agreement <!-- 🚨 DO NOT DELETE THE TEXT BELOW 🚨 Keep the "Contributor License Agreement" confirmation text intact. Deleting it will trigger the CLA-Bot to INVALIDATE your PR. Your PR will NOT be reviewed or merged until you check the box below confirming that you have read and agree to the terms of the CLA. --> - [x] By submitting this pull request, I confirm that I have read and fully agree to the [Contributor License Agreement (CLA)](https://github.com/open-webui/open-webui/blob/main/CONTRIBUTOR_LICENSE_AGREEMENT), and I am providing my contributions under its terms. > [!NOTE] > Deleting the CLA section will lead to immediate closure of your PR and it will not be merged in. --- <sub>🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.</sub>
GiteaMirror added the pull-request label 2026-04-20 07:03:34 -05:00
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Reference: github-starred/open-webui#27414