race condition

orchestrator/src/server/db/migrate.ts

@@ -451,6 +451,25 @@ const migrations = [
   `CREATE INDEX IF NOT EXISTS idx_job_chat_threads_job_updated ON job_chat_threads(job_id, updated_at)`,
   `CREATE INDEX IF NOT EXISTS idx_job_chat_messages_thread_created ON job_chat_messages(thread_id, created_at)`,
   `CREATE INDEX IF NOT EXISTS idx_job_chat_runs_thread_status ON job_chat_runs(thread_id, status)`,
+  // Ensure only one running run per thread; backfill any duplicates first.
+  `WITH ranked AS (
+      SELECT
+        id,
+        ROW_NUMBER() OVER (PARTITION BY thread_id ORDER BY started_at DESC, id DESC) AS rank_in_thread
+      FROM job_chat_runs
+      WHERE status = 'running'
+    )
+    UPDATE job_chat_runs
+    SET
+      status = 'failed',
+      error_code = COALESCE(error_code, 'CONFLICT'),
+      error_message = COALESCE(error_message, 'Recovered duplicate running run during migration'),
+      completed_at = COALESCE(completed_at, CAST(strftime('%s', 'now') AS INTEGER)),
+      updated_at = datetime('now')
+    WHERE id IN (SELECT id FROM ranked WHERE rank_in_thread > 1)`,
+  `CREATE UNIQUE INDEX IF NOT EXISTS idx_job_chat_runs_thread_running_unique
+   ON job_chat_runs(thread_id)
+   WHERE status = 'running'`,
 
   // Backfill: Create "Applied" events for legacy jobs that have applied_at set but no event entry
   `INSERT INTO stage_events (id, application_id, title, from_stage, to_stage, occurred_at, metadata)

orchestrator/src/server/services/ghostwriter.test.ts

@@ -356,4 +356,23 @@ describe("ghostwriter service", () => {
     expect(result).toEqual({ cancelled: false, alreadyFinished: true });
     expect(mocks.repo.completeRun).not.toHaveBeenCalled();
   });
+
+  it("maps createRun unique constraint races to conflict", async () => {
+    mocks.repo.createMessage.mockResolvedValue(baseUserMessage);
+    mocks.repo.createRun.mockRejectedValue(
+      new Error(
+        "UNIQUE constraint failed: job_chat_runs.thread_id (idx_job_chat_runs_thread_running_unique)",
+      ),
+    );
+
+    await expect(
+      sendMessageForJob({
+        jobId: "job-1",
+        content: "hello",
+      }),
+    ).rejects.toMatchObject({
+      code: "CONFLICT",
+      status: 409,
+    });
+  });
 });

orchestrator/src/server/services/ghostwriter.ts

@@ -1,5 +1,6 @@
 import { logger } from "@infra/logger";
 import { getRequestId } from "@infra/request-context";
+import type { JobChatMessage, JobChatRun } from "@shared/types";
 import {
   badRequest,
   conflict,
@@ -52,6 +53,14 @@ function chunkText(value: string, maxChunk = 60): string[] {
   return chunks;
 }
 
+function isRunningRunUniqueConstraintError(error: unknown): boolean {
+  const message = error instanceof Error ? error.message : String(error);
+  return (
+    message.includes("idx_job_chat_runs_thread_running_unique") ||
+    message.includes("UNIQUE constraint failed: job_chat_runs.thread_id")
+  );
+}
+
 async function resolveLlmRuntimeSettings(): Promise<LlmRuntimeSettings> {
   const overrides = await settingsRepo.getAllSettings();
 
@@ -202,23 +211,41 @@ async function runAssistantReply(
 
   const requestId = getRequestId() ?? "unknown";
 
-  const assistantMessage = await jobChatRepo.createMessage({
-    threadId: options.threadId,
-    jobId: options.jobId,
-    role: "assistant",
-    content: "",
-    status: "partial",
-    version: options.version ?? 1,
-    replacesMessageId: options.replaceMessageId ?? null,
-  });
+  let run: JobChatRun;
+  try {
+    run = await jobChatRepo.createRun({
+      threadId: options.threadId,
+      jobId: options.jobId,
+      model: llmConfig.model,
+      provider: llmConfig.provider,
+      requestId,
+    });
+  } catch (error) {
+    if (isRunningRunUniqueConstraintError(error)) {
+      throw conflict("A chat generation is already running for this thread");
+    }
+    throw error;
+  }
 
-  const run = await jobChatRepo.createRun({
-    threadId: options.threadId,
-    jobId: options.jobId,
-    model: llmConfig.model,
-    provider: llmConfig.provider,
-    requestId,
-  });
+  let assistantMessage: JobChatMessage;
+  try {
+    assistantMessage = await jobChatRepo.createMessage({
+      threadId: options.threadId,
+      jobId: options.jobId,
+      role: "assistant",
+      content: "",
+      status: "partial",
+      version: options.version ?? 1,
+      replacesMessageId: options.replaceMessageId ?? null,
+    });
+  } catch (error) {
+    await jobChatRepo.completeRun(run.id, {
+      status: "failed",
+      errorCode: "INTERNAL_ERROR",
+      errorMessage: "Failed to create assistant message",
+    });
+    throw error;
+  }
 
   const controller = new AbortController();
   abortControllers.set(run.id, controller);