fix(core): join running embedded Postgres correctly

Read the live port from PostgreSQL's actual postmaster.pid field so extension TaskStore boot reuses the existing server instead of wedging on a colliding start.

.changeset/fix-extension-taskstore-postmaster-port.md

@@ -0,0 +1,7 @@
+---
+"@runfusion/fusion": patch
+---
+
+summary: Prevent fn_task_show timeouts when another Fusion process already owns embedded PostgreSQL.
+category: fix
+dev: Reads the port from PostgreSQL's actual postmaster.pid line 4 field before joining the running instance.

packages/core/src/__tests__/postgres/embedded-lifecycle.test.ts

@@ -808,7 +808,7 @@ describe("embedded-lifecycle: startup race (cross-process)", () => {
       async start() {
         writeFileSync(
           join(dataDir, "postmaster.pid"),
-          ["12345", dataDir, "/tmp", "localhost", "55440", "5432101", String(Date.now())].join("\n") + "\n",
+          ["12345", dataDir, String(Date.now()), "55440", "/tmp", "localhost", "5432101", "ready"].join("\n") + "\n",
         );
         throw new Error('lock file "postmaster.pid" already exists');
       }
@@ -864,7 +864,7 @@ describe("embedded-lifecycle: startup race only joins on a lock collision", () =
         // A postmaster.pid exists (ours, or a racer's) but the failure is NOT a lock collision.
         writeFileSync(
           join(dataDir, "postmaster.pid"),
-          ["12345", dataDir, "/tmp", "localhost", "55442", "5432101", String(Date.now())].join("\n") + "\n",
+          ["12345", dataDir, String(Date.now()), "55442", "/tmp", "localhost", "5432101", "ready"].join("\n") + "\n",
         );
         throw new Error("could not start postgres: readiness poll timed out");
       }
@@ -891,7 +891,7 @@ describe("embedded-lifecycle: startup race only joins on a lock collision", () =
       async start() {
         writeFileSync(
           join(dataDir, "postmaster.pid"),
-          ["12345", dataDir, "/tmp", "localhost", "55444", "5432101", String(Date.now())].join("\n") + "\n",
+          ["12345", dataDir, String(Date.now()), "55444", "/tmp", "localhost", "5432101", "ready"].join("\n") + "\n",
         );
         throw new Error('lock file "postmaster.pid" already exists');
       }
@@ -918,7 +918,7 @@ describe("embedded-lifecycle: join-path database verify is best-effort", () => {
     // A port nothing is listening on: the verify's probe cannot succeed.
     writeFileSync(
       join(dataDir, "postmaster.pid"),
-      ["12345", dataDir, "/tmp", "localhost", "55441", "5432101", String(Date.now())].join("\n") + "\n",
+      ["12345", dataDir, String(Date.now()), "55441", "/tmp", "localhost", "5432101", "ready"].join("\n") + "\n",
     );
     const logLines: string[] = [];
 
@@ -1027,28 +1027,30 @@ describe("embedded-lifecycle: startup timeout (P1 #24)", () => {
 });
 
 describe("embedded-lifecycle: readPortFromPostmasterPid (P1 code-review fix)", () => {
-  it("reads the TCP port from line 5 (index 4) of postmaster.pid", () => {
+  it("reads the TCP port from PostgreSQL's real line 4 (index 3) postmaster.pid layout", () => {
     const dir = mkdtempSync(join(tmpdir(), "fusion-embedded-pid-"));
     try {
       const { writeFileSync } = require("node:fs");
       // Standard PostgreSQL postmaster.pid format:
       // Line 1: PID
       // Line 2: data directory
-      // Line 3: unix socket directory
+      // Line 3: postmaster start timestamp
-      // Line 4: listen address
+      // Line 4: port number
-      // Line 5: port number
+      // Line 5: unix socket directory
-      // Line 6: shared memory key
+      // Line 6: listen address
-      // Line 7: postmaster start timestamp
+      // Line 7: shared memory key and id
+      // Line 8: status
       writeFileSync(
         join(dir, "postmaster.pid"),
         [
           "12345",
           "/home/user/.fusion/embedded-postgres/default",
+          "1784361395",
+          "55432",
           "/tmp",
           "localhost",
-          "55432",
+          "18446744071752735336 19857409",
-          "5432101",
+          "ready",
-          String(Date.now()),
         ].join("\n") + "\n",
       );
 
