[PR #21492] fix: UI freeze loading chats on sidebar scroll-down #26102

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GiteaMirror · 2026-04-20T06:19:41-05:00

GiteaMirror commented

2026-04-20 06:19:41 -05:00

📋 Pull Request Information

Original PR: https://github.com/open-webui/open-webui/pull/21492
Author: @Ithanil
Created: 2/16/2026
Status: 🔄 Open

Base: dev ← Head: fix_scrolling_freeze

📝 Commits (1)

8ba272b fix UI freeze loading chats on sidebar scroll-down

📊 Changes

1 file changed (+20 additions, -8 deletions)

View changed files

📝 src/lib/components/layout/Sidebar.svelte (+20 -8)

📄 Description

Pull Request Checklist

Note to first-time contributors: Please open a discussion post in 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:

Target branch: Verify that the pull request targets the dev branch. PRs targeting main will be immediately closed.
Description: Provide a concise description of the changes made in this pull request down below.
Changelog: Ensure a changelog entry following the format of Keep a Changelog is added at the bottom of the PR description.
Documentation: Add docs in Open WebUI Docs Repository. Document user-facing behavior, environment variables, public APIs/interfaces, or deployment steps.
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.
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.
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.
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?
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.
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.
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

This PR fixes a chat-sidebar infinite-scroll failure where reaching the end of history could leave the UI stuck on Loading... and throw:

Uncaught TypeError: can't access property "prev", b is undefined

At the same time, the backend sees never-ending requests to api/v1/chats/?page=N, where N would constantly increase with increment 2.

Root Cause

Sidebar pagination could keep requesting more pages without terminating. Potentially this only happens when certain problematic chats are present in the history.

What Changed

Updated pagination logic in Sidebar.svelte:
Added early return guard when already loading or fully loaded.
Used an explicit nextPage value for fetch consistency.
Filtered out invalid chat rows (missing id).
Deduplicated fetched chats against existing chat IDs before appending.
Marked allChatsLoaded = true when no new unique chats are returned.
Wrapped load flow in try/finally so chatListLoading always resets.

Testing Notes

Scroll chat list to end with a large history.
Verify requests stop once no new unique chats are returned.
Verify no persistent Loading... state and no each.js ... prev crash.

Not Included (Intentional)

A possible hardening change in Loader.svelte was considered: ensuring only one visible dispatch interval runs at a time.
This was not included to keep the fix minimal and focused on the confirmed sidebar pagination issue.

Additional Information

I'm not sure if this here is the optimal fix, but it definitely works.

Screenshots or Videos

Contributor License Agreement

By submitting this pull request, I confirm that I have read and fully agree to the Contributor License Agreement (CLA), 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.

_{🔄 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/21492 **Author:** [@Ithanil](https://github.com/Ithanil) **Created:** 2/16/2026 **Status:** 🔄 Open **Base:** `dev` ← **Head:** `fix_scrolling_freeze` --- ### 📝 Commits (1) - [`8ba272b`](https://github.com/open-webui/open-webui/commit/8ba272beb64ce2dad7a21002d0b2701c5ea9c2e4) fix UI freeze loading chats on sidebar scroll-down ### 📊 Changes **1 file changed** (+20 additions, -8 deletions) <details> <summary>View changed files</summary> 📝 `src/lib/components/layout/Sidebar.svelte` (+20 -8) </details> ### 📄 Description  # 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 This PR fixes a chat-sidebar infinite-scroll failure where reaching the end of history could leave the UI stuck on _Loading..._ and throw: `Uncaught TypeError: can't access property "prev", b is undefined` At the same time, the backend sees never-ending requests to `api/v1/chats/?page=N`, where N would constantly increase with increment 2. #### Root Cause Sidebar pagination could keep requesting more pages without terminating. Potentially this only happens when certain problematic chats are present in the history. #### What Changed - Updated pagination logic in [Sidebar.svelte](https://file+.vscode-resource.vscode-cdn.net/home/ithanil/.vscode/extensions/openai.chatgpt-0.4.74-linux-x64/webview/#): - Added early return guard when already loading or fully loaded. - Used an explicit nextPage value for fetch consistency. - Filtered out invalid chat rows (missing id). - Deduplicated fetched chats against existing chat IDs before appending. - Marked allChatsLoaded = true when no new unique chats are returned. - Wrapped load flow in try/finally so chatListLoading always resets. #### Testing Notes 1) Scroll chat list to end with a large history. 2) Verify requests stop once no new unique chats are returned. 3) Verify no persistent Loading... state and no each.js ... prev crash. #### Not Included (Intentional) A possible hardening change in [Loader.svelte](https://file+.vscode-resource.vscode-cdn.net/home/ithanil/.vscode/extensions/openai.chatgpt-0.4.74-linux-x64/webview/#) was considered: ensuring only one visible dispatch interval runs at a time. This was not included to keep the fix minimal and focused on the confirmed sidebar pagination issue. ### Additional Information I'm not sure if this here is the optimal fix, but it definitely works. ### Screenshots or Videos <img width="468" height="339" alt="Screenshot From 2026-02-16 16-43-13" src="https://github.com/user-attachments/assets/b29eb423-2d8d-4163-8ed6-27db025bc789" /> ### Contributor License Agreement  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 06:19:41 -05:00

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Reference: github-starred/open-webui#26102