Follow-up to #38. #38 made undo/redo re-inserted text neutral (no false human
coloring); #40 restores its EXACT prior attribution so Claude's restored text is
blue again, the human's green.
Mechanism — text-keyed attribution snapshots: per-doc Map<documentText, spans>,
snapshotted after every forward edit + at load; on undo/redo, after the #38
geometry reconcile, if a snapshot's text equals the current buffer the spans are
restored exactly (offsets valid — identical text). Robust to VS Code undo
coalescing (only the resulting-text-matching event restores); far-back/evicted
states fall back to #38 neutral. History bounded (ATTR_HISTORY_MAX, oldest
evicted).
NOT MERGED / NOT VERIFIED END-TO-END: 222 unit + typecheck green, but the #40
host E2E (and the pre-existing #38 undoMarks E2E) depend on
executeCommand("undo"), which is broken in this test environment — the untouched
#38 test fails identically on clean main (the known undoMarks flake, now
deterministic). Clearing .vscode-test/user-data (the usual remedy) is
permission-blocked here. The operator should verify in a working E2E environment
before merging.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Ben Stull
5645b926a3