feat(#194): Phase 1 — parentState / childThread in CAS nodes

- Protocol: StartNodePayload.parentState, StateNodePayload.childThread
- CAS: putStartNode refs include parentState, collectRefs includes childThread
- Parsing: legacy nodes without new fields default to null
- Engine + fork: all callers pass parentState: null / childThread: null
- Tests: 8 new cases for refs, parsing, collect-refs (+208 lines)

Phase 1 of #194 (Merkle Call Stack). Closes #195.

小橘 <xiaoju@shazhou.work>

packages/cli-workflow/__tests__/gc-cli.test.ts

@@ -45,8 +45,8 @@ describe("gc cli and garbageCollectCas", () => {
       {
         name: "demo",
         hash: bundleHash,
-
         depth: 0,
+        parentState: null,
       },
       promptHash,
     );
@@ -100,8 +100,8 @@ describe("gc cli and garbageCollectCas", () => {
       {
         name: "demo",
         hash: bundleHash,
-
         depth: 0,
+        parentState: null,
       },
       promptHash,
     );
@@ -135,8 +135,8 @@ describe("gc cli and garbageCollectCas", () => {
       {
         name: "demo",
         hash: bundleHash,
-
         depth: 0,
+        parentState: null,
       },
       promptHash,
     );

packages/workflow-cas/__tests__/collect-refs.test.ts

@@ -14,6 +14,7 @@ function payload(
     ancestors: partial.ancestors ?? [],
     compact: partial.compact ?? null,
     timestamp: partial.timestamp ?? 0,
+    childThread: partial.childThread ?? null,
   };
 }
 
@@ -62,4 +63,32 @@ describe("collectRefs", () => {
     );
     expect(refs).toEqual(["S2", "C2"]);
   });
+
+  test("includes childThread hash when childThread is non-null", () => {
+    const refs = collectRefs(
+      payload({
+        role: "developer",
+        start: "S3",
+        content: "C3",
+        ancestors: ["A3"],
+        compact: null,
+        childThread: "CHILDEND000000000000001",
+      }),
+    );
+    expect(refs).toEqual(["S3", "C3", "A3", "CHILDEND000000000000001"]);
+  });
+
+  test("does not include childThread when childThread is null", () => {
+    const refs = collectRefs(
+      payload({
+        role: "developer",
+        start: "S4",
+        content: "C4",
+        ancestors: [],
+        compact: null,
+        childThread: null,
+      }),
+    );
+    expect(refs).toEqual(["S4", "C4"]);
+  });
 });

