fix(thread-ownership): preserve conflict cancellation

mushuiyu886 · mushuiyu886 · commit 97d609c880df · 2026-07-08T11:04:22.000+08:00
diff --git a/extensions/thread-ownership/index.test.ts b/extensions/thread-ownership/index.test.ts
@@ -269,17 +269,40 @@ describe("thread-ownership plugin", () => {
       expect(infoMessage).toContain("cancelled send");
     });
 
-    it("fails open when the forwarder conflict JSON exceeds the bounded read limit", async () => {
+    it("cancels when the forwarder conflict JSON exceeds the bounded read limit", async () => {
       vi.mocked(globalThis.fetch).mockResolvedValue(
         new Response(JSON.stringify({ owner: "x".repeat(70 * 1024) }), { status: 409 }),
       );
 
       const result = await sendSlackThreadMessage();
 
-      expect(result).toBeUndefined();
-      const warningMessage = requireFirstLogMessage(api.logger.warn, "ownership check warning log");
-      expect(warningMessage).toContain("ownership check failed");
+      expect(result).toEqual({ cancel: true });
+      const warningMessage = requireFirstLogMessage(
+        api.logger.warn,
+        "ownership conflict warning log",
+      );
+      expect(warningMessage).toContain("conflict body unreadable");
       expect(warningMessage).toContain("JSON response exceeds 65536 bytes");
+      const infoMessage = requireFirstLogMessage(api.logger.info, "ownership cancel info log");
+      expect(infoMessage).toContain("cancelled send");
+      expect(infoMessage).toContain("owned by unknown");
+    });
+
+    it("cancels when the forwarder conflict JSON is malformed", async () => {
+      vi.mocked(globalThis.fetch).mockResolvedValue(new Response("{", { status: 409 }));
+
+      const result = await sendSlackThreadMessage();
+
+      expect(result).toEqual({ cancel: true });
+      const warningMessage = requireFirstLogMessage(
+        api.logger.warn,
+        "ownership conflict warning log",
+      );
+      expect(warningMessage).toContain("conflict body unreadable");
+      expect(warningMessage).toContain("malformed JSON response");
+      const infoMessage = requireFirstLogMessage(api.logger.info, "ownership cancel info log");
+      expect(infoMessage).toContain("cancelled send");
+      expect(infoMessage).toContain("owned by unknown");
     });
 
     it("fails open on network error", async () => {
diff --git a/extensions/thread-ownership/index.ts b/extensions/thread-ownership/index.ts
@@ -198,12 +198,21 @@ export default definePluginEntry({
             return undefined;
           }
           if (resp.status === 409) {
-            const body = await readProviderJsonResponse<{ owner?: unknown }>(
-              resp,
-              "thread-ownership forwarder conflict",
-              { maxBytes: FORWARDER_CONFLICT_JSON_MAX_BYTES },
-            );
-            const owner = typeof body.owner === "string" ? body.owner : undefined;
+            let owner = "unknown";
+            try {
+              const body = await readProviderJsonResponse<{ owner?: unknown }>(
+                resp,
+                "thread-ownership forwarder conflict",
+                { maxBytes: FORWARDER_CONFLICT_JSON_MAX_BYTES },
+              );
+              if (typeof body.owner === "string" && body.owner) {
+                owner = body.owner;
+              }
+            } catch (err) {
+              api.logger.warn?.(
+                `thread-ownership: conflict body unreadable (${String(err)}), cancelling send`,
+              );
+            }
             api.logger.info?.(
               `thread-ownership: cancelled send to ${channelId}:${threadTs} — owned by ${owner}`,
             );
