Threadline for VS Code

Review Python methods with their original code, calls, effects, tests, callers, and models together inside VS Code. Threadline reads source without importing or executing the project, installing its dependencies, or sending its source to a service.

This is a desktop extension preview, distributed as a VSIX. It is not yet listed on the Visual Studio Marketplace. It requires VS Code 1.95+ and Python 3.12+; Git is needed only for change reviews. The analyzer is bundled with the extension.

Install

In VS Code, run Extensions: Install from VSIX… and select threadline-review-0.1.0.vsix. Reload if prompted, then open a trusted project folder.

If Python cannot be found, the error offers Choose Python…, or run Threadline: Choose Python Interpreter… at any time. It checks the version and stores the path in the Threadline: Python Path user setting. This is an executable path, not a shell command; arguments and environment activation commands are not supported.

Review

Click the Threadline button in the editor title bar, available on every file, or right-click → Threadline: Open Review. In a Python file it saves the file and selects the function at the cursor. Anywhere else, or outside a function, it opens the workspace review. While a review is open, it reuses the panel without indexing again. Select a project call, related test, or caller to read it beside the selected method; Open → follows it within the review. Open in editor jumps to source.

The Command Palette also provides:

The status bar shows whether the open review is current, refreshing, stale, or waiting on unsaved edits; click it to show or refresh the review. Saving a Python file, or a Python file changing on disk, refreshes the review automatically. Set threadline.refreshOnSave to false to refresh manually. Other files never mark the review stale. Unsaved buffers are not analyzed. A source jump opens the current file only when its bytes match the evidence; otherwise it opens a read-only threadline-source: document containing the preserved snapshot. Closing the review stops its analyzer. Only one workspace review is open at a time. In a multi-root workspace, the active file determines the folder, or a folder picker appears.

The HTML export contains reviewed source, including baseline source when requested. It works offline and needs neither VS Code nor Python to view.

Scope and configuration

• threadline.pythonPath: trusted Python executable, configured at machine/user level.
• threadline.sourceRoots: optional paths relative to the workspace folder, such as ["src", "tests"].
• threadline.exclude: additional relative paths/globs to exclude from analysis.
• threadline.refreshOnSave: refresh the open review after Python files are saved (default true).

Changing the first three offers Reopen Review to apply them. Narrow the source roots for large repositories. Analysis requests time out after three minutes; HTML exports after four minutes. Query responses are capped at 16 MiB. Old snapshots are retained for the current review within the analyzer's four-snapshot limit.

Analysis is static: dynamic dispatch can remain possible or unknown, and linked tests are not executed. This preview does not support vscode.dev, github.dev, or virtual workspaces. Remote extension hosts require Python and Git on that host; remote environments and Windows/macOS have not yet been validated for this preview.

Build and test

From this directory, with Node.js 20+ and Python 3.12+ installed:

npm ci --ignore-scripts
npm run compile
npm test
npm run package

The package is written to dist/threadline-review-0.1.0.vsix. npm test launches an isolated VS Code extension development host and tests real webview loading, cursor selection, source jumps, dirty buffers, refresh, Git baselines, export, and process cleanup. It downloads a test VS Code unless VSCODE_EXECUTABLE points to an existing application executable. Set THREADLINE_TEST_PYTHON to choose the test interpreter. On headless Linux, use xvfb-run -a npm test.

From the repository root, python -m unittest test_vscode_bridge -v tests the isolated Python transport, including rejection of arbitrary source paths, snapshot retention, and preservation of the old review after a failed refresh. Build assets copy the shared analyzer and review UI; generated files are not committed. No separately installed Threadline package is needed.