Add Config.Copy() in pgx and pgxpool packages. Conn.Config() and Pool.Config() return copy of the original config.

pgxpool/pool_test.go

@@ -28,7 +28,7 @@ func TestConnectConfig(t *testing.T) {
 	require.NoError(t, err)
 	pool, err := pgxpool.ConnectConfig(context.Background(), config)
 	require.NoError(t, err)
-	assert.Equal(t, config, pool.Config())
+	assertConfigsEqual(t, config, pool.Config(), "Pool.Config() returns original config")
 	pool.Close()
 }
 
@@ -78,6 +78,28 @@ func TestConnectConfigRequiresConnConfigFromParseConfig(t *testing.T) {
 	require.PanicsWithValue(t, "config must be created by ParseConfig", func() { pgxpool.ConnectConfig(context.Background(), config) })
 }
 
+func TestConfigCopyReturnsEqualConfig(t *testing.T) {
+	connString := "postgres://jack:secret@localhost:5432/mydb?application_name=pgxtest&search_path=myschema&connect_timeout=5"
+	original, err := pgxpool.ParseConfig(connString)
+	require.NoError(t, err)
+
+	copied := original.Copy()
+
+	assertConfigsEqual(t, original, copied, t.Name())
+}
+
+func TestConfigCopyCanBeUsedToConnect(t *testing.T) {
+	connString := os.Getenv("PGX_TEST_DATABASE")
+	original, err := pgxpool.ParseConfig(connString)
+	require.NoError(t, err)
+
+	copied := original.Copy()
+	assert.NotPanics(t, func() {
+		_, err = pgxpool.ConnectConfig(context.Background(), copied)
+	})
+	assert.NoError(t, err)
+}
+
 func TestPoolAcquireAndConnRelease(t *testing.T) {
 	t.Parallel()