Bryan Chen

This commit **updates the documentation** for the **AI's `fix-error` skill and prompt**, introducing a new analytical strategy for error resolution. Instead of relying on hardcoded knowledge, the AI is now instructed to analyze the **error construction code** directly within the codebase. This approach enables the AI to dynamically understand error conditions, categories, and thresholds by reading the surrounding code, as exemplified by the `ListenerLeakError` classification in `event.ts`. This enhancement aims to improve the **accuracy and adaptability of AI-generated fixes** by providing a more context-aware understanding of error origins.

This commit introduces a **bug fix** and improves **error handling** within the **Chat Editing** feature, specifically addressing issues related to **notebook snapshots**. It implements a mechanism in `src/vs/workbench/contrib/chat/browser/chatEditing/chatEditingModifiedNotebookEntry.ts` to gracefully **catch errors** that occur when notebook snapshots become excessively large. Instead of causing failures, these errors are now logged, providing a **fallback** for diagnostic purposes. This ensures a more stable and resilient user experience when interacting with large notebooks within the chat interface.

This commit **enhances the draft Pull Request guidelines** for error handling and validation by updating the `.github/prompts/fix-error.prompt.md` file. It introduces more detailed sections covering PR summaries, issue linking, trigger scenarios, code flow diagrams, and manual validation steps, alongside clarifying PR monitoring instructions. This **documentation enhancement** aims to improve the quality and comprehensiveness of PR submissions, ultimately leading to more efficient code reviews and better-understood fixes for the **developer workflow**.

This commit introduces a **refactoring** within the **Chat editing feature** to improve code maintainability and reduce redundancy. It **extracts a new private helper method**, `_safeCreateSnapshot`, into `src/vs/workbench/contrib/chat/browser/chatEditing/chatEditingModifiedNotebookEntry.ts`. This helper centralizes and **deduplicates error handling logic** for snapshot creation, ensuring a consistent approach when generating snapshots. The change simplifies existing methods like `getCurrentSnapshot` and `createSnapshot`, making the snapshot process more robust and easier to maintain.

This commit introduces a **bug fix** to enhance the stability of the **chat editing feature** when dealing with large notebooks. Previously, `NotebookTextModel.createSnapshot()` could silently strip outputs or throw unhandled errors if a notebook exceeded the backup size limit. Now, the **notebook core model** (`notebookTextModel.ts`) is updated to explicitly **throw an error** in such cases. The **chat editing component** (`chatEditingModifiedNotebookEntry.ts`) is modified to **catch these snapshot creation errors**, log them appropriately (without sensitive URIs), and gracefully **fall back to the notebook's initial content**. This prevents unhandled exceptions and ensures a more robust user experience within **chat editing**.

This commit **improves error handling** within the **chat editing subsystem** by catching exceptions that occur during notebook snapshot creation. Specifically, it addresses cases where `NotebookTextModel.createSnapshot()` might fail (e.g., due to large notebook outputs), preventing unhandled propagation. The **bug fix** ensures that methods like `getCurrentSnapshot()` and `createSnapshot()` in `chatEditingModifiedNotebookEntry.ts` now **log these errors** via the `loggingService` and **fall back to the initial content**, preventing crashes and ensuring robust session persistence. Additionally, it **removes telemetry service usage** related to these specific snapshot errors.

This commit introduces a **robustness fix** for the **Chat Editing** feature by gracefully handling errors during **notebook snapshot creation**. Previously, large notebooks could cause `NotebookTextModel.createSnapshot()` to fail, leading to unhandled exceptions and potential crashes in chat editing sessions. Now, the `chatEditingModifiedNotebookEntry` module **catches these snapshot errors**, logs a `chatEditing/notebookSnapshotError` **telemetry event**, and falls back to initial content or a `Save` context to ensure **session persistence** and prevent crashes. This change also involves a **refactoring** of the snapshot utility to centralize error handling at the caller side, improving the stability of **chat editing with modified notebooks**.

This commit introduces **robust error handling** within the **Chat editing feature** to prevent failures when creating snapshots of modified notebooks that exceed backup size limits. Specifically, it **fixes** an issue where `NotebookTextModel.createSnapshot()` could throw an unhandled 'Notebook too large to backup' error. The `chatEditingModifiedNotebookSnapshot.ts` module now catches this error and retries snapshot creation with `transientOutputs: true` to produce a degraded snapshot without outputs, while `chatEditingModifiedNotebookEntry.ts` falls back to a 'Save' context for initial model setup if the 'Backup' context fails. This ensures a more stable user experience by preventing crashes and allowing continued interaction with large notebooks in Chat, even if a full backup snapshot isn't feasible.

This commit introduces a **fix** to the **notebook backup mechanism**, preventing complete backup failures when notebook outputs exceed a predefined size limit. Instead of throwing an error, the `snapshot` method in `notebookTextModel.ts` now **strips large outputs** from the backup, ensuring a valid, albeit degraded, snapshot is always created. This resolves previously unhandled errors in the **hot-exit backup tracker** and **chat editing snapshot system**, which often led to no backup being saved. Consequently, this **enhances data preservation robustness** for notebooks, guaranteeing that cell source code and metadata are always backed up, even if extensive outputs are omitted.

