pgwire: Add support for cursors enclosed in quotes

In CockroachDB and Postgres, it is possible to declare
cursors with special identifiers enclosed within double
quotes, for e.g. "1-2-3". Currently, we store the name
as an unescaped string which causes problems during the
pgwire DESCRIBE step for looking up the cursor. We should
be storing using the tree.Name datatype for the cursor name
while storing and looking up cursors. This PR updates the code
to start using tree.Name instead of raw strings for handling
cursor names. This fixes the issue where the pgwire DESCRIBE
step fails while attempting to look up cursors with names
containing special characters.

Resolves cockroachdb#84261

Release note (bug fix): The pgwire DESCRIBE step no longer
fails with an error while attempting to look up cursors
declared with names containing special characters.

pkg/sql/conn_executor_prepare.go

@@ -329,7 +329,7 @@ func (ex *connExecutor) execBind(
 			return retErr(pgerror.Newf(
 				pgcode.DuplicateCursor, "portal %q already exists", portalName))
 		}
-		if cursor := ex.getCursorAccessor().getCursor(portalName); cursor != nil {
+		if cursor := ex.getCursorAccessor().getCursor(tree.Name(portalName)); cursor != nil {
 			return retErr(pgerror.Newf(
 				pgcode.DuplicateCursor, "portal %q already exists as cursor", portalName))
 		}
@@ -485,7 +485,7 @@ func (ex *connExecutor) addPortal(
 	if _, ok := ex.extraTxnState.prepStmtsNamespace.portals[portalName]; ok {
 		panic(errors.AssertionFailedf("portal already exists: %q", portalName))
 	}
-	if cursor := ex.getCursorAccessor().getCursor(portalName); cursor != nil {
+	if cursor := ex.getCursorAccessor().getCursor(tree.Name(portalName)); cursor != nil {
 		panic(errors.AssertionFailedf("portal already exists as cursor: %q", portalName))
 	}
 
@@ -564,7 +564,7 @@ func (ex *connExecutor) execDescribe(
 
 	switch descCmd.Type {
 	case pgwirebase.PrepareStatement:
-		ps, ok := ex.extraTxnState.prepStmtsNamespace.prepStmts[descCmd.Name]
+		ps, ok := ex.extraTxnState.prepStmtsNamespace.prepStmts[string(descCmd.Name)]
 		if !ok {
 			return retErr(pgerror.Newf(
 				pgcode.InvalidSQLStatementName,
@@ -594,7 +594,9 @@ func (ex *connExecutor) execDescribe(
 			res.SetPrepStmtOutput(ctx, ps.Columns)
 		}
 	case pgwirebase.PreparePortal:
-		portal, ok := ex.extraTxnState.prepStmtsNamespace.portals[descCmd.Name]
+		// TODO(rimadeodhar): prepStmtsNamespace should also be updated to use tree.Name instead of string
+		// for indexing internal maps.
+		portal, ok := ex.extraTxnState.prepStmtsNamespace.portals[string(descCmd.Name)]
 		if !ok {
 			// Check SQL-level cursors.
 			cursor := ex.getCursorAccessor().getCursor(descCmd.Name)

pkg/sql/conn_io.go

@@ -218,7 +218,7 @@ var _ Command = PrepareStmt{}
 // DescribeStmt is the Command for producing info about a prepared statement or
 // portal.
 type DescribeStmt struct {
-	Name string
+	Name tree.Name
 	Type pgwirebase.PrepareType
 }
 

pkg/sql/logictest/testdata/logic_test/cursor

@@ -557,3 +557,45 @@ CLOSE foo
 
 statement ok
 ALTER TABLE a ADD COLUMN c INT
+
+statement ok
+COMMIT;
+
+statement ok
+BEGIN;
+
+statement ok
+DECLARE "a"" b'c" CURSOR FOR SELECT 1;
+
+query I
+FETCH 1 "a"" b'c";
+----
+1
+
+statement ok
+CLOSE "a"" b'c";
+DECLARE "a b" CURSOR FOR SELECT 2;
+
+query I
+FETCH 1 "a b";
+----
+2
+
+statement ok
+CLOSE "a b";
+DECLARE "a\b" CURSOR FOR SELECT 3;
+
+query I
+FETCH 1 "a\b";
+----
+3
+
+statement ok
+CLOSE "a\b";
+
+query error pq: at or near "b": syntax error
+FETCH 1 a b;
+
+statement ok
+COMMIT;
+

