Fix quoting when dispatching SAVEPOINT commands.

Fixes github issue #6345.
Reviewed-by: NDaniel Gustafsson <dgustafsson@pivotal.io>

src/backend/access/transam/xact.c

@@ -61,6 +61,7 @@
 #include "utils/memutils.h"
 #include "utils/relmapper.h"
 
+#include "utils/builtins.h"
 #include "utils/resource_manager.h"
 #include "utils/sharedsnapshot.h"
 #include "access/clog.h"
@@ -4578,7 +4579,7 @@ DefineDispatchSavepoint(char *name)
 	{
 		char	   *cmd;
 
-		cmd = psprintf("SAVEPOINT %s", name);
+		cmd = psprintf("SAVEPOINT %s", quote_identifier(name));
 
 		/*
 		 * dispatch a DTX command, in the event of an error, this call
@@ -4711,7 +4712,7 @@ ReleaseSavepoint(List *options)
 	{
 		char	   *cmd;
 
-		cmd = psprintf("RELEASE SAVEPOINT %s", name);
+		cmd = psprintf("RELEASE SAVEPOINT %s", quote_identifier(name));
 
 		/*
 		 * dispatch a DTX command, in the event of an error, this call will
@@ -4878,7 +4879,7 @@ DispatchRollbackToSavepoint(char *name)
 	if (!name)
 		elog(ERROR, "could not find savepoint name for ROLLBACK TO SAVEPOINT");
 
-	cmd = psprintf("ROLLBACK TO SAVEPOINT %s", name);
+	cmd = psprintf("ROLLBACK TO SAVEPOINT %s", quote_identifier(name));
 
 	/*
 	 * dispatch a DTX command, in the event of an error, this call will

src/test/regress/expected/gpdtm_plpgsql.out

@@ -1013,3 +1013,28 @@ $$ language plpgsql;
 create table stran_tt as select stran_func(b) from stran_foo;
 NOTICE:  Table doesn't have 'DISTRIBUTED BY' clause -- Using column(s) named 'stran_func' as the Greenplum Database data distribution key for this table.
 HINT:  The 'DISTRIBUTED BY' clause determines the distribution of data. Make sure column(s) chosen are the optimal data distribution key to minimize skew.
+--
+-- Check quoting when dispatching savepoints. (Not really PL/pgSQL related,
+-- but here for lack of a better place.)
+--
+BEGIN;
+CREATE TEMPORARY TABLE savepointtest (t text);
+NOTICE:  Table doesn't have 'DISTRIBUTED BY' clause -- Using column named 't' as the Greenplum Database data distribution key for this table.
+HINT:  The 'DISTRIBUTED BY' clause determines the distribution of data. Make sure column(s) chosen are the optimal data distribution key to minimize skew.
+INSERT INTO savepointtest VALUES ('before savepoints');
+SAVEPOINT "evil""savepoint1";
+INSERT INTO savepointtest VALUES ('after sp 1');
+SAVEPOINT "evil""savepoint2";
+INSERT INTO savepointtest VALUES ('after sp 2');
+ROLLBACK TO SAVEPOINT "evil""savepoint2";
+RELEASE SAVEPOINT "evil""savepoint1";
+INSERT INTO savepointtest VALUES ('back to top transaction');
+COMMIT;
+SELECT * FROM savepointtest;
+            t            
+-------------------------
+ before savepoints
+ after sp 1
+ back to top transaction
+(3 rows)
+

src/test/regress/sql/gpdtm_plpgsql.sql

@@ -372,3 +372,21 @@ end;
 $$ language plpgsql;
 
 create table stran_tt as select stran_func(b) from stran_foo;
+
+
+--
+-- Check quoting when dispatching savepoints. (Not really PL/pgSQL related,
+-- but here for lack of a better place.)
+--
+BEGIN;
+CREATE TEMPORARY TABLE savepointtest (t text);
+INSERT INTO savepointtest VALUES ('before savepoints');
+SAVEPOINT "evil""savepoint1";
+INSERT INTO savepointtest VALUES ('after sp 1');
+SAVEPOINT "evil""savepoint2";
+INSERT INTO savepointtest VALUES ('after sp 2');
+ROLLBACK TO SAVEPOINT "evil""savepoint2";
+RELEASE SAVEPOINT "evil""savepoint1";
+INSERT INTO savepointtest VALUES ('back to top transaction');
+COMMIT;
+SELECT * FROM savepointtest;