[Bug] extract_solution produces invalid source config for HamiltonianPath → ConsecutiveOnesSubmatrix

[zazabap]

Summary

The ILP solver finds a valid target solution for ConsecutiveOnesSubmatrix (Or(true)), but extract_solution maps back to a source config that evaluates to Or(false) for HamiltonianPath.

Reproduction

pred create --example HamiltonianPath -o hp.json
pred reduce hp.json --to ConsecutiveOnesSubmatrix -o bundle.json
pred solve bundle.json

Target evaluates to Or(true), extracted source config evaluates to Or(false).

Origin

Reduction implemented in PR #779.

Discovery Method

This bug was found by systematically running the full CLI round-trip pipeline (pred create --example → pred reduce → pred solve → pred evaluate) across all 43 reduction rules from PRs #777, #779, #804, #972. The existing Rust closed-loop unit tests pass because they test the direct API, but the CLI pipeline exercises serialization, registry lookup, and dynamic ILP path finding — a different code path that exposes extraction bugs.

Recommendation: Add a CI step or make target that runs this round-trip check for every rule with a canonical example. See #1005 for the proposal.

[zazabap]

Fix should include: Add assert_bf_vs_ilp (from src/rules/test_helpers.rs) to this reduction's closed-loop test. The helper already exists and is used by 56 other tests — this reduction just wasn't wired up to it. The current test only verifies extraction with brute-force witnesses, which happen to work. ILP finds structurally different valid witnesses that break extraction.

[zazabap]

Superseded by #1006. Root cause is unsound reduce_to() constructions, not extract_solution bugs.