[Bug] extract_solution produces invalid source config for ThreePartition → JobShopScheduling

[zazabap]

Summary

Brute-force solver finds a target solution with Min(61) for JobShopScheduling, but extract_solution maps back to all-zeros source config [0,0,0,0,0,0] which evaluates to Or(false) for ThreePartition.

Reproduction

pred create --example ThreePartition -o tp.json
pred reduce tp.json --to JobShopScheduling -o bundle.json
pred solve bundle.json --solver brute-force

Result: Target evaluates to Min(61), extracted source config is all-zeros → Or(false).

The solver minimizes makespan globally without checking the deadline feasibility threshold. The back-extraction then produces an invalid group assignment.

Origin

Reduction implemented in PR #972.

[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Superseded by #1006.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.