From 7e80ab274efa8f3c751216d671d27b2d56d98117 Mon Sep 17 00:00:00 2001
From: Yarchik <spoko.dev@gmail.com>
Date: Tue, 23 Jun 2026 17:04:42 +0100
Subject: [PATCH] fix(pg-connection-string): strip brackets from IPv6 host

The WHATWG URL parser keeps the square brackets around an IPv6 literal,
so parse('postgresql://[::1]:5432/db').host returned '[::1]'. libpq
stores the address without the brackets, and consumers pass config.host
straight to net.connect / dns.lookup, which treat '[::1]' as a hostname
and fail with ENOTFOUND. Strip the brackets so IPv6 connection strings
resolve to the bare address.
---
 packages/pg-connection-string/index.js      | 5 ++++-
 packages/pg-connection-string/test/parse.ts | 7 +++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/packages/pg-connection-string/index.js b/packages/pg-connection-string/index.js
index 7ee302976..56423d124 100644
--- a/packages/pg-connection-string/index.js
+++ b/packages/pg-connection-string/index.js
@@ -50,7 +50,10 @@ function parse(str, options = {}) {
     config.client_encoding = result.searchParams.get('encoding')
     return config
   }
-  const hostname = dummyHost ? '' : result.hostname
+  // The WHATWG URL parser keeps the square brackets around an IPv6 literal
+  // (e.g. [::1]); strip them so config.host is a bare address that libpq, and
+  // node's net.connect / dns.lookup, can use directly.
+  const hostname = (dummyHost ? '' : result.hostname).replace(/^\[(.+)\]$/, '$1')
   if (!config.host) {
     // Only set the host if there is no equivalent query param.
     config.host = decodeURIComponent(hostname)
diff --git a/packages/pg-connection-string/test/parse.ts b/packages/pg-connection-string/test/parse.ts
index c2a537581..59d8ef77c 100644
--- a/packages/pg-connection-string/test/parse.ts
+++ b/packages/pg-connection-string/test/parse.ts
@@ -111,6 +111,13 @@ describe('parse', function () {
     subject.host?.should.equal('localhost')
   })
 
+  it('strips the brackets from an IPv6 host', function () {
+    const subject = parse('postgres://user:pw@[2001:db8::1]:5432/mydb')
+    subject.host?.should.equal('2001:db8::1')
+    subject.port?.should.equal('5432')
+    parse('postgres://[::1]/db').host?.should.equal('::1')
+  })
+
   it('url is properly encoded', function () {
     const encoded = 'pg://bi%25na%25%25ry%20:s%40f%23@localhost/%20u%2520rl'
     const subject = parse(encoded)