feat(client): add table and column name length validation

Author: puzpuzpuz

sender.go

@@ -48,6 +48,8 @@ import (
 // chars found in table or column name.
 var ErrInvalidMsg = errors.New("invalid message")
 
+const fsFileNameLimit = 127
+
 type tlsMode int64
 
 const (
@@ -375,6 +377,11 @@ func (s *LineSender) writeTableName(str string) error {
 	if str == "" {
 		return fmt.Errorf("table name cannot be empty: %w", ErrInvalidMsg)
 	}
+	// We use string length in bytes as an approximation. That's to
+	// avoid calculating the number of runes.
+	if len(str) > fsFileNameLimit {
+		return fmt.Errorf("table name length is too large: %w", ErrInvalidMsg)
+	}
 	// Since we're interested in ASCII chars, it's fine to iterate
 	// through bytes instead of runes.
 	for i := 0; i < len(str); i++ {
@@ -470,6 +477,11 @@ func (s *LineSender) writeColumnName(str string) error {
 	if str == "" {
 		return fmt.Errorf("column name cannot be empty: %w", ErrInvalidMsg)
 	}
+	// We use string length in bytes as an approximation. That's to
+	// avoid calculating the number of runes.
+	if len(str) > fsFileNameLimit {
+		return fmt.Errorf("column name length is too large: %w", ErrInvalidMsg)
+	}
 	// Since we're interested in ASCII chars, it's fine to iterate
 	// through bytes instead of runes.
 	for i := 0; i < len(str); i++ {

sender_test.go

@@ -193,6 +193,49 @@ func TestFloat64Serialization(t *testing.T) {
 	}
 }
 
+func TestErrorOnLengthyNames(t *testing.T) {
+	ctx := context.Background()
+
+	lengthyStr := strings.Repeat("a", 128)
+
+	testCases := []struct {
+		name           string
+		writerFn       writerFn
+		expectedErrMsg string
+	}{
+		{
+			"lengthy table name",
+			func(s *qdb.LineSender) error {
+				return s.Table(lengthyStr).StringColumn("str_col", "foo").AtNow(ctx)
+			},
+			"table name length is too large",
+		},
+		{
+			"lengthy column name",
+			func(s *qdb.LineSender) error {
+				return s.Table(testTable).StringColumn(lengthyStr, "foo").AtNow(ctx)
+			},
+			"column name length is too large",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			srv, err := newTestServer(readAndDiscard)
+			assert.NoError(t, err)
+
+			sender, err := qdb.NewLineSender(ctx, qdb.WithAddress(srv.addr))
+			assert.NoError(t, err)
+
+			err = tc.writerFn(sender)
+			assert.ErrorContains(t, err, tc.expectedErrMsg)
+
+			sender.Close()
+			srv.close()
+		})
+	}
+}
+
 func TestErrorOnMissingTableCall(t *testing.T) {
 	ctx := context.Background()