From 3b1e24d2133fcc437880eaebc77bb92a6599f235 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Do=C4=9Fan=20Can=20Bak=C4=B1r?=
 <dogancanbakir@protonmail.com>
Date: Thu, 7 Sep 2023 08:34:29 +0000
Subject: [PATCH 1/2] add TryJoinHostPort func

---
 net/net.go      | 16 ++++++++++++++
 net/net_test.go | 57 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 73 insertions(+)
 create mode 100644 net/net.go
 create mode 100644 net/net_test.go

diff --git a/net/net.go b/net/net.go
new file mode 100644
index 0000000..a3c4eeb
--- /dev/null
+++ b/net/net.go
@@ -0,0 +1,16 @@
+package netutil
+
+import "net"
+
+// TryJoinHostPort joins host and port. If port is empty, it returns host and an error.
+func TryJoinHostPort(host, port string) (string, error) {
+	if host == "" {
+		return "", &net.AddrError{Err: "missing host", Addr: host}
+	}
+
+	if port == "" {
+		return host, &net.AddrError{Err: "missing port", Addr: host}
+	}
+
+	return net.JoinHostPort(host, port), nil
+}
diff --git a/net/net_test.go b/net/net_test.go
new file mode 100644
index 0000000..377f0c7
--- /dev/null
+++ b/net/net_test.go
@@ -0,0 +1,57 @@
+package netutil
+
+import (
+	"testing"
+)
+
+func TestTryJoinHostPort(t *testing.T) {
+	tests := []struct {
+		name    string
+		host    string
+		port    string
+		want    string
+		wantErr bool
+	}{
+		{
+			name:    "both host and port provided",
+			host:    "localhost",
+			port:    "8080",
+			want:    "localhost:8080",
+			wantErr: false,
+		},
+		{
+			name:    "empty host",
+			host:    "",
+			port:    "8080",
+			want:    "",
+			wantErr: true,
+		},
+		{
+			name:    "empty port",
+			host:    "localhost",
+			port:    "",
+			want:    "localhost",
+			wantErr: true,
+		},
+		{
+			name:    "both host and port empty",
+			host:    "",
+			port:    "",
+			want:    "",
+			wantErr: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := TryJoinHostPort(tt.host, tt.port)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("TryJoinHostPort() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if got != tt.want {
+				t.Errorf("TryJoinHostPort() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

From 48138972b9bf8e13fed39acd6acec5163ae68edc Mon Sep 17 00:00:00 2001
From: mzack <marco.rivoli.nvh@gmail.com>
Date: Mon, 11 Sep 2023 09:38:33 +0200
Subject: [PATCH 2/2] using custom error

---
 net/net.go | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/net/net.go b/net/net.go
index a3c4eeb..a3ec78b 100644
--- a/net/net.go
+++ b/net/net.go
@@ -1,6 +1,11 @@
 package netutil
 
-import "net"
+import (
+	"errors"
+	"net"
+)
+
+var ErrMissingPort = errors.New("missing port")
 
 // TryJoinHostPort joins host and port. If port is empty, it returns host and an error.
 func TryJoinHostPort(host, port string) (string, error) {
@@ -9,7 +14,7 @@ func TryJoinHostPort(host, port string) (string, error) {
 	}
 
 	if port == "" {
-		return host, &net.AddrError{Err: "missing port", Addr: host}
+		return host, ErrMissingPort
 	}
 
 	return net.JoinHostPort(host, port), nil