pkg/sql/logictest/testdata/logic_test/pg_catalog

@@ -5742,3 +5742,31 @@ JOIN pg_authid ON usesysid = oid
 ----
 passed
 true
+
+statement ok
+CREATE TABLE t (a INT PRIMARY KEY, b INT);
+INSERT INTO t VALUES (1, 2), (2, 3);
+
+statement ok
+BEGIN;
+
+statement ok
+DECLARE "a"" b'c" CURSOR FOR TABLE t;
+DECLARE "a b" CURSOR FOR TABLE t;
+DECLARE "a\b" CURSOR FOR TABLE t;
+
+## pg_catalog.pg_cursors
+
+query TTBBB colnames
+SELECT name, statement, is_holdable, is_binary, is_scrollable FROM pg_catalog.pg_cursors ORDER BY name;
+----
+name    statement  is_holdable  is_binary  is_scrollable
+a b     TABLE t    false        false      false
+a" b'c  TABLE t    false        false      false
+a\b     TABLE t    false        false      false
+
+statement ok
+COMMIT;
+
+statement ok
+DROP TABLE t;

pkg/sql/pg_catalog.go

@@ -3609,12 +3609,12 @@ https://www.postgresql.org/docs/14/view-pg-cursors.html`,
 				return err
 			}
 			if err := addRow(
-				tree.NewDString(name),        /* name */
-				tree.NewDString(c.statement), /* statement */
-				tree.DBoolFalse,              /* is_holdable */
-				tree.DBoolFalse,              /* is_binary */
-				tree.DBoolFalse,              /* is_scrollable */
-				tz,                           /* creation_date */
+				tree.NewDString(string(name)), /* name */
+				tree.NewDString(c.statement),  /* statement */
+				tree.DBoolFalse,               /* is_holdable */
+				tree.DBoolFalse,               /* is_binary */
+				tree.DBoolFalse,               /* is_scrollable */
+				tz,                            /* creation_date */
 			); err != nil {
 				return err
 			}

pkg/sql/pgwire/conn.go

@@ -1006,7 +1006,7 @@ func (c *conn) handleDescribe(ctx context.Context, buf *pgwirebase.ReadBuffer) e
 	return c.stmtBuf.Push(
 		ctx,
 		sql.DescribeStmt{
-			Name: name,
+			Name: tree.Name(name),
 			Type: typ,
 		})
 }

pkg/sql/pgwire/conn_test.go

@@ -160,6 +160,9 @@ func TestConn(t *testing.T) {
 	if err := finishQuery(generateError, conn); err != nil {
 		t.Fatal(err)
 	}
+	expectExecStmt(ctx, t, "DECLARE \"a b\" CURSOR FOR SELECT 10", &rd, conn, queryStringComplete)
+	expectExecStmt(ctx, t, "FETCH 1 \"a b\"", &rd, conn, queryStringComplete)
+	expectExecStmt(ctx, t, "CLOSE \"a b\"", &rd, conn, queryStringComplete)
 	// We got to the COMMIT at the end of the batch.
 	expectExecStmt(ctx, t, "COMMIT TRANSACTION", &rd, conn, queryStringComplete)
 	expectSync(ctx, t, &rd)
@@ -506,6 +509,9 @@ func client(ctx context.Context, serverAddr net.Addr, wg *sync.WaitGroup) error
 	batch.Queue("BEGIN")
 	batch.Queue("select 7")
 	batch.Queue("select 8")
+	batch.Queue("declare \"a b\" cursor for select 10")
+	batch.Queue("fetch 1 \"a b\"")
+	batch.Queue("close \"a b\"")
 	batch.Queue("COMMIT")
 
 	batchResults := conn.SendBatch(ctx, batch)
@@ -676,7 +682,7 @@ func expectPrepareStmt(
 func expectDescribeStmt(
 	ctx context.Context,
 	t *testing.T,
-	expName string,
+	expName tree.Name,
 	expType pgwirebase.PrepareType,
 	rd *sql.StmtBufReader,
 	c *conn,

