fix(tooling): marker guard false-positives on changes deep inside a pre-existing block

[anandgupta42]

What does this PR do?

Fixes the Marker Guard CI job, which went red on main (commit 89699f6919, the #895 merge) by false-positiving on packages/opencode/src/cli/cmd/tui/worker.ts:183 — a line that is correctly wrapped in an altimate_change block.

Root cause: parseDiffForMarkerWarnings derived marker state only from the lines visible in each diff hunk (git diff -U5 → ±5 context lines). When a line is modified deep inside a large pre-existing altimate_change block, the block's start marker sits outside the context window and never appears in the hunk, so inMarkerBlock stays false and the change is mis-flagged as unmarked. The per-hunk marker-state reset compounded it.

Fix: compute marker coverage from the full post-change file and pass it into the parser:

• computeMarkedLines(content) — full-file, depth-counted coverage set (handles nested start/end pairs, which a single openBlock would miss).
• parseDiffForMarkerWarnings(file, diff, markedLines?) — a changed line is covered if the in-hunk tracker saw its start or the full-file map says it's inside a marked block. The map can only suppress false positives, never add new ones — so all existing warning behavior is preserved.
• checkFileForMarkers reads git show HEAD:<file> (or the working tree for base-less runs) and feeds the map in.

Type of change

• Bug fix (non-breaking change which fixes an issue)

Issue for this PR

Closes #876

How did you verify your code works?

• 11 new unit tests in script/upstream/analyze.test.ts: nesting, unbalanced markers, and the exact context-window false positive (with/without coverage map, plus an end-to-end reconstruction). Full file: 29/29 pass.
• Reproduced the real failure: analyze.ts --markers --base 7e909a9777 --strict (the exact base the CI job used) flags worker.ts:183 with the original code and passes with the fix. Reverting the fix reproduces the failure.

Checklist

• My code follows the style guidelines of this project
• I have added tests that prove my fix is effective
• New and existing unit tests pass locally with my changes
• I have made corresponding changes to the documentation (n/a — internal tooling)

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Summary by cubic

Fix Marker Guard false positives when editing lines deep inside a pre-existing altimate_change block. CI no longer misflags valid changes, and genuine warnings are unchanged.

• Bug Fixes
  • Added computeMarkedLines for full-file, nesting-aware marker coverage.
  • Updated parseDiffForMarkerWarnings to take a coverage map; a line is covered if seen in-hunk or in the map.
  • checkFileForMarkers now reads the post-change file to supply coverage; added tests for the context-window case and nested markers. Closes fix(tooling): marker-guard false-positive across tags — carry marker state across diff hunks #876.

^{Written for commit d54778f. Summary will update on new commits.}

Summary by CodeRabbit

• Bug Fixes

  • Fixed false positive warnings for code changes occurring within pre-existing marked regions when the corresponding start marker is outside the diff context window.

• Tests

  • Added comprehensive unit tests for marker coverage computation, including validation of nested marker pairs, edge cases, and integration testing to ensure marked regions are properly recognized across file contexts.

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Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: be2b158e-3266-4bbd-a6e5-2f11d7155b0f

📥 Commits

Reviewing files that changed from the base of the PR and between d2cf6b3 and d54778f.

📒 Files selected for processing (2)

• script/upstream/analyze.test.ts
• script/upstream/analyze.ts

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📝 Walkthrough

Walkthrough

The PR extends marker-based change detection to fix false positives when altimate_change start markers fall outside diff context windows. A new computeMarkedLines function scans entire files to build full coverage maps, which are then fed into the updated parseDiffForMarkerWarnings parser to suppress warnings for changes within pre-existing marked blocks regardless of hunk boundaries.

Changes

Full-file marker coverage and false-positive suppression

Layer / File(s)	Summary
Full-file marker coverage computation script/upstream/analyze.ts	New computeMarkedLines(content) function scans file content, tracks nested altimate_change start/end markers via depth counter, and returns set of all line numbers within any marked region.
Parser signature extension for coverage map script/upstream/analyze.ts	parseDiffForMarkerWarnings now accepts optional markedLines set parameter for full-file coverage in addition to diff-context marker tracking.
Marker violation logic with dual coverage script/upstream/analyze.ts	Marker violation check updated to suppress warnings when a changed line is covered by either diff-context marker state or full-file coverage map, preventing false positives when start marker is outside context window.
Full-file coverage computation and integration script/upstream/analyze.ts	Script now reads post-change file content (via git show or disk), computes full-file marked lines using computeMarkedLines, and passes coverage set into parseDiffForMarkerWarnings for each checked file.
Test coverage for marker detection script/upstream/analyze.test.ts	Unit tests for computeMarkedLines covering basic blocks, nested marker pairs via depth tracking, and unbalanced end markers; integration tests for parseDiffForMarkerWarnings with coverage map parameter verifying suppression of false positives and retention of valid warnings.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related issues

• #898: Addresses nested marker handling in script/upstream/analyze.ts with depth/stack tracking for altimate_change markers, related to the marker-depth logic in this PR.

Possibly related PRs

• AltimateAI/altimate-code#782: Addresses the same underlying false-positive marker warning issue during bridge/upstream-merge commits but at the CI workflow level rather than in the detection algorithm itself.

Suggested labels

contributor, needs-review:blocked

Poem

🐰 Through nested markers deep and wide,
The coverage map becomes our guide—
No false alarms when blocks align,
Full-file scanning draws the line!
A hop, a skip, no context gaps—
Just marked lines tracked on coverage maps. 🎯

✨ 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 fix/marker-guard-context-window

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