id: "GW20-014"
title: "Prepare lawful Strand settlement after the target advances"
type: "feature"
status: "planned"
milestone: "v20.1.0"
category: "required"
workstream: "runtime"
issue: "#970"
baseline_commit: "ceb58e656ec5bc85f0ae5991bf2a55599693bbb3"
feedback_sections: [10]
prerequisites: ["GW20-001", "GW20-009"]

Feature

LLM prompt

Complete GW20-014: Prepare lawful Strand settlement after the target advances.
Read this entire task and its current GitHub issue before implementation.
Verify the current mainline and all prerequisite integrations.
Read AGENTS.md and the three TypeScript policy documents.
Use runtime-backed domain values and injected ports.
Keep parsing and codecs at the adapter boundary.
Preserve v20 APIs, stored identities, CRDT semantics, and failure meanings.
Use one coherent issue, PR, and mainline integration. Do not leave a broken intermediate state.
Problem to resolve:
Settlement refuses every advanced target with settlement-common-basis-required. A live collaboration flow cannot prepare a lawful current-target settlement.
Acceptance checks:
Provide an explicit supported preparation path that compares strand claims at a retained common basis after target advancement.
Independent edits can produce an executable reviewed plan without erasing target work.
Conflicting edits preserve obstruction or plurality unless the selected law authorizes resolution.
Plan evidence records original fork, current target, proposal, law, and policy.
Target advancement after preview still refuses a stale plan. Repeated requests do not duplicate publication.
Preserve existing v20 refusal meanings. Keep unsupported general settlement families explicit.
Existing previewSettlement and settle calls keep settlement-common-basis-required for an advanced target by default.
Expose common-basis preparation as an explicit additive operation. Do not silently normalize the existing default path.
Record the supported normalization law and an evidence mapping from original claims to the prepared proposal. Generic merge families remain unsupported.
Read these source paths:
src/application/RuntimeSettlement.ts
src/domain/api/DraftSettlementRuntime.ts
test/integration/application/Runtime.settlement.integration.test.ts
Prerequisites: #957, #965
Scope exclusions: Force a winner, redefine existing obstructions, or silently implement every future BTR/merge family.
Run all tests and benchmarks in COPY-based Docker without host repository mounts.
Use the project guarded runner and the shared git-locks authority.
Lock host/heavy-work and the exact worker key together for expensive work.
Limit build caches to 20 GiB, test data to 4 GiB, and logs to 128 MiB.
Require 50 GiB free on host and Docker backing storage before heavy work.
Enforce disk accounting, CPU, memory, timeout, and child-process shutdown.
Do not start an unguarded workload. Do not bypass a resource refusal.
Require full touched-code coverage for refactors and an all-green manual SSJS scorecard.
Record source, image, command, fixtures, results, limits, and the regression witness.
Commit only your own files. Do not amend, rebase, force, push, or publish without authorization.
Report incomplete or blocked checks. Do not claim completion from a narrow green test.
Link the issue, coherent PR, and actual mainline integration when those actions are authorized.

1. Background Context

Source: FEEDBACK-git-warp.md, sections 10.
The report SHA-256 is 9b15209d51cd705059a9e6bfebf0f6681ff832924c1462b99ff3cfebde6bacae.
The report uses npm git-warp 20.0.0 and git-cas 6.5.11.
Its runtime results come from macOS host experiments. This planning task did not rerun them.
Source review baseline: ceb58e65.

Tracker: #970.

Read these source and test surfaces before work:

• src/application/RuntimeSettlement.ts
• src/domain/api/DraftSettlementRuntime.ts
• test/integration/application/Runtime.settlement.integration.test.ts

2. Problem Description

Settlement refuses every advanced target with settlement-common-basis-required. A live collaboration flow cannot prepare a lawful current-target settlement.

2b. Proposed Solution

Add an explicit common-basis preparation operation for the supported intent contract. Revalidate the immutable plan before publication.

2c. Alternatives considered and rejected

Reject a private-import workaround. It does not provide a supported application contract.
Reject a documentation-only substitute when this task requires runtime behavior.
Keep larger storage and package redesigns under their existing issues.

2d. Acceptance Criteria

• Provide an explicit supported preparation path that compares strand claims at a retained common basis after target advancement.
• Independent edits can produce an executable reviewed plan without erasing target work.
• Conflicting edits preserve obstruction or plurality unless the selected law authorizes resolution.
• Plan evidence records original fork, current target, proposal, law, and policy.
• Target advancement after preview still refuses a stale plan. Repeated requests do not duplicate publication.
• Preserve existing v20 refusal meanings. Keep unsupported general settlement families explicit.
• Existing previewSettlement and settle calls keep settlement-common-basis-required for an advanced target by default.
• Expose common-basis preparation as an explicit additive operation. Do not silently normalize the existing default path.
• Record the supported normalization law and an evidence mapping from original claims to the prepared proposal. Generic merge families remain unsupported.

2e. Test Plan

Golden: Fork, edit separate properties on source and target, prepare and review at a common basis, settle, reopen, and verify both edits.

Edges: Same-property conflict; removals; missing support; target advancement during preview; replay; foreign plan; unchanged target.

Known failure modes: preserve typed refusal, atomic publication, and complete evidence. Do not conceal unavailable support.

Fuzz and stress: use fixed fixture sizes and seeds. Apply the roadmap resource guards. Do not start an unbounded campaign.

3. Prerequisites

• Advance new writer Lamports beyond the observed Lane frontier #957 must be integrated. Settlement must preserve causal order when it publishes after observed target changes.
• Export and restore Coordinates without private factories #965 must be integrated. Common-basis plans need validated portable coordinate references.

4. Scope

In: Settlement refuses every advanced target with settlement-common-basis-required. A live collaboration flow cannot prepare a lawful current-target settlement.

Out: Force a winner, redefine existing obstructions, or silently implement every future BTR/merge family.

Safe intermediate state: one independently mergeable PR passes its relevant checks after its prerequisites.
Existing supported applications remain usable. Historical data remains intact.

5. Why now

This flaw blocks a supported Synapse store workflow or gives its operator incorrect guidance.
Resolve it within v20.1.0 without reducing the existing causal-history commitment.

6. Risks

Source inspection does not establish runtime or performance results.
Preserve historical identities, validation, and evidence. Do not weaken refusal to obtain a green result.
If the fix requires a breaking contract, record the conflict before activation. Do not hide it within a minor release.

7. Definition of Done

All acceptance checks have evidence from the exact candidate.
Relevant lint, typecheck, compatibility, and Docker checks pass.
The manual SSJS scorecard is green. Refactor coverage reaches 100% on touched code.
Record the issue, PR, and mainline integration commit. Record any external release gate.
A required check with missing evidence remains incomplete.

8. Stakeholders

James Ross: git-warp maintainer and acceptance owner.
Synapse store authors: applications need correct writes, reads, history, and operational guidance.
Library and CLI consumers: existing v20 contracts must remain usable.

9. Related Issues

• #466
• #711
• #793