Fix prepare failure

pgconn/pgconn.go

@@ -438,6 +438,8 @@ func (pgConn *PgConn) Prepare(ctx context.Context, name, sql string, paramOIDs [
 
 	psd := &PreparedStatementDescription{Name: name, SQL: sql}
 
+	var parseErr error
+
 readloop:
 	for {
 		msg, err := pgConn.ReceiveMessage()
@@ -454,14 +456,17 @@ readloop:
 			psd.Fields = make([]pgproto3.FieldDescription, len(msg.Fields))
 			copy(psd.Fields, msg.Fields)
 		case *pgproto3.ErrorResponse:
-			go pgConn.recoverFromTimeout()
+			parseErr = errorResponseToPgError(msg)
-			return nil, errorResponseToPgError(msg)
 		case *pgproto3.ReadyForQuery:
 			break readloop
 		}
 	}
 
 	<-pgConn.controller
+
+	if parseErr != nil {
+		return nil, parseErr
+	}
 	return psd, nil
 }
 

pgconn/pgconn_test.go

@@ -235,6 +235,20 @@ func TestConnectWithAfterConnectTargetSessionAttrsReadWrite(t *testing.T) {
 	}
 }
 
+func TestConnPrepareFailure(t *testing.T) {
+	t.Parallel()
+
+	pgConn, err := pgconn.Connect(context.Background(), os.Getenv("PGX_TEST_DATABASE"))
+	require.Nil(t, err)
+	defer closeConn(t, pgConn)
+
+	psd, err := pgConn.Prepare(context.Background(), "ps1", "SYNTAX ERROR", nil)
+	require.Nil(t, psd)
+	require.NotNil(t, err)
+
+	ensureConnValid(t, pgConn)
+}
+
 func TestConnExec(t *testing.T) {
 	t.Parallel()