packages/workflow-cas/__tests__/nodes.test.ts

@@ -0,0 +1,161 @@
+import { afterEach, beforeEach, describe, expect, test } from "bun:test";
+import { mkdtemp, rm } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { stringify } from "yaml";
+
+import { createCasStore } from "../src/cas.js";
+import { parseCasThreadNode, putStartNode, putStateNode } from "../src/nodes.js";
+
+describe("putStartNode — parentState in refs", () => {
+  let dir: string;
+
+  beforeEach(async () => {
+    dir = await mkdtemp(join(tmpdir(), "wf-cas-nodes-"));
+  });
+
+  afterEach(async () => {
+    await rm(dir, { recursive: true, force: true });
+  });
+
+  test("refs contains only promptHash when parentState is null", async () => {
+    const cas = createCasStore(join(dir, "cas"));
+    const promptHash = await cas.put("hello");
+    const startHash = await putStartNode(
+      cas,
+      { name: "demo", hash: "BUNDLEAAAAAAAAA", depth: 0, parentState: null },
+      promptHash,
+    );
+
+    const blob = await cas.get(startHash);
+    expect(blob).not.toBeNull();
+    const parsed = parseCasThreadNode(blob ?? "");
+    expect(parsed).not.toBeNull();
+    expect(parsed?.kind).toBe("start");
+    if (parsed?.kind !== "start") return;
+
+    expect(parsed.node.refs).toEqual([promptHash]);
+    expect(parsed.node.payload.parentState).toBeNull();
+  });
+
+  test("refs contains [promptHash, parentStateHash] when parentState is set", async () => {
+    const cas = createCasStore(join(dir, "cas"));
+    const parentStateHash = await cas.put("fake-parent-state");
+    const promptHash = await cas.put("child-prompt");
+    const startHash = await putStartNode(
+      cas,
+      { name: "develop", hash: "BUNDLEBBBBBBBBB", depth: 1, parentState: parentStateHash },
+      promptHash,
+    );
+
+    const blob = await cas.get(startHash);
+    expect(blob).not.toBeNull();
+    const parsed = parseCasThreadNode(blob ?? "");
+    expect(parsed).not.toBeNull();
+    expect(parsed?.kind).toBe("start");
+    if (parsed?.kind !== "start") return;
+
+    expect(parsed.node.refs).toEqual([promptHash, parentStateHash]);
+    expect(parsed.node.payload.parentState).toBe(parentStateHash);
+  });
+});
+
+describe("putStateNode — childThread in refs", () => {
+  let dir: string;
+
+  beforeEach(async () => {
+    dir = await mkdtemp(join(tmpdir(), "wf-cas-nodes-state-"));
+  });
+
+  afterEach(async () => {
+    await rm(dir, { recursive: true, force: true });
+  });
+
+  test("refs does not include childThread when childThread is null", async () => {
+    const cas = createCasStore(join(dir, "cas"));
+    const startHash = await cas.put("start");
+    const contentHash = await cas.put("content");
+    const stateHash = await putStateNode(cas, {
+      role: "planner",
+      meta: {},
+      start: startHash,
+      content: contentHash,
+      ancestors: [],
+      compact: null,
+      timestamp: 1000,
+      childThread: null,
+    });
+
+    const blob = await cas.get(stateHash);
+    expect(blob).not.toBeNull();
+    const parsed = parseCasThreadNode(blob ?? "");
+    expect(parsed?.kind).toBe("state");
+    if (parsed?.kind !== "state") return;
+
+    expect(parsed.node.refs).not.toContain("anything-else");
+    expect(parsed.node.refs).toEqual([startHash, contentHash]);
+    expect(parsed.node.payload.childThread).toBeNull();
+  });
+
+  test("refs includes childThread hash when childThread is set", async () => {
+    const cas = createCasStore(join(dir, "cas"));
+    const startHash = await cas.put("start");
+    const contentHash = await cas.put("content");
+    const childEndHash = await cas.put("child-end-state");
+    const stateHash = await putStateNode(cas, {
+      role: "developer",
+      meta: { pr: 42 },
+      start: startHash,
+      content: contentHash,
+      ancestors: [],
+      compact: null,
+      timestamp: 2000,
+      childThread: childEndHash,
+    });
+
+    const blob = await cas.get(stateHash);
+    expect(blob).not.toBeNull();
+    const parsed = parseCasThreadNode(blob ?? "");
+    expect(parsed?.kind).toBe("state");
+    if (parsed?.kind !== "state") return;
+
+    expect(parsed.node.refs).toContain(childEndHash);
+    expect(parsed.node.payload.childThread).toBe(childEndHash);
+  });
+});
+
+describe("parseCasThreadNode — legacy node compatibility", () => {
+  test("start node without parentState field defaults to null", () => {
+    const yaml = stringify({
+      type: "start",
+      payload: { name: "demo", hash: "BUNDLEAAAAAAAAA", depth: 0 },
+      refs: ["PROMPTHASH00001"],
+    });
+    const parsed = parseCasThreadNode(yaml);
+    expect(parsed).not.toBeNull();
+    expect(parsed?.kind).toBe("start");
+    if (parsed?.kind !== "start") return;
+    expect(parsed.node.payload.parentState).toBeNull();
+  });
+
+  test("state node without childThread field defaults to null", () => {
+    const yaml = stringify({
+      type: "state",
+      payload: {
+        role: "planner",
+        meta: {},
+        start: "STARTHASH00001",
+        content: "CONTENTHASH0001",
+        ancestors: [],
+        compact: null,
+        timestamp: 1000,
+      },
+      refs: ["STARTHASH00001", "CONTENTHASH0001"],
+    });
+    const parsed = parseCasThreadNode(yaml);
+    expect(parsed).not.toBeNull();
+    expect(parsed?.kind).toBe("state");
+    if (parsed?.kind !== "state") return;
+    expect(parsed.node.payload.childThread).toBeNull();
+  });
+});

