Fix crash when using partition bound expressions

Since 7c079d74, partition bounds are able to use generalized expression
syntax when processed, treating "minvalue" and "maxvalue" as specific
cases as they get passed down for transformation as a column references.

The checks for infinite bounds in range expressions have been lax
though, causing crashes when trying to use column reference names with
more than one field.  Here is an example causing a crash:
CREATE TABLE list_parted (a int) PARTITION BY LIST (a);
CREATE TABLE part_list_crash PARTITION OF list_parted
  FOR VALUES IN (somename.somename);

Note that the creation of the second relation should fail as partition
bounds cannot have column references in their expressions, so when
finding an expression which does not match the expected infinite bounds,
then this commit lets the generic transformation machinery check after
it.  The error message generated in this case references as well a
missing RTE, which is confusing.  This problem will be treated
separately as it impacts as well default expressions for some time, and
for now only the cases where a crash can happen are fixed.

While on it, extend the set of regression tests in place for list
partition bounds and add an extra set for range partition bounds.

Reported-by: Alexander Lakhin
Author: Michael Paquier
Reviewed-by: Amit Langote
Discussion: https://postgr.es/m/15668-0377b1981aa1a393@postgresql.org

src/backend/parser/parse_utilcmd.c

@@ -3746,12 +3746,24 @@ transformPartitionRangeBounds(ParseState *pstate, List *blist,
 			ColumnRef *cref = (ColumnRef *) expr;
 			char *cname = NULL;
 
+			/*
+			 * There should be a single field named either "minvalue" or
+			 * "maxvalue".
+			 */
 			if (list_length(cref->fields) == 1 &&
 				IsA(linitial(cref->fields), String))
 				cname = strVal(linitial(cref->fields));
 
-			Assert(cname != NULL);
-			if (strcmp("minvalue", cname) == 0)
+			if (cname == NULL)
+			{
+				/*
+				 * ColumnRef is not in the desired single-field-name form.
+				 * For consistency between all partition strategies, let the
+				 * expression transformation report any errors rather than
+				 * doing it ourselves.
+				 */
+			}
+			else if (strcmp("minvalue", cname) == 0)
 			{
 				prd = makeNode(PartitionRangeDatum);
 				prd->kind = PARTITION_RANGE_DATUM_MINVALUE;

src/test/regress/expected/create_table.out

@@ -489,11 +489,15 @@ Partitions: part_null FOR VALUES IN (NULL),
             part_p2 FOR VALUES IN (2),
             part_p3 FOR VALUES IN (3)
 
--- forbidden expressions for partition bound
+-- forbidden expressions for partition bound with list partitioned table
 CREATE TABLE part_bogus_expr_fail PARTITION OF list_parted FOR VALUES IN (somename);
 ERROR:  column "somename" does not exist
 LINE 1: ...expr_fail PARTITION OF list_parted FOR VALUES IN (somename);
                                                              ^
+CREATE TABLE part_bogus_expr_fail PARTITION OF list_parted FOR VALUES IN (somename.somename);
+ERROR:  missing FROM-clause entry for table "somename"
+LINE 1: ...expr_fail PARTITION OF list_parted FOR VALUES IN (somename.s...
+                                                             ^
 CREATE TABLE part_bogus_expr_fail PARTITION OF list_parted FOR VALUES IN (a);
 ERROR:  cannot use column references in partition bound expression
 LINE 1: ..._bogus_expr_fail PARTITION OF list_parted FOR VALUES IN (a);
@@ -502,6 +506,14 @@ CREATE TABLE part_bogus_expr_fail PARTITION OF list_parted FOR VALUES IN (sum(a)
 ERROR:  aggregate functions are not allowed in partition bound
 LINE 1: ...s_expr_fail PARTITION OF list_parted FOR VALUES IN (sum(a));
                                                                ^
+CREATE TABLE part_bogus_expr_fail PARTITION OF list_parted FOR VALUES IN (sum(somename));
+ERROR:  column "somename" does not exist
+LINE 1: ..._fail PARTITION OF list_parted FOR VALUES IN (sum(somename))...
+                                                             ^
+CREATE TABLE part_bogus_expr_fail PARTITION OF list_parted FOR VALUES IN (sum(1));
+ERROR:  aggregate functions are not allowed in partition bound
+LINE 1: ...s_expr_fail PARTITION OF list_parted FOR VALUES IN (sum(1));
+                                                               ^
 CREATE TABLE part_bogus_expr_fail PARTITION OF list_parted FOR VALUES IN ((select 1));
 ERROR:  cannot use subquery in partition bound
 LINE 1: ...expr_fail PARTITION OF list_parted FOR VALUES IN ((select 1)...
@@ -558,6 +570,47 @@ DROP TABLE bigintp;
 CREATE TABLE range_parted (
 	a date
 ) PARTITION BY RANGE (a);
+-- forbidden expressions for partition bounds with range partitioned table
+CREATE TABLE part_bogus_expr_fail PARTITION OF range_parted
+  FOR VALUES FROM (somename) TO ('2019-01-01');
+ERROR:  column "somename" does not exist
+LINE 2:   FOR VALUES FROM (somename) TO ('2019-01-01');
+                           ^
+CREATE TABLE part_bogus_expr_fail PARTITION OF range_parted
+  FOR VALUES FROM (somename.somename) TO ('2019-01-01');
+ERROR:  missing FROM-clause entry for table "somename"
+LINE 2:   FOR VALUES FROM (somename.somename) TO ('2019-01-01');
+                           ^
+CREATE TABLE part_bogus_expr_fail PARTITION OF range_parted
+  FOR VALUES FROM (a) TO ('2019-01-01');
+ERROR:  cannot use column references in partition bound expression
+LINE 2:   FOR VALUES FROM (a) TO ('2019-01-01');
+                           ^
+CREATE TABLE part_bogus_expr_fail PARTITION OF range_parted
+  FOR VALUES FROM (max(a)) TO ('2019-01-01');
+ERROR:  aggregate functions are not allowed in partition bound
+LINE 2:   FOR VALUES FROM (max(a)) TO ('2019-01-01');
+                           ^
+CREATE TABLE part_bogus_expr_fail PARTITION OF range_parted
+  FOR VALUES FROM (max(somename)) TO ('2019-01-01');
+ERROR:  column "somename" does not exist
+LINE 2:   FOR VALUES FROM (max(somename)) TO ('2019-01-01');
+                               ^
+CREATE TABLE part_bogus_expr_fail PARTITION OF range_parted
+  FOR VALUES FROM (max('2019-02-01'::date)) TO ('2019-01-01');
+ERROR:  aggregate functions are not allowed in partition bound
+LINE 2:   FOR VALUES FROM (max('2019-02-01'::date)) TO ('2019-01-01'...
+                           ^
+CREATE TABLE part_bogus_expr_fail PARTITION OF range_parted
+  FOR VALUES FROM ((select 1)) TO ('2019-01-01');
+ERROR:  cannot use subquery in partition bound
+LINE 2:   FOR VALUES FROM ((select 1)) TO ('2019-01-01');
+                           ^
+CREATE TABLE part_bogus_expr_fail PARTITION OF range_parted
+  FOR VALUES FROM (generate_series(1, 3)) TO ('2019-01-01');
+ERROR:  set-returning functions are not allowed in partition bound
+LINE 2:   FOR VALUES FROM (generate_series(1, 3)) TO ('2019-01-01');
+                           ^
 -- trying to specify list for range partitioned table
 CREATE TABLE fail_part PARTITION OF range_parted FOR VALUES IN ('a');
 ERROR:  invalid bound specification for a range partition

