fix(web): honor whitespace settings in pull request diffs

[Bil0000]

PR diffs ignored Hide whitespace changes, so adding a JSX wrapper highlighted unchanged, reindented code as deleted and added.

Honor the saved default and add the same show/hide toggle as the regular diff panel. Use the existing diff library to compare each hunk without whitespace, while keeping the original source text. Review comments use the original patch positions and line types, including for GitLab. Cache each mode separately so toggling and expanding context keep the correct view.

Verified with 42 focused tests, the web typecheck, and targeted lint/format checks. Lint warnings are unchanged from main. Browser checks used the real PR viewer with a local reproduction: stacked/split layouts, 640/1280 px widths, both toggle directions, full-file expansion, and a review draft anchored to the correct old/new lines. Web and desktop share this viewer; no server or mobile behavior changes.

Before and after use the same local fixture with the setting enabled.

Model: GPT-6. Harness: Codex.

Summary by CodeRabbit

• New Features

  • Added a pull request diff toolbar option to hide whitespace-only changes.
  • Diff views retain accurate line positions for reviewing and commenting when whitespace changes are hidden.

• Bug Fixes

  • Improved comment placement when viewing filtered diffs.
  • Clearing or changing the whitespace filter resets active draft comments and selected lines to prevent mismatched review context.

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — This changes the existing pull-request diff experience by applying the existing whitespace-hiding default, adding a production toggle, and introducing nontrivial hunk filtering and review-position handling. The default-surface behavior and shared rendering changes warrant human review.

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Dismissing prior approval to re-evaluate e534040

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository: pingdotgg/t3code/.coderabbit.yaml

Review profile: CHILL

Plan: Advanced

Run ID: 21dc2e9c-8eb4-4f4b-be1f-e4de0cbd5daa

📥 Commits

Reviewing files that changed from the base of the PR and between e534040 and edfd247.

📒 Files selected for processing (1)

• apps/web/src/lib/diffRendering.test.ts

Included review availability: Your plan provides up to 10 included reviews per hour; 9 remain after this review.

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📝 Walkthrough

Walkthrough

The pull request adds client-side whitespace filtering to rendered pull request diffs. It adds a code-tab toggle, preserves source files for review-position mapping, updates patch counts and offsets, and adds coverage for filtering, line positions, cache keys, and blank lines.

Changes

Whitespace-Aware Diff View

Layer / File(s)	Summary
Whitespace filtering in patch rendering apps/web/src/lib/diffRendering.ts	getRenderablePatch accepts ignoreWhitespace, filters whitespace-only changes, updates hunk metadata and cache keys, and returns the untransformed sourceFiles.
Code tab whitespace toggle apps/web/src/components/pullRequest/PullRequestCodeTab.tsx	The code tab initializes and passes the whitespace setting, adds a toolbar toggle, clears draft comment state and line selections, and resolves comment positions against matching source files.
Whitespace rendering and position tests apps/web/src/lib/diffRendering.test.ts	Tests cover filtered changes, preserved real changes, diff statistics, cache separation, review positions, hydration, hunk offsets, and blank lines without final newlines.

Priority: ➖ Normal

Estimated code review effort: 3 (Moderate) | ~30 minutes

Change: Bug fix

Sequence Diagram(s)

sequenceDiagram
  participant PullRequestCodeTab
  participant getRenderablePatch
  participant hideWhitespaceChanges
  participant parseDiffFromFile
  PullRequestCodeTab->>getRenderablePatch: pass ignoreWhitespace
  getRenderablePatch->>hideWhitespaceChanges: filter parsed files
  hideWhitespaceChanges->>parseDiffFromFile: parse whitespace-stripped hunks
  parseDiffFromFile-->>hideWhitespaceChanges: return filtered hunk metadata
  hideWhitespaceChanges-->>getRenderablePatch: return files and sourceFiles
  getRenderablePatch-->>PullRequestCodeTab: render filtered diff

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Suggested reviewers: maria-rcks

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 20.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 5 functions across 3 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change: honoring whitespace settings in pull request diffs.
Description check	✅ Passed	The description explains the change, motivation, implementation, validation, UI impact, and includes before-and-after screenshots. It does not use the template headings or checklist, and it does not i…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

• Fix all pre-merge checks with AI

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create a new PR

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[Bil0000]

Leaving the nonblocking docstring-coverage warning unchanged: this task explicitly prohibits adding comments or docstrings unless requested. The behavior is covered by focused regression tests. CodeRabbit reported no actionable code findings, and CI passes at e534040477.