Fix notebook metadata loss when using remote Jupyter Server kernels

[Copilot]

This PR fixes an issue where language_info metadata was being deleted from notebooks when reopening them with remote Jupyter Server kernels.

Problem

When using a remote Jupyter server (e.g., jupyter notebook --NotebookApp.token='FooBar123'), the following workflow would result in metadata loss:

1. Create and run a notebook with a remote Jupyter server
2. Save the notebook to disk
3. Close and reopen the notebook
4. The notebook shows unsaved changes (circle in tab)
5. When saved, the language_info metadata gets deleted:

-  "language_info": {
-   "codemirror_mode": {
-    "name": "ipython",
-    "version": 3
-   },
-   "file_extension": ".py",
-   "mimetype": "text/x-python",
-   "name": "python",
-   "nbconvert_exporter": "python",
-   "pygments_lexer": "ipython3",
-   "version": "3.10.13"
-  }

Root Cause

The issue was in src/kernels/execution/helpers.ts in the updateNotebookMetadataWithSelectedKernel function. When no local Python interpreter information was available (which is typical for remote kernels), the code would clear the language_info metadata even though it contained valid information from the remote server.

Solution

Modified the logic to preserve existing language_info metadata for remote kernels (startUsingRemoteKernelSpec and connectToLiveRemoteKernel) when no local interpreter information is available. The fix:

• Only clears language_info for local kernels where missing interpreter info might indicate stale data
• Preserves valid language_info from remote servers that was previously saved with the notebook
• Maintains backward compatibility with existing behavior for local kernels

Testing

Added comprehensive test cases covering both remote kernel scenarios:

• RemoteKernelSpecConnectionMetadata without interpreter
• LiveRemoteKernelConnectionMetadata without interpreter

All existing tests continue to pass, ensuring no regressions in local kernel behavior.

Fixes #16207.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• 0.0.0.123
  • Triggering command: node /home/REDACTED/work/vscode-jupyter/vscode-jupyter/node_modules/.bin/mocha --config ./build/.mocha.unittests.js.json ./out/interactive-window/generatedCodeStorageManager.unit.test.js ./out/interactive-window/shiftEnterBanner.unit.test.js ./out/kernels/helpers.unit.test.js ./out/kernels/kernelAutoReConnectMonitor.unit.test.js ./out/kernels/kernelAutoRestartMonitor.unit.test.js ./out/kernels/kernelCrashMonitor.unit.test.js ./out/kernels/kernelDependencyService.unit.test.js ./out/kernels/kernelFinder.unit.test.js ./out/kernels/kernelProvider.node.unit.test.js ./out/kernels/kernelProvider.web.unit.test.js ./out/kernels/kernelRefreshIndicator.node.unit.test.js ./out/kernels/kernelRefreshIndicator.web.unit.test.js ./out/test/package.nls.json.unit.test.js out/kernels/execution/helpers.unit.test.js (packet block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.