Handle multi-command SQL strings correctly even when there are 'null' sql

commands.

Reported by Krzysztof Nienartowicz

3 files changed, 66 insertions, 11 deletions

diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 796292537f..00744a4980 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -788,17 +788,35 @@ stmtmulti:	stmtmulti ';' stmt
 						 * the ';' token, add '\0' at the corresponding offset
 						 * to get a separated command.
 						 */
-						last = list_tail($1->queries);
-						query = palloc(@2 - $1->offset + 1);
-						memcpy(query, lfirst(last), @2 - $1->offset);
-						query[@2 - $1->offset] = '\0';
-
-						lfirst(last) = query;
-						query = scanner_get_query(@3, -1, yyscanner);
-						$1->offset = @2;
-						$1->parsetrees = lappend($1->parsetrees, $3);
-						$1->queries = lappend($1->queries, query);
-						$$ = $1;
+						if ($1 != NULL)
+						{
+							last = list_tail($1->queries);
+							query = palloc(@2 - $1->offset + 1);
+							memcpy(query, lfirst(last), @2 - $1->offset);
+							query[@2 - $1->offset] = '\0';
+							lfirst(last) = query;
+
+							query = scanner_get_query(@3, -1, yyscanner);
+							$1->offset = @2;
+							$1->parsetrees = lappend($1->parsetrees, $3);
+							$1->queries = lappend($1->queries, query);
+							$$ = $1;
+						}
+						/*
+						 *
+						 * If the earlier statements were all null, then we
+						 * must initialise the StmtMulti structure and make
+						 * singleton lists
+						 */
+						else
+						{
+							StmtMulti *n = (StmtMulti *) palloc0(sizeof (StmtMulti));
+							query = scanner_get_query(@3, -1, yyscanner);
+							n->offset = @2;
+							n->parsetrees = list_make1($3);
+							n->queries = list_make1(query);
+							$$ = n;
+						}
 					}
 					else
 						$$ = $1;
diff --git a/src/test/regress/input/misc.source b/src/test/regress/input/misc.source
index c46223bedf..9be4a61618 100644
--- a/src/test/regress/input/misc.source
+++ b/src/test/regress/input/misc.source
@@ -276,3 +276,14 @@ drop table oldstyle_test;
 --
 -- rewrite rules
 --
+
+--
+-- multi-statement cases
+--
+create table testtab_multi (a int, b int); create index testtab_multi_indx on testtab_multi(a); drop table testtab_multi;
+;create table testtab_multi (a int, b int); create index testtab_multi_indx on testtab_multi(a); drop table testtab_multi;
+;;select 1;;create table testtab_multi (a int, b int);;;;; create index testtab_multi_indx on testtab_multi(a);;; drop table testtab_multi;
+create table testtab_multi (a int, b int);;;;; create index testtab_multi_indx on testtab_multi(a);;insert into testtab_multi values (1, 2), (3,4); select * from testtab_multi order by a;drop table testtab_multi;
+;create table testtab_multi (a int, b int);;;;; create index testtab_multi_indx on testtab_multi(a);;insert into testtab_multi values (1, 2), (3,4); select * from testtab_multi_nonexist order by a;drop table testtab_multi;
+;;create table testtab_multi (a int, b int);;;;; create index testtab_multi_indx on testtab_multi(a);;insert into testtab_multi values (1, 2), (3,4); select * from testtab_multi_nonexist order by a;drop table testtab_multi;
+
diff --git a/src/test/regress/output/misc.source b/src/test/regress/output/misc.source
index 696c3645f5..fc092bbf98 100644
--- a/src/test/regress/output/misc.source
+++ b/src/test/regress/output/misc.source
@@ -854,3 +854,29 @@ drop table oldstyle_test;
 --
 -- rewrite rules
 --
+--
+-- multi-statement cases
+--
+create table testtab_multi (a int, b int); create index testtab_multi_indx on testtab_multi(a); drop table testtab_multi;
+;create table testtab_multi (a int, b int); create index testtab_multi_indx on testtab_multi(a); drop table testtab_multi;
+;;select 1;;create table testtab_multi (a int, b int);;;;; create index testtab_multi_indx on testtab_multi(a);;; drop table testtab_multi;
+ ?column? 
+----------
+        1
+(1 row)
+
+create table testtab_multi (a int, b int);;;;; create index testtab_multi_indx on testtab_multi(a);;insert into testtab_multi values (1, 2), (3,4); select * from testtab_multi order by a;drop table testtab_multi;
+ a | b 
+---+---
+ 1 | 2
+ 3 | 4
+(2 rows)
+
+;create table testtab_multi (a int, b int);;;;; create index testtab_multi_indx on testtab_multi(a);;insert into testtab_multi values (1, 2), (3,4); select * from testtab_multi_nonexist order by a;drop table testtab_multi;
+ERROR:  relation "testtab_multi_nonexist" does not exist
+LINE 1: select * from testtab_multi_nonexist order by a;
+                      ^
+;;create table testtab_multi (a int, b int);;;;; create index testtab_multi_indx on testtab_multi(a);;insert into testtab_multi values (1, 2), (3,4); select * from testtab_multi_nonexist order by a;drop table testtab_multi;
+ERROR:  relation "testtab_multi_nonexist" does not exist
+LINE 1: select * from testtab_multi_nonexist order by a;
+                      ^