src/test/regress/sql/create_table.sql

@@ -450,10 +450,13 @@ CREATE TABLE part_p3 PARTITION OF list_parted FOR VALUES IN ((2+1));
 CREATE TABLE part_null PARTITION OF list_parted FOR VALUES IN (null);
 \d+ list_parted
 
--- forbidden expressions for partition bound
+-- forbidden expressions for partition bound with list partitioned table
 CREATE TABLE part_bogus_expr_fail PARTITION OF list_parted FOR VALUES IN (somename);
+CREATE TABLE part_bogus_expr_fail PARTITION OF list_parted FOR VALUES IN (somename.somename);
 CREATE TABLE part_bogus_expr_fail PARTITION OF list_parted FOR VALUES IN (a);
 CREATE TABLE part_bogus_expr_fail PARTITION OF list_parted FOR VALUES IN (sum(a));
+CREATE TABLE part_bogus_expr_fail PARTITION OF list_parted FOR VALUES IN (sum(somename));
+CREATE TABLE part_bogus_expr_fail PARTITION OF list_parted FOR VALUES IN (sum(1));
 CREATE TABLE part_bogus_expr_fail PARTITION OF list_parted FOR VALUES IN ((select 1));
 CREATE TABLE part_bogus_expr_fail PARTITION OF list_parted FOR VALUES IN (generate_series(4, 6));
 
@@ -497,6 +500,24 @@ CREATE TABLE range_parted (
 	a date
 ) PARTITION BY RANGE (a);
 
+-- forbidden expressions for partition bounds with range partitioned table
+CREATE TABLE part_bogus_expr_fail PARTITION OF range_parted
+  FOR VALUES FROM (somename) TO ('2019-01-01');
+CREATE TABLE part_bogus_expr_fail PARTITION OF range_parted
+  FOR VALUES FROM (somename.somename) TO ('2019-01-01');
+CREATE TABLE part_bogus_expr_fail PARTITION OF range_parted
+  FOR VALUES FROM (a) TO ('2019-01-01');
+CREATE TABLE part_bogus_expr_fail PARTITION OF range_parted
+  FOR VALUES FROM (max(a)) TO ('2019-01-01');
+CREATE TABLE part_bogus_expr_fail PARTITION OF range_parted
+  FOR VALUES FROM (max(somename)) TO ('2019-01-01');
+CREATE TABLE part_bogus_expr_fail PARTITION OF range_parted
+  FOR VALUES FROM (max('2019-02-01'::date)) TO ('2019-01-01');
+CREATE TABLE part_bogus_expr_fail PARTITION OF range_parted
+  FOR VALUES FROM ((select 1)) TO ('2019-01-01');
+CREATE TABLE part_bogus_expr_fail PARTITION OF range_parted
+  FOR VALUES FROM (generate_series(1, 3)) TO ('2019-01-01');
+
 -- trying to specify list for range partitioned table
 CREATE TABLE fail_part PARTITION OF range_parted FOR VALUES IN ('a');
 -- trying to specify modulus and remainder for range partitioned table