fix(application): anchor opener route regex for tree paths

[The-Peacemaker]

References

Fixes #7216

Code changes

• Anchor the opener route regex in the application extension so it only matches true notebook/editor routes:
  • from /(notebooks|edit)/(.*)
  • to ^/(notebooks|edit)/(.*)$
• Add a UI regression test in ui-tests/test/tree.spec.ts covering tree navigation/reload when the path contains a directory literally named notebooks.

Problem / root cause

Tree URLs such as /tree/test/notebooks/test were being incorrectly matched by the opener route regex because it was not anchored. That caused the router to treat part of a tree URL as a notebook route and attempt to open a file, leading to File Load Error: Invalid response: 404 Not Found.

Solution

Use an anchored regex so the opener only handles paths that begin with /notebooks/ or /edit/.

User-facing changes

Users can navigate and refresh tree paths containing directories named notebooks without spurious file load errors.

Backwards-incompatible changes

None.

[github-actions]

👈 Launch a Binder on branch The-Peacemaker/notebook/fix-tree-route-notebooks-path-7216

[Copilot]

Pull request overview

This PR fixes incorrect route matching in the application extension by anchoring the opener route regex so /tree/.../notebooks/... paths are no longer treated as notebook/editor routes, and adds a UI regression test to cover the scenario from #7216.

Changes:

• Anchor the opener route regex to only match full /notebooks/... and /edit/... paths.
• Add a Playwright/Galata UI test to ensure reloading a tree URL containing a directory named notebooks does not surface a “File Load Error”.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
packages/application-extension/src/index.ts	Anchors the route regex used by the opener router handler to prevent substring matches inside /tree/... paths.
ui-tests/test/tree.spec.ts	Adds a regression test for navigating to and reloading a tree path that includes a literal notebooks directory.

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[goelakash]

I reproduced the existing bug locally:

mkdir -p /tmp/jupyter-test/test/notebooks/test
cd /tmp/jupyter-test
jupyter notebook --no-browser --ServerApp.token='' --port=8889

Navigating to http://localhost:8889/tree/test/notebooks/test shows "File Load Error for test" -> the app tries to open test as a notebook file instead of showing the directory listing.

The issue is the unanchored regex:

const TREE_PATTERN = new RegExp('/(notebooks|edit)/(.*)');

This matches /(notebooks|edit)/ anywhere in the URL. So /tree/test/notebooks/test matches the substring /notebooks/test in the middle, and the router thinks you're trying to open a file called test.

The fix anchors it with ^ so only URLs that actually start with /notebooks/ or /edit/ are matched — tree paths with a directory named notebooks are no longer intercepted.

The unit-test also looks like it reproduces to catch the same issue. LGTM (UI test failure looks unrelated).