This commit delivers a crucial **bug fix** for the **Copilot extension**, specifically addressing an unhandled `FileSystemError` that could occur within the `McpLinkedResourceToolResult.render()` method. Previously, the **tool calling UI** could crash or encounter unhandled exceptions when attempting to display linked resources if the associated file was not found or other file system issues arose. The change introduces robust error handling in `extensions/copilot/src/extension/prompts/node/panel/toolCalling.tsx`, differentiating between `FileNotFound` errors and other exceptions, and now gracefully informs the model when a resource is unavailable. This significantly improves the stability and user experience of the **tool calling** feature by preventing crashes related to missing or inaccessible linked files.

This commit implements a **bug fix** within the **Chat Service** by ensuring the `getSession` method explicitly returns `undefined` when a session provider is not found. This change improves **type correctness** and **clarity** for the **Chat feature**, preventing potential runtime errors or unexpected states when a provider is unavailable. Corresponding **tests** in `chatService.test.ts` have been updated to verify this behavior, ensuring robust handling of missing session providers.

This commit performs **maintenance** by updating the **documentation** for the `fix-error` prompt. It adds crucial guidelines for **Pull Request (PR) creation** and details the **Copilot review process** within the `.github/prompts/fix-error.prompt.md` file. This update aims to provide clearer instructions for contributors or automated systems interacting with error fixes, ensuring a smoother workflow and better adherence to project standards for **PRs** and **code reviews**.

This commit introduces a **regression test** within the **Chat service** to validate its session management logic. Specifically, it adds a test case to `src/vs/workbench/contrib/chat/test/common/chatService/chatService.test.ts` that asserts the `acquireOrLoadSession` method returns `undefined` when a remote session provider is not registered. This **maintenance** work ensures the **Chat session acquisition** mechanism behaves correctly under edge conditions, preventing potential issues related to unhandled missing providers. This improves the robustness of the **Chat feature** and directly addresses issue #301203.

This commit performs **maintenance refactoring** within the **Chat Service** to **optimize session loading**. It reorders the logic in the `loadRemoteSession` function within `src/vs/workbench/contrib/chat/common/chatService/chatServiceImpl.ts` to prioritize checking for an existing cached session before attempting provider resolution. This change **improves efficiency** by preventing unnecessary work when a session is already available in the cache. The primary impact is a more responsive and potentially faster startup experience for chat sessions, particularly for remote sessions that can leverage caching.

This commit introduces a **bug fix** to the **Chat service**'s session management within the workbench. Specifically, the `loadRemoteSession` function in `src/vs/workbench/contrib/chat/common/chatService/chatServiceImpl.ts` now includes an early check. It will **return `undefined` immediately** if a required chat session provider cannot be resolved, preventing further execution with an invalid state. This change enhances the **robustness** of the chat feature by gracefully handling missing session providers and avoiding potential runtime errors or unexpected behavior in downstream components.

This commit delivers a crucial **bug fix** to mitigate a **listener leak** within the **Chat feature**, specifically targeting "per-part show-checkmarks subscriptions". It modifies several **chat content parts**, including `chatMarkdownContentPart.ts`, `chatTerminalToolProgressPart.ts`, and `chatToolProgressPart.ts`, as well as the `chatListRenderer.ts`, to ensure proper subscription management and disposal. This change directly addresses potential **memory consumption** issues, enhancing the long-term stability and performance of the chat widget. Minor adjustments to `chat.css` and an error prompt were also included, likely for related visual consistency and improved diagnostics.

This commit **fixes and clarifies the developer documentation** regarding the process for handling **Copilot review comments** in Pull Requests. Specifically, it updates the instructions within `.github/prompts/fix-error.prompt.md` to explicitly guide developers to apply fixes in new commits, resolve comment threads, and monitor the status after each push. This **documentation update** serves as a **process improvement**, aiming to standardize and streamline the workflow for integrating Copilot's feedback, thereby enhancing the overall **PR review and merge efficiency**.

This commit implements a **bug fix and performance optimization** for the **Chat UI rendering** by **refactoring** how `show-checkmarks` are displayed. It moves the class toggling logic and its associated configuration subscription from individual chat content parts, such as tool invocations and code blocks, to the parent row container within `src/vs/workbench/contrib/chat/browser/widget/chatListRenderer.ts`. This change **significantly reduces the accumulation of `onDidChangeConfiguration` listeners**, replacing numerous per-part subscriptions with a single subscription per rendered chat element. Consequently, the **Chat UI** will experience **improved stability and reduced resource consumption**, particularly in sessions with many tool invocations, by preventing potential **listener leaks**. A corresponding CSS adjustment in `src/vs/workbench/contrib/chat/browser/widget/media/chat.css` ensures correct visual presentation.

This commit delivers a crucial **bug fix** and **diagnostic improvement** for the **notebook feature**. It resolves potential "index out of range" errors within the **notebook text model** by correcting a faulty sort comparator found in `src/vs/workbench/contrib/notebook/common/model/notebookTextModel.ts`. Concurrently, the commit enriches the error diagnostics for these index-related problems, providing more informative messages to aid in debugging. This work significantly enhances the **stability and debuggability** of notebooks, ensuring more reliable operation and clearer feedback when model inconsistencies occur.

This commit introduces a **bug fix** to the **telemetry service** specifically for **web environments**, such as Codespaces. It addresses an issue where **error telemetry stack traces** were not being properly preserved, leading to incomplete diagnostic information. The changes in `src/vs/workbench/services/telemetry/browser/telemetryService.ts` implement the necessary logic to ensure these stack traces are now correctly captured. This improvement is validated by updated tests in `src/vs/platform/telemetry/test/browser/telemetryService.test.ts`, significantly enhancing the ability to debug and understand errors originating from web-based instances.