packages/workflow-execute/__tests__/gc-mark-sweep.test.ts

@@ -46,6 +46,7 @@ describe("garbageCollectCas (mark-and-sweep)", () => {
         name: "demo",
         hash: bundleHash,
         depth: 0,
+        parentState: null,
       },
       promptHash,
     );
@@ -59,6 +60,7 @@ describe("garbageCollectCas (mark-and-sweep)", () => {
       ancestors: [],
       compact: null,
       timestamp: 1,
+      childThread: null,
     } satisfies StateNodePayload);
 
     const c2 = await putContentNodeWithRefs(cas, "c1", []);
@@ -70,6 +72,7 @@ describe("garbageCollectCas (mark-and-sweep)", () => {
       ancestors: [h1],
       compact: null,
       timestamp: 2,
+      childThread: null,
     } satisfies StateNodePayload);
 
     const ec = await putContentNodeWithRefs(cas, "", []);
@@ -81,6 +84,7 @@ describe("garbageCollectCas (mark-and-sweep)", () => {
       ancestors: [h1],
       compact: null,
       timestamp: 3,
+      childThread: null,
     } satisfies StateNodePayload);
 
     await upsertThreadEntry(bundleDir, "THREAD_AAAAAAA", {

packages/workflow-execute/src/engine/engine.ts

@@ -112,6 +112,7 @@ async function appendStateForStep(params: {
     ancestors,
     compact: null,
     timestamp: params.timestamp,
+    childThread: null,
   };
   const stateHash = await putStateNode(params.cas, payload);
   return {
@@ -137,6 +138,7 @@ async function appendEndState(params: {
     ancestors,
     compact: null,
     timestamp: params.timestamp,
+    childThread: null,
   };
   return putStateNode(params.cas, payload);
 }
@@ -439,6 +441,7 @@ export async function executeThread(
         name: workflowName,
         hash: io.hash,
         depth: options.depth,
+        parentState: null,
       },
       promptHash,
     );

packages/workflow-execute/src/engine/fork-thread.ts

@@ -240,6 +240,7 @@ async function buildForkContinuation(params: {
     ancestors: ancestorsMarker,
     compact: null,
     timestamp: Date.now(),
+    childThread: null,
   };
   const markerHash = await putStateNode(cas, markerPayload);
 

packages/workflow-runtime/__tests__/build-context.test.ts

@@ -27,7 +27,7 @@ describe("buildThreadContext", () => {
     const bundleHash = "BHAAAAAAAAAAA";
     const startHash = await putStartNode(
       cas,
-      { name: "demo", hash: bundleHash, depth: 2 },
+      { name: "demo", hash: bundleHash, depth: 2, parentState: null },
       promptHash,
     );
 
@@ -41,6 +41,7 @@ describe("buildThreadContext", () => {
       ancestors: [],
       compact: null,
       timestamp: 1000,
+      childThread: null,
     });
 
     const chCode = await putContentNodeWithRefs(cas, "code body", []);
@@ -52,6 +53,7 @@ describe("buildThreadContext", () => {
       ancestors: [statePlan],
       compact: null,
       timestamp: 2000,
+      childThread: null,
     });
 
     const ctx = await buildThreadContext(stateCode, cas);
@@ -71,7 +73,7 @@ describe("buildThreadContext", () => {
     const promptHash = await cas.put("only-prompt");
     const startHash = await putStartNode(
       cas,
-      { name: "solo", hash: "BHBBBBBBBBBBB", depth: 1 },
+      { name: "solo", hash: "BHBBBBBBBBBBB", depth: 1, parentState: null },
       promptHash,
     );
 
@@ -87,7 +89,7 @@ describe("buildThreadContext", () => {
     const bundleHash = "BHCCCCCCCCCCC";
     const startHash = await putStartNode(
       cas,
-      { name: "demo", hash: bundleHash, depth: 0 },
+      { name: "demo", hash: bundleHash, depth: 0, parentState: null },
       promptHash,
     );
 
@@ -100,6 +102,7 @@ describe("buildThreadContext", () => {
       ancestors: [],
       compact: null,
       timestamp: 500,
+      childThread: null,
     });
 
     const endContent = await putContentNodeWithRefs(cas, "finished", []);
@@ -111,6 +114,7 @@ describe("buildThreadContext", () => {
       ancestors: [state1],
       compact: null,
       timestamp: 600,
+      childThread: null,
     });
 
     const ctx = await buildThreadContext(endState, cas);