fix(sessions): repair migrated paths across short reads (#109400)

src/commands/doctor-state-migrations.test.ts

@@ -847,21 +847,39 @@ describe("doctor legacy state migrations", () => {
       },
     });
 
-    const detected = await detectLegacyStateMigrations({
-      cfg: {},
-      env: { OPENCLAW_STATE_DIR: root } as NodeJS.ProcessEnv,
-    });
-    expect(detected.preview).toContain(
-      `- Sessions: repair migrated transcript paths in ${path.join(targetDir, "sessions.json")}`,
-    );
+    const realReadSync = fs.readSync.bind(fs);
+    let shortReadCalls = 0;
+    const readSpy = vi.spyOn(fs, "readSync").mockImplementation(((
+      fd: number,
+      buffer: NodeJS.ArrayBufferView,
+      offset: number,
+      length: number,
+      position: fs.ReadPosition | null,
+    ) => {
+      shortReadCalls += 1;
+      return realReadSync(fd, buffer, offset, Math.min(length, 16), position);
+    }) as typeof fs.readSync);
 
-    const result = await runLegacyStateMigrations({ detected });
-    expect(result.warnings).toStrictEqual([]);
-    expect(result.changes).toContain("Repaired migrated session transcript paths");
-    const store = JSON.parse(
-      fs.readFileSync(path.join(targetDir, "sessions.json"), "utf8"),
-    ) as Record<string, object>;
-    expect(store["agent:main:main"]).not.toHaveProperty("sessionFile");
+    try {
+      const detected = await detectLegacyStateMigrations({
+        cfg: {},
+        env: { OPENCLAW_STATE_DIR: root } as NodeJS.ProcessEnv,
+      });
+      expect(detected.preview).toContain(
+        `- Sessions: repair migrated transcript paths in ${path.join(targetDir, "sessions.json")}`,
+      );
+
+      const result = await runLegacyStateMigrations({ detected });
+      expect(result.warnings).toStrictEqual([]);
+      expect(result.changes).toContain("Repaired migrated session transcript paths");
+      const store = JSON.parse(
+        fs.readFileSync(path.join(targetDir, "sessions.json"), "utf8"),
+      ) as Record<string, object>;
+      expect(store["agent:main:main"]).not.toHaveProperty("sessionFile");
+      expect(shortReadCalls).toBeGreaterThan(1);
+    } finally {
+      readSpy.mockRestore();
+    }
   });
 
   it("does not bind stale session metadata to a colliding target transcript", async () => {

src/infra/state-migrations.session-store.ts

@@ -29,6 +29,7 @@ import {
   parseAgentSessionKey,
 } from "../routing/session-key.js";
 import { normalizeSessionKeyPreservingOpaquePeerIds } from "../sessions/session-key-utils.js";
+import { readFileWindowFullySync } from "./file-read.js";
 import { sameFileIdentity } from "./fs-safe-advanced.js";
 import { expandHomePrefix } from "./home-dir.js";
 import { isWithinDir } from "./path-safety.js";
@@ -434,7 +435,7 @@ export function resolveStaleLegacySessionFile(params: {
     const fd = fs.openSync(targetSessionFile, "r");
     try {
       const buffer = Buffer.alloc(8192);
-      const bytesRead = fs.readSync(fd, buffer, 0, buffer.length, 0);
+      const bytesRead = readFileWindowFullySync(fd, buffer, 0);
       if (bytesRead <= 0) {
         return undefined;
       }