@@ -1065,7 +1067,7 @@ describe("embedded-lifecycle: readPortFromPostmasterPid (P1 code-review fix)", (
       const { writeFileSync } = require("node:fs");
       writeFileSync(
         join(dir, "postmaster.pid"),
-        ["12345", "/data", "/tmp", "localhost", "not-a-port", "5432101"].join("\n") + "\n",
+        ["12345", "/data", "1784361395", "not-a-port", "/tmp", "localhost", "5432101", "ready"].join("\n") + "\n",
       );
       expect(readPortFromPostmasterPid(dir)).toBeNull();
     } finally {
@@ -1082,16 +1084,15 @@ describe("embedded-lifecycle: readPortFromPostmasterPid (P1 code-review fix)", (
     }
   });
 
-  it("does NOT read line 3 (index 2, socket dir) as the port", () => {
+  it("does NOT read line 3 (index 2, start timestamp) as the port", () => {
-    // Regression: the bug read lines[2] (socket dir) which is never the port.
+    // The start timestamp is numeric, so parsing the wrong adjacent line would
-    // If the socket dir happened to contain digits, parseInt would produce
+    // produce a plausible-looking but unusable port.
-    // a wrong port. This test ensures we skip past it.
     const dir = mkdtempSync(join(tmpdir(), "fusion-embedded-pid-"));
     try {
       const { writeFileSync } = require("node:fs");
       writeFileSync(
         join(dir, "postmaster.pid"),
-        ["12345", "/data", "/var/run/postgresql", "localhost", "5433", "5432101"].join("\n") + "\n",
+        ["12345", "/data", "1784361395", "5433", "/var/run/postgresql", "localhost", "5432101", "ready"].join("\n") + "\n",
       );
       const port = readPortFromPostmasterPid(dir);
       expect(port).toBe(5433);

packages/core/src/postgres/embedded-lifecycle.ts

@@ -927,16 +927,18 @@ const runningInstances = new Map<string, { port: number; database: string }>();
  * Read the port from a postmaster.pid file. The standard PostgreSQL format is:
  *   Line 1 (index 0): PID
  *   Line 2 (index 1): Data directory path
- *   Line 3 (index 2): Unix socket directory
+ *   Line 3 (index 2): Postmaster start timestamp
- *   Line 4 (index 3): Listen address (e.g. localhost or *)
+ *   Line 4 (index 3): Port number
- *   Line 5 (index 4): Port number
+ *   Line 5 (index 4): Unix socket directory
- *   Line 6 (index 5): Shared memory key
+ *   Line 6 (index 5): Listen address (e.g. localhost or *)
- *   Line 7 (index 6): Postmaster start timestamp
+ *   Line 7 (index 6): Shared memory key and id
+ *   Line 8 (index 7): Status
  *
  * FNXC:PostgresCutover 2026-06-27-14:30 (fix code-review P1):
- * Previously read line 3 (index 2, the socket dir) which is never a port
+ * The earlier correction still encoded the wrong field order and read line 5
- * number, so singleton detection via postmaster.pid ALWAYS failed. Fixed to
+ * (the socket directory). Read PostgreSQL's actual line 4 port field so a
- * read line 5 (index 4, the TCP port).
+ * second Fusion process joins the running postmaster instead of attempting a
+ * colliding start that can wedge extension TaskStore boot.
  *
  * Returns null if the file cannot be read or parsed.
  */
@@ -944,8 +946,8 @@ export function readPortFromPostmasterPid(dataDir: string): number | null {
   try {
     const content = readFileSync(join(dataDir, "postmaster.pid"), "utf-8");
     const lines = content.split("\n");
-    // Line 5 (index 4) is the TCP port in standard PostgreSQL postmaster.pid
+    // Line 4 (index 3) is the TCP port in standard PostgreSQL postmaster.pid.
-    const portStr = lines[4]?.trim();
+    const portStr = lines[3]?.trim();
     if (portStr) {
       const port = parseInt(portStr, 10);
       if (!isNaN(port) && port > 0) return port;