From 5656f830d617cb9a4330c0ca1e978b018061e085 Mon Sep 17 00:00:00 2001
From: Charmander <~@charmander.me>
Date: Wed, 13 May 2026 22:01:31 -0700
Subject: [PATCH 1/3] test: unintended listener after no-op `Client#end`
 callback

---
 packages/pg/test/integration/client/api-tests.js | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/packages/pg/test/integration/client/api-tests.js b/packages/pg/test/integration/client/api-tests.js
index ab7ad6db8..2b0c3f85b 100644
--- a/packages/pg/test/integration/client/api-tests.js
+++ b/packages/pg/test/integration/client/api-tests.js
@@ -230,6 +230,21 @@ suite.test('callback is fired once and only once', function (done) {
   )
 })
 
+suite.test('no-op Client#end callback is called exactly once', (done) => {
+  const client = new helper.Client()
+  let called = false
+
+  client.end(() => {
+    assert(!called)
+    called = true
+
+    client.connect((err) => {
+      assert.ifError(err)
+      client.end(done)
+    })
+  })
+})
+
 suite.test('can provide callback and config object', function (done) {
   const pool = new pg.Pool()
   pool.connect(

From 7a97d7e943e3f2c7801e1cd78e0ed8c3165ac3b2 Mon Sep 17 00:00:00 2001
From: Charmander <~@charmander.me>
Date: Wed, 13 May 2026 22:02:46 -0700
Subject: [PATCH 2/3] fix: `Client#end` callback being called multiple times
 when first is no-op

(and unwanted retained listener even when not called multiple times)
---
 packages/pg/lib/client.js | 1 +
 1 file changed, 1 insertion(+)

diff --git a/packages/pg/lib/client.js b/packages/pg/lib/client.js
index 3bfffc7d2..3525cf5ac 100644
--- a/packages/pg/lib/client.js
+++ b/packages/pg/lib/client.js
@@ -716,6 +716,7 @@ class Client extends EventEmitter {
     if (!this.connection._connecting || this._ended) {
       if (cb) {
         cb()
+        return
       } else {
         return this._Promise.resolve()
       }

From 6f543f4a65134b0dce466158bb2fe60ed6eabaa6 Mon Sep 17 00:00:00 2001
From: Charmander <~@charmander.me>
Date: Wed, 13 May 2026 22:16:41 -0700
Subject: [PATCH 3/3] fix: Prevent multiple callbacks in pg/native
 `Client#end`, and align pre-connect behaviour closer to pg
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

As usual, the native client is extra full of bugs and inconsistencies, so this is just “good enough”.
---
 packages/pg/lib/native/client.js | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/packages/pg/lib/native/client.js b/packages/pg/lib/native/client.js
index 6df471b83..fa17d9f65 100644
--- a/packages/pg/lib/native/client.js
+++ b/packages/pg/lib/native/client.js
@@ -249,8 +249,10 @@ Client.prototype.end = function (cb) {
 
   this._ending = true
 
-  if (!this._connected) {
-    this.once('connect', this.end.bind(this, cb))
+  if (this._connecting && !this._connected) {
+    this.once('connect', () => {
+      this.end(() => {})
+    })
   }
   let result
   if (!cb) {