From 8a4224c1164234ade89d5f424f5d5549cadebd1b Mon Sep 17 00:00:00 2001
From: Tyagiquamar <mohdquamartyagi@gmail.com>
Date: Wed, 9 Sep 2026 23:59:36 +0530
Subject: [PATCH] Skip the Postgres replication-byte recorder in
 test-connection mode.

TEST_CONNECTION does not register DATA_REPLICATED_BYTES, so installing the jpgwire recorder made the CLI fail before the connection check ran.
---
 ...kip-test-connection-replication-metrics.md |  5 +++
 .../src/module/PostgresModule.ts              |  2 +-
 .../test/src/metrics_recorder.test.ts         | 40 +++++++++++++++++++
 3 files changed, 46 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/skip-test-connection-replication-metrics.md
 create mode 100644 modules/module-postgres/test/src/metrics_recorder.test.ts

diff --git a/.changeset/skip-test-connection-replication-metrics.md b/.changeset/skip-test-connection-replication-metrics.md
new file mode 100644
index 000000000..4406c5884
--- /dev/null
+++ b/.changeset/skip-test-connection-replication-metrics.md
@@ -0,0 +1,5 @@
+---
+'@powersync/service-module-postgres': patch
+---
+
+Skip the PostgreSQL replication-byte metrics recorder in `test-connection` mode so the command can run without `DATA_REPLICATED_BYTES`.
diff --git a/modules/module-postgres/src/module/PostgresModule.ts b/modules/module-postgres/src/module/PostgresModule.ts
index 3a3bfb2ec..101415230 100644
--- a/modules/module-postgres/src/module/PostgresModule.ts
+++ b/modules/module-postgres/src/module/PostgresModule.ts
@@ -31,7 +31,7 @@ export class PostgresModule extends replication.ReplicationModule<types.Postgres
 
   async onInitialized(context: system.ServiceContextContainer): Promise<void> {
     // Record replicated bytes using global jpgwire metrics. Only registered if this module is replicating
-    if (context.replicationEngine) {
+    if (context.replicationEngine && context.serviceMode !== system.ServiceContextMode.TEST_CONNECTION) {
       jpgwire.setMetricsRecorder({
         addBytesRead(bytes) {
           context.metricsEngine.getCounter(ReplicationMetric.DATA_REPLICATED_BYTES).add(bytes);
diff --git a/modules/module-postgres/test/src/metrics_recorder.test.ts b/modules/module-postgres/test/src/metrics_recorder.test.ts
new file mode 100644
index 000000000..22f75eccc
--- /dev/null
+++ b/modules/module-postgres/test/src/metrics_recorder.test.ts
@@ -0,0 +1,40 @@
+import { system } from '@powersync/service-core';
+import * as jpgwire from '@powersync/service-jpgwire';
+import { afterEach, describe, expect, it, vi } from 'vitest';
+import { PostgresModule } from '../../src/module/PostgresModule.js';
+
+describe('PostgresModule metrics recorder', () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it('does not install a jpgwire recorder in TEST_CONNECTION mode', async () => {
+    const spy = vi.spyOn(jpgwire, 'setMetricsRecorder');
+    const mod = new PostgresModule();
+    await mod.onInitialized({
+      replicationEngine: {},
+      serviceMode: system.ServiceContextMode.TEST_CONNECTION,
+      metricsEngine: {
+        getCounter() {
+          throw new Error('DATA_REPLICATED_BYTES should not be read in test-connection');
+        }
+      }
+    } as unknown as system.ServiceContextContainer);
+
+    expect(spy).not.toHaveBeenCalled();
+  });
+
+  it('installs a jpgwire recorder when replication metrics are available', async () => {
+    const spy = vi.spyOn(jpgwire, 'setMetricsRecorder');
+    const mod = new PostgresModule();
+    await mod.onInitialized({
+      replicationEngine: {},
+      serviceMode: system.ServiceContextMode.UNIFIED,
+      metricsEngine: {
+        getCounter: () => ({ add() {} })
+      }
+    } as unknown as system.ServiceContextContainer);
+
+    expect(spy).toHaveBeenCalledTimes(1);
+  });
+});