From 27a71009d718f9e33688376967e332dcac7790d7 Mon Sep 17 00:00:00 2001
From: Malthe Borch <mborch@gmail.com>
Date: Wed, 19 Jun 2024 07:52:14 +0200
Subject: [PATCH] Add back 'end' event and fix graceful shutdown error handling

---
 CHANGES.md          |  5 +++++
 src/client.ts       | 30 ++++++++++++++++++------------
 test/client.test.ts |  3 +++
 3 files changed, 26 insertions(+), 12 deletions(-)

diff --git a/CHANGES.md b/CHANGES.md
index cb3f7ef..c713964 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,5 +1,10 @@
 In next release ...
 
+- Added "end" event which was removed in v1.8.0.
+
+- The `end` method now correctly throws an error if a network error
+  occurred during the resulting protocol traffic.
+
 ## v2.0.3 (2024-06-15)
 
 - Fix issue where larger results would sometimes have duplicates (#122).
diff --git a/src/client.ts b/src/client.ts
index 78e164b..41e8b23 100644
--- a/src/client.ts
+++ b/src/client.ts
@@ -142,15 +142,17 @@ interface PreFlightQueue {
 
 const DEFAULTS = new Defaults(env as Record<string, string>);
 
-export type EventMap<
-    T = {
-        error: DatabaseError;
-        notice: ClientNotice;
-        notification: Notification;
-    },
-> = {
-    [K in keyof T]: [T[K]];
-};
+
+export interface EventMap {
+    /** The connection has ended, possibly due to a network error. */
+    end: [NodeJS.ErrnoException | null];
+    /** A database error has occurred. */
+    error: [DatabaseError];
+    /** A client notice (typically a warning) has been received. */
+    notice: [ClientNotice];
+    /** A client notification has been received. */
+    notification: [Notification];
+}
 
 type Resolve<T> = (value?: T) => void;
 
@@ -209,6 +211,7 @@ export class ClientImpl {
 
         this.stream.on('close', () => {
             this.closed = true;
+            this.events.emit('end', null);
             this.ending?.();
         });
 
@@ -233,10 +236,12 @@ export class ClientImpl {
             } else {
                 // Don't raise ECONNRESET errors - they can & should be
                 // ignored during disconnect.
+                if (error.errno === constants.errno.ECONNRESET) return;
+
                 if (this.ending) {
-                    if (error.errno === constants.errno.ECONNRESET) return;
-                    this.ending();
+                    this.ending(error);
                 }
+                this.events.emit('end', error);
             }
         });
 
@@ -286,7 +291,8 @@ export class ClientImpl {
 
             const abort = (error: Error) => {
                 this.handleError(error);
-                this.connecting?.(error);
+                if (!this.connecting) throw error;
+                this.connecting(error);
             };
 
             const startup = (stream?: Socket) => {
diff --git a/test/client.test.ts b/test/client.test.ts
index 78d9e7d..cec55fa 100644
--- a/test/client.test.ts
+++ b/test/client.test.ts
@@ -287,9 +287,12 @@ describe('Query', () => {
             idleInTransactionSessionTimeout: 500,
         });
         const errors: string[] = [];
+        let error: NodeJS.ErrnoException | null = null;
+        client.on('end', (isError) => error = isError);
         client.on('error', (error) => errors.push(error.code));
         await new Promise((resolve) => setTimeout(resolve, 625));
         equal(client.closed, true);
+        equal(error, null);
         deepEqual(errors, ['57P05']);
     });