json: Fix quoting JSON keys (#14066)

Signed-off-by: Dirkjan Bussink <[email protected]>

go/mysql/json/marshal.go

@@ -42,9 +42,9 @@ func (v *Value) marshalSQLInternal(top bool, dst []byte) []byte {
 			if i != 0 {
 				dst = append(dst, ", "...)
 			}
-			dst = append(dst, "_utf8mb4'"...)
-			dst = append(dst, vv.k...)
-			dst = append(dst, "', "...)
+			dst = append(dst, "_utf8mb4"...)
+			dst = append(dst, sqltypes.EncodeStringSQL(vv.k)...)
+			dst = append(dst, ", "...)
 			dst = vv.v.marshalSQLInternal(false, dst)
 		}
 		dst = append(dst, ')')

go/mysql/json/marshal_test.go

@@ -0,0 +1,57 @@
+/*
+Copyright 2023 The Vitess Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package json
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestMarshalSQLTo(t *testing.T) {
+	testcases := []struct {
+		input    string
+		expected string
+	}{
+		{
+			input:    "null",
+			expected: "CAST(_utf8mb4'null' as JSON)",
+		},
+		{
+			input:    `{}`,
+			expected: `JSON_OBJECT()`,
+		},
+		{
+			input:    `{"a": 1}`,
+			expected: `JSON_OBJECT(_utf8mb4'a', 1)`,
+		},
+		{
+			input:    `{"key with ' in it": []}`,
+			expected: `JSON_OBJECT(_utf8mb4'key with \' in it', JSON_ARRAY())`,
+		},
+	}
+	for _, tc := range testcases {
+		t.Run(tc.input, func(t *testing.T) {
+			var p Parser
+
+			v, err := p.Parse(tc.input)
+			require.NoError(t, err)
+			buf := v.MarshalSQLTo(nil)
+			require.Equal(t, tc.expected, string(buf))
+		})
+	}
+}