The correspondence mapped an equal-region base<->head line pair only when the
line's content was GLOBALLY unique in the file, so common lines (`}`, blanks,
imports) tripped `ambiguous_line_correspondence` and the finding's anchor was
discarded -> the operation came back `unmapped` -> novelty `unknown` ->
`comparison_unknown` -> the engine finding was suppressed (a direct cause of
"near-blind to fixes").
Replace the global-uniqueness gate with run-aware positional anchoring: segment
the equal-region pairs into contiguous runs (strictly +1/+1, as _equal_line_pairs
emits), and map a pair when its content occupies exactly one old run and one new
run. Duplicates WITHIN a contiguous run are positionally forced and now map;
duplicates ACROSS runs split by an edit are aligned arbitrarily by git and stay
withheld + flagged (soundness preserved -- the moved-repeated-operation guard
still passes, so no false `new`/identity claims).
Tests: update test_change_context_unknown_base_binary_and_ambiguous_lines_are_
unresolved (its two in-run sinks now anchor); keep the moved-operation soundness
test; add intra-run-maps, cross-run-withheld, and distinctive-line-anchors cases.
163 push tests pass, ruff clean.
Honest scope (design.md amendment): this removes one real cause but is
necessary-not-sufficient -- live-testing a messy 14-file Java change showed
coverage stays `incomplete` due to other, dominant blockers (capability_unavailable
until Task 8.3; the engine produced no actionable defect; eligibility/projection
gaps). Engine coverage on unseen diffs needs those too, not just correspondence.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
ChangeContext records the paths Git reports as added. An entailed,
undischarged operation in an added file, with complete head evidence and no
identical operation in any base answer, is classified new
(file_added_in_head) instead of base_incomplete; admission accepts that reason
as change evidence. Unpaired add/delete pushes and every other unknown
comparison keep their vetoes. An engine finding whose novelty is established
and whose only vetoes are capability vetoes is shown as an advisory engine
finding, not an alert. Requirement 9.4.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01EmM1j46qgKMh3zqD1QMwEo
