support json_valid() function

enginetest/queries/queries.go

@@ -8981,7 +8981,14 @@ var ErrorQueries = []QueryErrorTest{
 		Query:       "SELECT json_set() FROM dual;",
 		ExpectedErr: sql.ErrInvalidArgumentNumber,
 	},
-
+	{
+		Query: `SELECT JSON_VALID()`,
+		ExpectedErr: sql.ErrInvalidArgumentNumber,
+	},
+	{
+		Query: `SELECT JSON_VALID('{"a": 1}','[1]')`,
+		ExpectedErr: sql.ErrInvalidArgumentNumber,
+	},
 	// This gets an error "unable to cast "second row" of type string to int64"
 	// Should throw sql.ErrAmbiguousColumnInOrderBy
 	{

sql/expression/function/aggregation/json_agg.go

@@ -17,15 +17,10 @@ package aggregation
 import (
 	"fmt"
 
-	"gopkg.in/src-d/go-errors.v1"
-
 	"github.com/dolthub/go-mysql-server/sql"
 	"github.com/dolthub/go-mysql-server/sql/types"
 )
 
-// ErrUnsupportedJSONFunction is returned when a unsupported JSON function is called.
-var ErrUnsupportedJSONFunction = errors.NewKind("unsupported JSON function: %s")
-
 // JSON_OBJECTAGG(key, value) [over_clause]
 //
 // JSONObjectAgg Takes two column names or expressions as arguments, the first of these being used as a key and the

sql/expression/function/json/json_array_append.go

@@ -129,3 +129,8 @@ func (j JSONArrayAppend) FunctionName() string {
 func (j JSONArrayAppend) Description() string {
 	return "appends data to JSON document."
 }
+
+// IsUnsupported implements sql.UnsupportedFunctionStub
+func (j JSONArrayAppend) IsUnsupported() bool {
+	return false
+}

sql/expression/function/json/json_array_insert.go

@@ -131,3 +131,8 @@ func (j JSONArrayInsert) FunctionName() string {
 func (j JSONArrayInsert) Description() string {
 	return "inserts into JSON array."
 }
+
+// IsUnsupported implements sql.UnsupportedFunctionStub
+func (j JSONArrayInsert) IsUnsupported() bool {
+	return false
+}

sql/expression/function/json/json_contains.go

@@ -81,7 +81,7 @@ func (j *JSONContains) Description() string {
 
 // IsUnsupported implements sql.UnsupportedFunctionStub
 func (j JSONContains) IsUnsupported() bool {
-	return true
+	return false
 }
 
 func (j *JSONContains) Resolved() bool {

sql/expression/function/json/json_extract.go

@@ -151,3 +151,8 @@ func (j *JSONExtract) String() string {
 	}
 	return fmt.Sprintf("json_extract(%s)", strings.Join(parts, ", "))
 }
+
+// IsUnsupported implements sql.UnsupportedFunctionStub
+func (j JSONExtract) IsUnsupported() bool {
+	return false
+}

sql/expression/function/json/json_insert.go

@@ -134,3 +134,8 @@ func (j JSONInsert) FunctionName() string {
 func (j JSONInsert) Description() string {
 	return "inserts data into JSON document"
 }
+
+// IsUnsupported implements sql.UnsupportedFunctionStub
+func (j JSONInsert) IsUnsupported() bool {
+	return false
+}

sql/expression/function/json/json_object.go

@@ -53,11 +53,6 @@ func (j JSONObject) Description() string {
 	return "creates JSON object."
 }
 
-// IsUnsupported implements sql.UnsupportedFunctionStub
-func (j JSONObject) IsUnsupported() bool {
-	return true
-}
-
 func (j JSONObject) Resolved() bool {
 	for _, child := range j.Children() {
 		if child != nil && !child.Resolved() {

sql/expression/function/json/json_remove.go

@@ -129,3 +129,8 @@ func (j JSONRemove) Eval(ctx *sql.Context, row sql.Row) (interface{}, error) {
 	}
 	return doc, nil
 }
+
+// IsUnsupported implements sql.UnsupportedFunctionStub
+func (j JSONRemove) IsUnsupported() bool {
+	return false
+}

sql/expression/function/json/json_replace.go

@@ -129,3 +129,8 @@ func (j JSONReplace) FunctionName() string {
 func (j JSONReplace) Description() string {
 	return "replaces values in JSON document."
 }
+
+// IsUnsupported implements sql.UnsupportedFunctionStub
+func (j JSONReplace) IsUnsupported() bool {
+	return false
+}

sql/expression/function/json/json_set.go

@@ -138,3 +138,8 @@ func (j *JSONSet) Eval(ctx *sql.Context, row sql.Row) (interface{}, error) {
 
 	return doc, nil
 }
+
+// IsUnsupported implements sql.UnsupportedFunctionStub
+func (j JSONSet) IsUnsupported() bool {
+	return false
+}

sql/expression/function/json/json_unquote.go

@@ -51,7 +51,7 @@ func (js *JSONUnquote) Description() string {
 
 // IsUnsupported implements sql.UnsupportedFunctionStub
 func (js *JSONUnquote) IsUnsupported() bool {
-	return true
+	return false
 }
 
