[stugorf]

Problem and change

Resolves #13. Eligible variable-length paths use one resumable depth-first CSR operator for the complete hop range. Mixed-label alternation remains typed until execution; unsupported shapes keep the join fallback. Output chunks are bounded and the 20-hop limit remains.

Zero-hop paths use source identity in both execution routes, including label identity when integer keys overlap. Duplicate paths and the existing immediate-backtracking rule are preserved. Rust callers constructing LogicalOperator::VariableLengthExpand provide target_label; Python signatures are unchanged.

Validation

Head c6bc5c150a2e198e2346e1870509db0f4ce69887; frozen parent e127755c872949733c69435047384c9d17fb572b. Focused checks and regression details record commands, results, documentation and compatibility. The release receipt pins wheel/archive identity and 347 installed tests.

Both complete workloads pass unchanged goldens in memory and lazy modes. Retained first-pass geometric mean speedups are below (greater than one is faster). Per-query results and paired investigations remain in the audit archive.

Workload/mode	Main	Actual parent
Q30 memory	1.052	1.075
Q30 lazy	0.988	1.058
IC memory	1.252	1.273
IC lazy	1.198	1.184

Measurements use the same Apple M4 Max (16 cores, 128 GiB), macOS 26.6.2 arm64 and Python 3.13.17, with Q30 revision 6260689 and IC revision c185123. Reproduction instructions pin settings, data checksums, locks and commands. The frozen main baseline is code-identical to current main 90114f3; the equivalence check also verifies clean prospective main-target merges.

This is a coordinated draft. Preserve its frozen-head outcomes and apply the shared corrections in the qualified integration; changing the actual target requires requalification. The accepted combined engine source is 7d2ef3e; its current-main documentation merge is 5fe24cd.

User impact

Eligible typed paths use one iterative operator; true zero-hop identity is corrected and the 20-hop limit remains. Rust VariableLengthExpand constructors supply target_label. Cypher/CSR limits and migration notes are updated.

Review ledger · Current contribution guide

Audit archive: 47,675,190 bytes; SHA-256 b3486fb30a34639c830b5d49353b3838f96369f95df959ac35f85511f7f8b2de. The small current-main supplement preserves the documentation update. Original absolute paths in receipts map to included records through the archive index.

Submitted by David Hughes (@stugorf), with AI Collaboration.

[prrao87]

This change merged into an intermediate branch, not main. It reached main through #55, which brought in the final integrated version of this work with every original commit kept on its branch. Follow-up fixes from review are listed there.