pkg/sql/pgwire/testdata/pgtest/portals

@@ -1486,3 +1486,71 @@ ReadyForQuery
 {"Type":"ParseComplete"}
 {"Type":"ErrorResponse","Code":"08P01","Message":"invalid DESCRIBE message subtype 0"}
 {"Type":"ReadyForQuery","TxStatus":"I"}
+
+# Check declaring cursor with a name enclosed in double quotes
+send
+Query {"String": "BEGIN"}
+----
+
+until
+ReadyForQuery
+----
+{"Type":"CommandComplete","CommandTag":"BEGIN"}
+{"Type":"ReadyForQuery","TxStatus":"T"}
+
+send
+Parse {"Query": "DECLARE \"a b\" CURSOR FOR SELECT generate_series(1, 10) AS bar"}
+Bind
+Describe {"ObjectType": "P", "Name": ""}
+Execute
+Sync
+----
+
+until
+ReadyForQuery
+----
+{"Type":"ParseComplete"}
+{"Type":"BindComplete"}
+{"Type":"NoData"}
+{"Type":"CommandComplete","CommandTag":"DECLARE CURSOR"}
+{"Type":"ReadyForQuery","TxStatus":"T"}
+
+send
+Describe {"ObjectType": "P", "Name": "a b"}
+Sync
+----
+
+until ignore_type_oids ignore_table_oids ignore_data_type_sizes
+ReadyForQuery
+----
+{"Type":"RowDescription","Fields":[{"Name":"bar","TableOID":0,"TableAttributeNumber":0,"DataTypeOID":0,"DataTypeSize":0,"TypeModifier":-1,"Format":0}]}
+{"Type":"ReadyForQuery","TxStatus":"T"}
+
+send
+Parse {"Query": "FETCH 2 \"a b\""}
+Bind
+Describe {"ObjectType": "P", "Name": ""}
+Execute
+Sync
+----
+
+until ignore_type_oids ignore_table_oids ignore_data_type_sizes
+ReadyForQuery
+----
+{"Type":"ParseComplete"}
+{"Type":"BindComplete"}
+{"Type":"RowDescription","Fields":[{"Name":"bar","TableOID":0,"TableAttributeNumber":0,"DataTypeOID":0,"DataTypeSize":0,"TypeModifier":-1,"Format":0}]}
+{"Type":"DataRow","Values":[{"text":"1"}]}
+{"Type":"DataRow","Values":[{"text":"2"}]}
+{"Type":"CommandComplete","CommandTag":"FETCH 2"}
+{"Type":"ReadyForQuery","TxStatus":"T"}
+
+send
+Query {"String": "ROLLBACK"}
+----
+
+until
+ReadyForQuery
+----
+{"Type":"CommandComplete","CommandTag":"ROLLBACK"}
+{"Type":"ReadyForQuery","TxStatus":"I"}

pkg/sql/sql_cursor.go

@@ -48,13 +48,12 @@ func (p *planner) DeclareCursor(ctx context.Context, s *tree.DeclareCursor) (pla
 			}
 
 			ie := p.ExecCfg().InternalExecutorFactory(ctx, p.SessionData())
-			cursorName := s.Name.String()
-			if cursor := p.sqlCursors.getCursor(cursorName); cursor != nil {
-				return nil, pgerror.Newf(pgcode.DuplicateCursor, "cursor %q already exists", cursorName)
+			if cursor := p.sqlCursors.getCursor(s.Name); cursor != nil {
+				return nil, pgerror.Newf(pgcode.DuplicateCursor, "cursor %q already exists", s.Name)
 			}
 
-			if p.extendedEvalCtx.PreparedStatementState.HasPortal(cursorName) {
-				return nil, pgerror.Newf(pgcode.DuplicateCursor, "cursor %q already exists as portal", cursorName)
+			if p.extendedEvalCtx.PreparedStatementState.HasPortal(string(s.Name)) {
+				return nil, pgerror.Newf(pgcode.DuplicateCursor, "cursor %q already exists as portal", s.Name)
 			}
 