 func (js *JSONUnquote) String() string {

sql/expression/function/json/json_unsupported.go

@@ -408,37 +408,6 @@ func (j JSONType) IsUnsupported() bool {
 	return true
 }
 
-// JSON_VALID(val)
-//
-// Returns 0 or 1 to indicate whether a value is valid JSON. Returns NULL if the argument is NULL.
-//
-// https://dev.mysql.com/doc/refman/8.0/en/json-attribute-functions.html#function_json-valid
-type JSONValid struct {
-	sql.Expression
-}
-
-var _ sql.FunctionExpression = JSONValid{}
-
-// NewJSONValid creates a new JSONValid function.
-func NewJSONValid(args ...sql.Expression) (sql.Expression, error) {
-	return nil, ErrUnsupportedJSONFunction.New(JSONValid{}.FunctionName())
-}
-
-// FunctionName implements sql.FunctionExpression
-func (j JSONValid) FunctionName() string {
-	return "json_valid"
-}
-
-// Description implements sql.FunctionExpression
-func (j JSONValid) Description() string {
-	return "returns whether JSON value is valid."
-}
-
-// IsUnsupported implements sql.UnsupportedFunctionStub
-func (j JSONValid) IsUnsupported() bool {
-	return true
-}
-
 //////////////////////////
 // JSON table functions //
 //////////////////////////

sql/expression/function/json/json_valid.go

@@ -0,0 +1,80 @@
+package json
+
+import (
+	"fmt"
+	"github.com/dolthub/go-mysql-server/sql"
+	"github.com/dolthub/go-mysql-server/sql/types"
+)
+
+// JSON_VALID(val)
+//
+// Returns 0 or 1 to indicate whether a value is valid JSON. Returns NULL if the argument is NULL.
+//
+// https://dev.mysql.com/doc/refman/8.0/en/json-attribute-functions.html#function_json-valid
+type JSONValid struct {
+	JSON  sql.Expression
+}
+
+var _ sql.FunctionExpression = JSONValid{}
+
+// NewJSONValid creates a new JSONValid function.
+func NewJSONValid(args ...sql.Expression) (sql.Expression, error) {
+	if len(args) != 1 {
+		return nil, sql.ErrInvalidArgumentNumber.New("JSON_VALID", "1", len(args))
+	}
+	return &JSONValid{args[0]}, nil
+}
+
+// FunctionName implements sql.FunctionExpression
+func (j JSONValid) FunctionName() string {
+	return "json_valid"
+}
+
+// Description implements sql.FunctionExpression
+func (j JSONValid) Description() string {
+	return "returns whether JSON value is valid."
+}
+
+// IsUnsupported implements sql.UnsupportedFunctionStub
+func (j JSONValid) IsUnsupported() bool {
+	return false
+}
+
+func (j JSONValid) Resolved() bool {
+	return j.JSON.Resolved()
+}
+
+func (j JSONValid) String() string {
+	return fmt.Sprintf("%s(%s)", j.FunctionName(), j.JSON.String())
+}
+
+func (j JSONValid) Type() sql.Type {
+	return types.Boolean
+}
+
+func (j JSONValid) IsNullable() bool {
+	return j.JSON.IsNullable()
+}
+
+func (j JSONValid) Eval(ctx *sql.Context, row sql.Row) (interface{}, error) {
+	doc, err := getJSONDocumentFromRow(ctx, row, j.JSON)
+	if err != nil {
+		return false, nil
+	}
+	if doc == nil {
+		return nil, nil
+	}
+	return true, nil
+}
+
+func (j JSONValid) Children() []sql.Expression {
+	return []sql.Expression{j.JSON}
+}
+
+func (j JSONValid) WithChildren(children ...sql.Expression) (sql.Expression, error) {
+	if len(j.Children()) != len(children) {
+		return nil, fmt.Errorf("json_valid did not receive the correct amount of args")
+	}
+
+	return NewJSONValid(children...)
+}

sql/expression/function/json/json_valid_test.go

@@ -0,0 +1,63 @@
+// Copyright 2023 Dolthub, Inc.
+//
+// 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"
+	"gopkg.in/src-d/go-errors.v1"
+
+	"github.com/dolthub/go-mysql-server/sql"
+)
+
+func TestValid(t *testing.T) {
+	_, err := NewJSONValid()
+	require.True(t, errors.Is(err, sql.ErrInvalidArgumentNumber))
+
+	f1 := buildGetFieldExpressions(t, NewJSONValid, 1)
+
+	testCases := []struct {
+		f        sql.Expression
+		row      sql.Row
+		expected interface{}
+	}{
+		{f1, sql.Row{`null`}, true},
+		{f1, sql.Row{`1`}, true},
+		{f1, sql.Row{`[1]`}, true},
+		{f1, sql.Row{`[1, false]`}, true},
+		{f1, sql.Row{`[1, {"a": 1}]`}, true},
+		{f1, sql.Row{`{"a": 1}`}, true},
+		{f1, sql.Row{`{"a": [1, false]}`}, true},
+		{f1, sql.Row{`{"a": [1, {"a": 1}]}`}, true},
+		{f1, sql.Row{`{"a": 1, "b": [2, 3], "c": {"d": "foo"}}`}, true},
+		{f1, sql.Row{nil}, nil},
+		{f1, sql.Row{1}, false},
+		{f1, sql.Row{true}, false},
+		{f1, sql.Row{`incorrect`}, false},
+		{f1, sql.Row{`{"a": 1"}`}, false},
+		{f1, sql.Row{`{1}`}, false},
+		{f1, sql.Row{`[1, "a": 1]`}, false},
+	}
+
+	for _, tt := range testCases {
+		t.Run(tt.f.String(), func(t *testing.T) {
+			require := require.New(t)
+			// any error case will result in output of 'false' value
+			result, _ := tt.f.Eval(sql.NewEmptyContext(), tt.row)
+			require.Equal(tt.expected, result)
+		})
+	}
+}