add unwrap on json convert and test

Author: elianddb

enginetest/queries/json_scripts.go

@@ -15,13 +15,35 @@
 package queries
 
 import (
+	"github.com/dolthub/go-mysql-server/sql/plan"
 	"github.com/dolthub/vitess/go/vt/sqlparser"
 
 	"github.com/dolthub/go-mysql-server/sql"
 	"github.com/dolthub/go-mysql-server/sql/types"
 )
 
 var JsonScripts = []ScriptTest{
+	{
+		Name: "TextStorage converts to JSON when using dolt wrapper",
+		SetUpScript: []string{
+			"CREATE TABLE pages (id INT PRIMARY KEY, text_col TEXT, text_json JSON)",
+			"INSERT INTO pages VALUES (1, '{\"message\":\"hello\"}', NULL)",
+		},
+		Assertions: []ScriptTestAssertion{
+			{
+				Query: "UPDATE pages SET text_json = text_col",
+				Expected: []sql.Row{
+					{types.OkResult{RowsAffected: 1, Info: plan.UpdateInfo{Matched: 1, Updated: 1}}},
+				},
+			},
+			{
+				Query: "SELECT text_json FROM pages",
+				Expected: []sql.Row{
+					{types.MustJSON("{\"message\":\"hello\"}")},
+				},
+			},
+		},
+	},
 	{
 		Name: "json_type scripts",
 		Assertions: []ScriptTestAssertion{

sql/types/json.go

@@ -68,6 +68,21 @@ func (t JsonType) Convert(c context.Context, v interface{}) (doc interface{}, in
 		if err != nil {
 			return nil, sql.OutOfRange, sql.ErrInvalidJson.New(err.Error())
 		}
+	// Text values may be stored in wrappers (e.g. Dolt's TextStorage), so unwrap to the raw string before decoding.
+	case sql.StringWrapper:
+		str, err := v.Unwrap(c)
+		if err != nil {
+			return nil, sql.OutOfRange, err
+		}
+		charsetMaxLength := sql.Collation_Default.CharacterSet().MaxLength()
+		length := int64(len(str)) * charsetMaxLength
+		if length > MaxJsonFieldByteLength {
+			return nil, sql.InRange, ErrLengthTooLarge.New(length, MaxJsonFieldByteLength)
+		}
+		err = json.Unmarshal([]byte(str), &doc)
+		if err != nil {
+			return nil, sql.OutOfRange, sql.ErrInvalidJson.New(err.Error())
+		}
 	case int8:
 		return JSONDocument{Val: int64(v)}, sql.InRange, nil
 	case int16:

sql/types/jsontests/json_test.go

@@ -28,6 +28,34 @@ import (
 	"github.com/dolthub/go-mysql-server/sql/types"
 )
 
+type mockStringWrapper struct {
+	val string
+}
+
+func (m mockStringWrapper) Unwrap(ctx context.Context) (string, error) {
+	return m.val, nil
+}
+
+func (m mockStringWrapper) UnwrapAny(ctx context.Context) (interface{}, error) {
+	return m.val, nil
+}
+
+func (m mockStringWrapper) IsExactLength() bool {
+	return false
+}
+
+func (m mockStringWrapper) MaxByteLength() int64 {
+	return int64(len(m.val))
+}
+
+func (m mockStringWrapper) Compare(ctx context.Context, other interface{}) (int, bool, error) {
+	return 0, false, nil
+}
+
+func (m mockStringWrapper) Hash() interface{} {
+	return m.val
+}
+
 func TestJsonCompare(t *testing.T) {
 	RunJsonCompareTests(t, JsonCompareTests, func(t *testing.T, left, right interface{}) (interface{}, interface{}) {
 		return ConvertToJson(t, left), ConvertToJson(t, right)
@@ -58,6 +86,7 @@ func TestJsonConvert(t *testing.T) {
 		{types.MustJSON(`{"field":"test"}`), types.MustJSON(`{"field":"test"}`), false},
 		{[]string{}, types.MustJSON(`[]`), false},
 		{[]string{`555-555-5555`}, types.MustJSON(`["555-555-5555"]`), false},
+		{mockStringWrapper{val: `{"c": 1}`}, types.MustJSON(`{"c":1}`), false},
 	}
 
 	for _, test := range tests {