Add more fields to the marshal output of column (#15622)

Signed-off-by: Manan Gupta <manan@planetscale.com>

Author: GuptaManan100

go/vt/vtgate/vindexes/vschema.go

@@ -203,16 +203,22 @@ type Column struct {
 // MarshalJSON returns a JSON representation of Column.
 func (col *Column) MarshalJSON() ([]byte, error) {
 	cj := struct {
-		Name      string `json:"name"`
-		Type      string `json:"type,omitempty"`
-		Invisible bool   `json:"invisible,omitempty"`
-		Default   string `json:"default,omitempty"`
+		Name      string   `json:"name"`
+		Type      string   `json:"type,omitempty"`
+		Invisible bool     `json:"invisible,omitempty"`
+		Default   string   `json:"default,omitempty"`
+		Size      int32    `json:"size,omitempty"`
+		Scale     int32    `json:"scale,omitempty"`
+		Nullable  bool     `json:"nullable,omitempty"`
+		Values    []string `json:"values,omitempty"`
 	}{
-		Name: col.Name.String(),
-		Type: querypb.Type_name[int32(col.Type)],
-	}
-	if col.Invisible {
-		cj.Invisible = true
+		Name:      col.Name.String(),
+		Type:      querypb.Type_name[int32(col.Type)],
+		Invisible: col.Invisible,
+		Size:      col.Size,
+		Scale:     col.Scale,
+		Nullable:  col.Nullable,
+		Values:    col.Values,
 	}
 	if col.Default != nil {
 		cj.Default = sqlparser.String(col.Default)

go/vt/vtgate/vindexes/vschema_test.go

@@ -424,10 +424,12 @@ func TestVSchemaViews(t *testing.T) {
       "columns": [
         {
           "name": "c1",
+          "nullable": true,
           "type": "NULL_TYPE"
         },
         {
           "name": "c2",
+          "nullable": true,
           "type": "VARCHAR"
         }
       ]
@@ -440,6 +442,51 @@ func TestVSchemaViews(t *testing.T) {
 	require.JSONEq(t, want, got)
 }
 
+func TestColumnMarshal(t *testing.T) {
+	tests := []struct {
+		name   string
+		col    Column
+		wanted string
+	}{
+		{
+			name: "Decimal column",
+			col: Column{
+				Name:  sqlparser.NewIdentifierCI("col1"),
+				Type:  sqltypes.Decimal,
+				Size:  15,
+				Scale: 2,
+			},
+			wanted: `{"name":"col1", "scale":2, "size":15, "type":"DECIMAL"}`,
+		},
+		{
+			name: "Decimal column with no scale",
+			col: Column{
+				Name:  sqlparser.NewIdentifierCI("col1"),
+				Type:  sqltypes.Decimal,
+				Size:  15,
+				Scale: 0,
+			},
+			wanted: `{"name":"col1", "size":15, "type":"DECIMAL"}`,
+		},
+		{
+			name: "enum with values column",
+			col: Column{
+				Name:   sqlparser.NewIdentifierCI("col1"),
+				Type:   sqltypes.Enum,
+				Values: []string{"{A", "B\"", "C"},
+			},
+			wanted: `{"name":"col1","type":"ENUM","values":["{A","B\"","C"]}`,
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			res, err := test.col.MarshalJSON()
+			require.NoError(t, err)
+			require.JSONEq(t, test.wanted, string(res), string(res))
+		})
+	}
+}
+
 func TestVSchemaForeignKeys(t *testing.T) {
 	good := vschemapb.SrvVSchema{
 		Keyspaces: map[string]*vschemapb.Keyspace{
@@ -482,10 +529,12 @@ func TestVSchemaForeignKeys(t *testing.T) {
       "columns": [
         {
           "name": "c1",
+		  "nullable": true,
           "type": "NULL_TYPE"
         },
         {
           "name": "c2",
+		  "nullable": true,
           "type": "VARCHAR"
         }
       ],