chore: import upstream snapshot with attribution

server/ast/drop_sequence.go

@@ -0,0 +1,46 @@
+// 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 ast
+
+import (
+	"github.com/cockroachdb/errors"
+
+	vitess "github.com/dolthub/vitess/go/vt/sqlparser"
+
+	"github.com/dolthub/doltgresql/postgres/parser/sem/tree"
+	pgnodes "github.com/dolthub/doltgresql/server/node"
+)
+
+// nodeDropSequence handles *tree.DropSequence nodes.
+func nodeDropSequence(ctx *Context, node *tree.DropSequence) (vitess.Statement, error) {
+	if node == nil {
+		return nil, nil
+	}
+	if len(node.Names) != 1 {
+		return nil, errors.Errorf("dropping multiple sequences in DROP SEQUENCE is not yet supported")
+	}
+	name, err := nodeTableName(ctx, &node.Names[0])
+	if err != nil {
+		return nil, err
+	}
+	if len(name.DbQualifier.String()) > 0 {
+		return nil, errors.Errorf("DROP SEQUENCE is currently only supported for the current database")
+	}
+	return vitess.InjectedStatement{
+		Statement: pgnodes.NewDropSequence(node.IfExists, name.SchemaQualifier.String(), name.Name.String(),
+			node.DropBehavior == tree.DropCascade),
+		Children: nil,
+	}, nil
+}