 			// Try to plan the cursor query to make sure that it's valid.
@@ -99,7 +98,7 @@ func (p *planner) DeclareCursor(ctx context.Context, s *tree.DeclareCursor) (pla
 				statement:    statement,
 				created:      timeutil.Now(),
 			}
-			if err := p.sqlCursors.addCursor(cursorName, cursor); err != nil {
+			if err := p.sqlCursors.addCursor(s.Name, cursor); err != nil {
 				// This case shouldn't happen because cursor names are scoped to a session,
 				// and sessions can't have more than one statement running at once. But
 				// let's be diligent and clean up if it somehow does happen anyway.
@@ -118,11 +117,10 @@ var errBackwardScan = pgerror.Newf(pgcode.ObjectNotInPrerequisiteState, "cursor
 func (p *planner) FetchCursor(
 	_ context.Context, s *tree.CursorStmt, isMove bool,
 ) (planNode, error) {
-	cursorName := s.Name.String()
-	cursor := p.sqlCursors.getCursor(cursorName)
+	cursor := p.sqlCursors.getCursor(s.Name)
 	if cursor == nil {
 		return nil, pgerror.Newf(
-			pgcode.InvalidCursorName, "cursor %q does not exist", cursorName,
+			pgcode.InvalidCursorName, "cursor %q does not exist", s.Name,
 		)
 	}
 	if s.Count < 0 || s.FetchType == tree.FetchBackwardAll {
@@ -242,7 +240,7 @@ func (p *planner) CloseCursor(ctx context.Context, n *tree.CloseCursor) (planNod
 	return &delayedNode{
 		name: n.String(),
 		constructor: func(ctx context.Context, p *planner) (planNode, error) {
-			return newZeroNode(nil /* columns */), p.sqlCursors.closeCursor(n.Name.String())
+			return newZeroNode(nil /* columns */), p.sqlCursors.closeCursor(n.Name)
 		},
 	}, nil
 }
@@ -275,20 +273,20 @@ type sqlCursors interface {
 	closeAll()
 	// closeCursor closes the named cursor, returning an error if that cursor
 	// didn't exist in the set.
-	closeCursor(string) error
+	closeCursor(tree.Name) error
 	// getCursor returns the named cursor, returning nil if that cursor
 	// didn't exist in the set.
-	getCursor(string) *sqlCursor
+	getCursor(tree.Name) *sqlCursor
 	// addCursor adds a new cursor with the given name to the set, returning an
 	// error if the cursor already existed in the set.
-	addCursor(string, *sqlCursor) error
+	addCursor(tree.Name, *sqlCursor) error
 	// list returns all open cursors in the set.
-	list() map[string]*sqlCursor
+	list() map[tree.Name]*sqlCursor
 }
 
 // cursorMap is a sqlCursors that's backed by an actual map.
 type cursorMap struct {
-	cursors map[string]*sqlCursor
+	cursors map[tree.Name]*sqlCursor
 }
 
 func (c *cursorMap) closeAll() {
@@ -298,7 +296,7 @@ func (c *cursorMap) closeAll() {
 	c.cursors = nil
 }
 
-func (c *cursorMap) closeCursor(s string) error {
+func (c *cursorMap) closeCursor(s tree.Name) error {
 	cursor, ok := c.cursors[s]
 	if !ok {
 		return pgerror.Newf(pgcode.InvalidCursorName, "cursor %q does not exist", s)
@@ -308,13 +306,13 @@ func (c *cursorMap) closeCursor(s string) error {
 	return err
 }
 
-func (c *cursorMap) getCursor(s string) *sqlCursor {
+func (c *cursorMap) getCursor(s tree.Name) *sqlCursor {
 	return c.cursors[s]
 }
 
-func (c *cursorMap) addCursor(s string, cursor *sqlCursor) error {
+func (c *cursorMap) addCursor(s tree.Name, cursor *sqlCursor) error {
 	if c.cursors == nil {
-		c.cursors = make(map[string]*sqlCursor)
+		c.cursors = make(map[tree.Name]*sqlCursor)
 	}
 	if _, ok := c.cursors[s]; ok {
 		return pgerror.Newf(pgcode.DuplicateCursor, "cursor %q already exists", s)
@@ -323,7 +321,7 @@ func (c *cursorMap) addCursor(s string, cursor *sqlCursor) error {
 	return nil
 }
 
-func (c *cursorMap) list() map[string]*sqlCursor {
+func (c *cursorMap) list() map[tree.Name]*sqlCursor {
 	return c.cursors
 }
 
@@ -337,19 +335,19 @@ func (c connExCursorAccessor) closeAll() {
 	c.ex.extraTxnState.sqlCursors.closeAll()
 }
 
-func (c connExCursorAccessor) closeCursor(s string) error {
+func (c connExCursorAccessor) closeCursor(s tree.Name) error {
 	return c.ex.extraTxnState.sqlCursors.closeCursor(s)
 }
 
-func (c connExCursorAccessor) getCursor(s string) *sqlCursor {
+func (c connExCursorAccessor) getCursor(s tree.Name) *sqlCursor {
 	return c.ex.extraTxnState.sqlCursors.getCursor(s)
 }
 
-func (c connExCursorAccessor) addCursor(s string, cursor *sqlCursor) error {
+func (c connExCursorAccessor) addCursor(s tree.Name, cursor *sqlCursor) error {
 	return c.ex.extraTxnState.sqlCursors.addCursor(s, cursor)
 }
 
-func (c connExCursorAccessor) list() map[string]*sqlCursor {
+func (c connExCursorAccessor) list() map[tree.Name]*sqlCursor {
 	return c.ex.extraTxnState.sqlCursors.list()
 }