fix: extract YouTube source URLs from index [2][5]

[MCR-GLOBAL]

Summary

• Fixes Source.url is always None for YouTube sources in list() and from_api_response() #265: Source.url is always None for YouTube sources
• YouTube sources store URL data at src[2][5] as [url, video_id, channel_name] while src[2][7] is null
• Adds YouTube URL fallback ([2][5]) in all three extraction paths: SourcesAPI.list(), and both nested formats in Source.from_api_response()

Test plan

• New unit test: test_from_api_response_youtube_source_url_at_index5 — verifies deeply nested YouTube URL extraction
• New integration test: test_list_sources_youtube_url_at_index5 — verifies list() extracts YouTube URL from src[2][5]
• Existing YouTube tests still pass (URL at [7] path unchanged)
• Full test suite: 2015 passed, 9 skipped

🤖 Generated with Claude Code

Summary by CodeRabbit

• Bug Fixes
  • Improved source URL extraction to reliably detect and parse URLs from YouTube, web, PDF, and other source types
  • Enhanced handling of multiple API response data structures with intelligent fallback mechanisms for consistent URL retrieval
  • Strengthened URL detection logic to support various source format variations

[coderabbitai]

📝 Walkthrough

Walkthrough

This PR fixes YouTube source URL extraction in the NotebookLM API client by implementing multi-location fallback logic. The changes add checks for YouTube URLs at src[2][5][0] alongside existing checks at src[2][7][0] and src[2][0] in both the list() and from_api_response() methods, resolving an issue where YouTube source URLs were always None.

Changes

Cohort / File(s)	Summary
URL Extraction Logic src/notebooklm/_sources.py, src/notebooklm/types.py	Implemented multi-fallback URL extraction: attempts src[2][7][0] (web/PDF), then src[2][5][0] (YouTube), then src[2][0] (direct HTTP). Applied consistently across list() and from_api_response() methods in both shallow and deep-nested code paths.
Test Coverage tests/integration/test_sources.py, tests/unit/test_types.py	Added integration and unit tests verifying YouTube URL extraction from the src[2][5][0] position, ensuring the fallback logic correctly populates Source.url for YouTube sources.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

🐰 Through nested indices hopped a determined hare,
YouTube URLs hiding at index five, there!
With fallback logic crafted with care,
Now sources list bright, beyond compare,
A rabbit's fix, both tested and fair! 🎬

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'fix: extract YouTube source URLs from index [2][5]' directly and accurately summarizes the main change: fixing URL extraction for YouTube sources by checking the [2][5] index.
Linked Issues check	✅ Passed	All coding objectives from issue #265 are met: YouTube URL fallback added to src[2][5] in SourcesAPI.list() [283], Source.from_api_response() both nested paths [283], with comprehensive test coverage for both paths validating the fix.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to issue #265: three code paths updated for YouTube URL extraction and two test cases added to validate the fix; no unrelated modifications present.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[gemini-code-assist]

Code Review

This pull request updates the URL extraction logic for sources to accommodate different API response structures, specifically adding support for YouTube URLs and a fallback for HTTP links. Corresponding unit and integration tests have been included to verify the new extraction paths. I have no feedback to provide as there were no review comments to evaluate.

[coderabbitai]

🧹 Nitpick comments (1)

tests/unit/test_types.py (1)

164-198: Add a medium-nested companion case for the same src[2][5] fallback.

This test covers the deeply nested branch well; adding one medium-nested case would guard both parsing branches in Source.from_api_response() against future regressions.

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@tests/unit/test_types.py` around lines 164 - 198, Add a medium-nested
companion test for the same src[2][5] fallback: create a new test (e.g.,
test_from_api_response_youtube_source_url_at_index5_medium_nesting) that builds
a slightly different nesting shape which still places the YouTube tuple at index
[2][5] of the source payload, call Source.from_api_response(...) and assert
source.id == "src_yt2", source.url ==
"https://www.youtube.com/watch?v=dcWU-qD8ISQ" and source.kind ==
SourceType.YOUTUBE; this ensures Source.from_api_response handles both the deep
and medium nesting branches.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@tests/unit/test_types.py`:
- Around line 164-198: Add a medium-nested companion test for the same src[2][5]
fallback: create a new test (e.g.,
test_from_api_response_youtube_source_url_at_index5_medium_nesting) that builds
a slightly different nesting shape which still places the YouTube tuple at index
[2][5] of the source payload, call Source.from_api_response(...) and assert
source.id == "src_yt2", source.url ==
"https://www.youtube.com/watch?v=dcWU-qD8ISQ" and source.kind ==
SourceType.YOUTUBE; this ensures Source.from_api_response handles both the deep
and medium nesting branches.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 727bebb4-3f02-46c4-b779-1e6f46fdace3

📥 Commits

Reviewing files that changed from the base of the PR and between a997718 and 2f9cc7c.

📒 Files selected for processing (4)

• src/notebooklm/_sources.py
• src/notebooklm/types.py
• tests/integration/test_sources.py
• tests/unit/test_types.py