bundle: preserve .designer.ipynb suffix when translating notebook task paths

[artchen-db]

Summary

Lakeflow Designer files keep their full .designer.ipynb suffix when imported into the workspace, unlike regular notebooks (.py, .ipynb, .r, .scala, .sql) which lose their extension on import.

translateNotebookPath in bundle/config/mutator/translate_paths.go unconditionally stripped path.Ext(localRelPath). For a foo.designer.ipynb path, path.Ext returns .ipynb, leaving foo.designer — the deployed job's notebook_path then points at a file that does not exist.

Fix

Add notebook.ExtensionDesigner = ".designer.ipynb" and a StripExtension helper in libs/notebook/ext.go that special-cases the designer suffix. Apply it in both branches of translateNotebookPath (the skipLocalFileValidation branch and the post-detection branch).

Reproduction

A bundle with:

resources:
  jobs:
    designer_job:
      tasks:
        - task_key: t
          notebook_task:
            notebook_path: ./foo.designer.ipynb

	Before	After
File in workspace	foo.designer.ipynb (DESIGNER_FILE) ✓	foo.designer.ipynb (DESIGNER_FILE) ✓
Deployed notebook_path	foo.designer → 404 ✗	foo.designer.ipynb ✓

Tests

• libs/notebook/ext_test.go — TestStripExtension covers .py / .ipynb / .r / .scala / .sql, the .designer.ipynb keep-case, and no-extension input.
• bundle/config/mutator/translate_paths_test.go — TestTranslatePathsDesignerNotebook (file present, mixed designer + regular tasks) and TestTranslatePathsDesignerNotebookSkipLocalFileValidation (config-remote-sync branch). Both assert designer suffix is preserved and .py / .ipynb are still stripped.

Out of scope

Other call sites strip path.Ext in the same pattern (libs/sync/snapshot_state.go, bundle/generate/downloader.go, cmd/workspace/workspace/import_dir.go, libs/filer/workspace_files_extensions_client.go). The job-task path covers the reported user-visible bug; whether designer files need the same special-case in sync / generate / import-dir flows depends on whether they round-trip through those paths in a way the workspace API doesn't already handle. Happy to extend in a follow-up if reviewers want.

[github-actions]

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Inputs:

• PR number: 5370
• Commit SHA: d6a03e6e8ceef45d9d19c56cc8a1dd9e3a75ced2

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[github-actions]

Approval status: pending

/bundle/ - needs approval

Files: bundle/config/mutator/translate_paths.go, bundle/config/mutator/translate_paths_test.go
Suggested: @andrewnester
Also eligible: @pietern, @denik, @anton-107, @shreyas-goenka, @janniklasrose, @lennartkats-db

General files (require maintainer)

Files: libs/notebook/ext.go, libs/notebook/ext_test.go
Based on git history:

• @andrewnester -- recent work in bundle/config/mutator/

_{Any maintainer (@andrewnester, @anton-107, @denik, @pietern, @shreyas-goenka, @simonfaltum, @renaudhartert-db) can approve all areas.
See OWNERS for ownership rules.}