Fix CREATE INDEX .. VISIBLE/INVISIBLE syntax (pingcap#518)

ast/ddl.go

@@ -548,6 +548,16 @@ func (n *ColumnOption) Accept(v Visitor) (Node, bool) {
 	return v.Leave(n)
 }
 
+// IndexVisibility is the option for index visibility.
+type IndexVisibility int
+
+// IndexVisibility options.
+const (
+	IndexVisibilityDefault IndexVisibility = iota
+	IndexVisibilityVisible
+	IndexVisibilityInvisible
+)
+
 // IndexOption is the index options.
 //    KEY_BLOCK_SIZE [=] value
 //  | index_type
@@ -560,6 +570,7 @@ type IndexOption struct {
 	KeyBlockSize uint64
 	Tp           model.IndexType
 	Comment      string
+	Visibility   IndexVisibility
 }
 
 // Restore implements Node interface.
@@ -587,6 +598,18 @@ func (n *IndexOption) Restore(ctx *RestoreCtx) error {
 		ctx.WriteKeyWord("COMMENT ")
 		ctx.WriteString(n.Comment)
 	}
+
+	if n.Visibility != IndexVisibilityDefault {
+		if hasPrevOption {
+			ctx.WritePlain(" ")
+		}
+		switch n.Visibility {
+		case IndexVisibilityVisible:
+			ctx.WriteKeyWord("VISIBLE")
+		case IndexVisibilityInvisible:
+			ctx.WriteKeyWord("INVISIBLE")
+		}
+	}
 	return nil
 }
 
@@ -1312,7 +1335,7 @@ func (n *CreateIndexStmt) Restore(ctx *RestoreCtx) error {
 	}
 	ctx.WritePlain(")")
 
-	if n.IndexOption.Tp != model.IndexTypeInvalid || n.IndexOption.KeyBlockSize > 0 || n.IndexOption.Comment != "" {
+	if n.IndexOption.Tp != model.IndexTypeInvalid || n.IndexOption.KeyBlockSize > 0 || n.IndexOption.Comment != "" || n.IndexOption.Visibility != IndexVisibilityDefault {
 		ctx.WritePlain(" ")
 		if err := n.IndexOption.Restore(ctx); err != nil {
 			return errors.Annotate(err, "An error occurred while restore CreateIndexStmt.IndexOption")

misc.go

@@ -336,6 +336,7 @@ var tokenMap = map[string]int{
 	"INTERVAL":                 interval,
 	"INTERNAL":                 internal,
 	"INTO":                     into,
+	"INVISIBLE":                invisible,
 	"INVOKER":                  invoker,
 	"IS":                       is,
 	"ISSUER":                   issuer,
@@ -639,6 +640,7 @@ var tokenMap = map[string]int{
 	"VAR_SAMP":                 varSamp,
 	"VIEW":                     view,
 	"VIRTUAL":                  virtual,
+	"VISIBLE":                  visible,
 	"WARNINGS":                 warnings,
 	"ERRORS":                   identSQLErrors,
 	"WEEK":                     week,