refactor(tool): use structured udiff hunks for diff metadata

[omarluq]

No description provided.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: be7db77e-5e2c-450d-9321-d28d22f56b9c

📥 Commits

Reviewing files that changed from the base of the PR and between cd3be74 and 09b83b2.

📒 Files selected for processing (1)

• internal/terminal/tool_blocks.go

🚧 Files skipped from review as they are similar to previous changes (1)

• internal/terminal/tool_blocks.go

---

📝 Walkthrough

Summary by CodeRabbit

• Refactor
  • Updated tool edit diff rendering to use standardized unified diffs with configurable context, producing cleaner combined output across multiple edits.
  • Improved diff generation internals to compute first-changed line numbers from unified-diff hunks rather than parsing diff text.
• Tests
  • Expanded diff-related internal coverage, including verification of inserted-line reporting and first-changed line behavior.

Walkthrough

Two diff-rendering implementations are replaced with structured go-udiff API usage. tool_blocks.go drops manual -/+ prefix writing in favor of per-edit unified diffs via a new diffFromEditArgumentTexts helper. diff.go removes string-parsing helpers for hunk headers and rewrites firstChangedLineFromUnifiedDiff to iterate udiff.UnifiedDiff hunks and line kinds directly.

Changes

Unified diff refactor using go-udiff structured API

Layer / File(s)	Summary
tool_blocks: replace manual prefix diff with udiff helper internal/terminal/tool_blocks.go	Adds go-udiff import and toolArgumentDiffContext constant. Rewrites diffFromEditArguments to delegate per-edit diff generation to new diffFromEditArgumentTexts, which calls udiff.Lines + udiff.ToUnifiedDiff and returns a trimmed unified diff string. Removes old writePrefixedDiffLines logic.
diff.go: switch to udiff.ToUnifiedDiff and structured hunk iteration internal/tool/diff.go, internal/tool/diff_internal_test.go	generateDiffString switches from udiff.ToUnified to udiff.ToUnifiedDiff; truncation operates on diff.String(). firstChangedLineFromUnifiedDiff is rewritten to iterate udiff.UnifiedDiff hunks and line kinds, removing all string-parsing helpers (parseUnifiedHunkStart, parseUnifiedRange, normalizeUnifiedLineNumber) and strconv/strings imports. Test removes unifiedHunkStartCase struct and adds an insertion-detection case.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related PRs

• omarluq/librecode#96: Directly related — rewrites internal/tool/diff.go to use go-udiff, establishing the unified diff pipeline that this PR further refactors.

Poem

🐇 Hoppity hop through the diff lines I go,
No more parsing @@ headers — what a show!
Structured hunks now tell me where changes reside,
udiff.Insert and Delete are my trusty guide.
The old string-splitter's gone, hooray!
Clean unified diffs are here to stay. ✨

🚥 Pre-merge checks | ✅ 3 | ❌ 1

❌ Failed checks (1 inconclusive)

Check name	Status	Explanation	Resolution
Description check	❓ Inconclusive	No description was provided by the author, making it impossible to assess relatedness to the changeset.	Add a pull request description explaining the motivation, approach, and benefits of switching to structured udiff hunks.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically describes the main refactoring change: replacing custom diff parsing logic with structured udiff hunks for extracting diff metadata.
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.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch chore/diffs

---

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[codecov]

Codecov Report

❌ Patch coverage is 75.75758% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 80.43%. Comparing base (651ae84) to head (09b83b2).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/terminal/tool_blocks.go	68.42%	3 Missing and 3 partials ⚠️
internal/tool/diff.go	85.71%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #145      +/-   ##
==========================================
- Coverage   80.45%   80.43%   -0.03%     
==========================================
  Files         277      277              
  Lines       21925    21888      -37     
==========================================
- Hits        17640    17605      -35     
- Misses       3074     3075       +1     
+ Partials     1211     1208       -3     

Flag	Coverage Δ
unittests	80.43% <75.75%> (-0.03%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@internal/terminal/tool_blocks.go`:
- Around line 571-575: The builder.WriteByte and builder.WriteString calls in
this block are not checking their error return values, which violates the coding
guidelines requiring explicit error handling with errcheck enabled. Capture the
error return values from both the builder.WriteByte('\n') call on line 572 and
the builder.WriteString(diff) call on line 575, then add appropriate error
handling to check and respond to these potential write failures rather than
dropping the returned errors.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 3e34180b-1068-4cca-8a30-d24e91d116e5

📥 Commits

Reviewing files that changed from the base of the PR and between 651ae84 and cd3be74.

📒 Files selected for processing (3)

• internal/terminal/tool_blocks.go
• internal/tool/diff.go
• internal/tool/diff_internal_test.go

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud