fix: set allowExitOnIdle on source pool to prevent hang

src/sql/postgresjs.exit.test.ts

@@ -0,0 +1,80 @@
+import { test, expect } from "vitest";
+import { PostgreSqlContainer } from "@testcontainers/postgresql";
+import { execFile } from "node:child_process";
+
+function runScript(
+  script: string,
+): Promise<{ exitCode: number; timedOut: boolean }> {
+  return new Promise((resolve) => {
+    const child = execFile(
+      "node",
+      ["--import=tsx", "--input-type=module", "-e", script],
+      { timeout: 5_000 },
+      (error) => {
+        resolve({
+          exitCode: error ? Number(error.code ?? 1) : 0,
+          timedOut: error?.killed === true,
+        });
+      },
+    );
+    // Pipe to a pipe (not inherit) to mimic CI where SIGPIPE can occur
+    child.stdout?.resume();
+    child.stderr?.resume();
+  });
+}
+
+/**
+ * Verifies that a process with an idle source pool connection exits
+ * naturally without hanging. Without allowExitOnIdle, pg-pool keeps
+ * idle connections ref'd, which blocks Node from exiting.
+ */
+test("process exits without hanging when source pool has idle connections", async () => {
+  const pg = await new PostgreSqlContainer("postgres:17").start();
+
+  const script = `
+    import { connectToSource } from "./src/sql/postgresjs.ts";
+    import { Connectable } from "./src/sync/connectable.ts";
+    const db = connectToSource(Connectable.fromString("${pg.getConnectionUri()}"));
+    await db.exec("SELECT 1");
+    // Intentionally do NOT call db.close() — idle connection stays in pool.
+    // With allowExitOnIdle, the process should still exit promptly.
+    // Without it, the idle connection's ref'd socket blocks exit.
+  `;
+
+  try {
+    const { exitCode, timedOut } = await runScript(script);
+
+    expect(timedOut, "process should not hang on idle pool connections").toBe(
+      false,
+    );
+    expect(exitCode, "process should exit 0, not SIGPIPE (13)").toBe(0);
+  } finally {
+    await pg.stop();
+  }
+});
+
+/**
+ * Verifies that a process exits cleanly (code 0) after explicitly
+ * closing the source pool. This guards against SIGPIPE (exit 13)
+ * caused by process.exit() killing I/O mid-flush.
+ */
+test("process exits with code 0 after explicit pool close", async () => {
+  const pg = await new PostgreSqlContainer("postgres:17").start();
+
+  const script = `
+    import { connectToSource } from "./src/sql/postgresjs.ts";
+    import { Connectable } from "./src/sync/connectable.ts";
+    const db = connectToSource(Connectable.fromString("${pg.getConnectionUri()}"));
+    await db.exec("SELECT 1");
+    await db.close();
+  `;
+
+  try {
+    const { exitCode, timedOut } = await runScript(script);
+
+    expect(timedOut, "process should not hang after pool.end()").toBe(false);
+    expect(exitCode, "process should exit 0, not SIGPIPE (13)").toBe(0);
+  } finally {
+    await pg.stop();
+  }
+});

src/sql/postgresjs.ts

@@ -55,6 +55,7 @@ export function connectToSource(
   const config: PoolConfig = {
     max: 20,
     idleTimeoutMillis: DEFAULT_IDLE_TIMEOUT_MS,
+    allowExitOnIdle: true,
   };
 
   return connect(connectable, config);