Fix CheckAttributeType's handling of collations for ranges.

Commit fc7695891 changed CheckAttributeType to recurse into ranges,
but made it pass down the wrong collation (always InvalidOid, since
ranges as such have no collation).  This would result in guaranteed
failure when considering a range type whose subtype is collatable.

Embarrassingly, we lack any regression tests that would expose such
a problem (but fortunately, somebody noticed before we shipped this
bug in any release).

Fix it to pass down the range's subtype collation property instead,
and add some regression test cases to exercise collatable-subtype
ranges a bit more.  Back-patch to all supported branches, as the
previous patch was.

Report and patch by Julien Rouhaud, test cases tweaked by me

Discussion: https://postgr.es/m/CAOBaU_aBWqNweiGUFX0guzBKkcfJ8mnnyyGC_KBQmO12Mj5f_A@mail.gmail.com

src/backend/catalog/heap.c

@@ -566,7 +566,8 @@ CheckAttributeType(const char *attname,
 		/*
 		 * If it's a range, recurse to check its subtype.
 		 */
-		CheckAttributeType(attname, get_range_subtype(atttypid), attcollation,
+		CheckAttributeType(attname, get_range_subtype(atttypid),
+						   get_range_collation(atttypid),
 						   containing_rowtypes,
 						   allow_system_table_mods);
 	}

src/backend/utils/cache/lsyscache.c

@@ -2968,3 +2968,29 @@ get_range_subtype(Oid rangeOid)
 	else
 		return InvalidOid;
 }
+
+/*
+ * get_range_collation
+ *		Returns the collation of a given range type
+ *
+ * Returns InvalidOid if the type is not a range type,
+ * or if its subtype is not collatable.
+ */
+Oid
+get_range_collation(Oid rangeOid)
+{
+	HeapTuple	tp;
+
+	tp = SearchSysCache1(RANGETYPE, ObjectIdGetDatum(rangeOid));
+	if (HeapTupleIsValid(tp))
+	{
+		Form_pg_range rngtup = (Form_pg_range) GETSTRUCT(tp);
+		Oid			result;
+
+		result = rngtup->rngcollation;
+		ReleaseSysCache(tp);
+		return result;
+	}
+	else
+		return InvalidOid;
+}

src/include/utils/lsyscache.h

@@ -154,6 +154,7 @@ extern void free_attstatsslot(Oid atttype,
 				  float4 *numbers, int nnumbers);
 extern char *get_namespace_name(Oid nspid);
 extern Oid	get_range_subtype(Oid rangeOid);
+extern Oid	get_range_collation(Oid rangeOid);
 
 #define type_is_array(typid)  (get_element_type(typid) != InvalidOid)
 /* type_is_array_domain accepts both plain arrays and domains over arrays */

src/test/regress/expected/rangetypes.out

@@ -564,8 +564,95 @@ select * from numrange_test natural join numrange_test2 order by nr;
 set enable_nestloop to default;
 set enable_hashjoin to default;
 set enable_mergejoin to default;
-DROP TABLE numrange_test;
+-- keep numrange_test around to help exercise dump/reload
 DROP TABLE numrange_test2;
+--
+-- Apply a subset of the above tests on a collatable type, too
+--
+CREATE TABLE textrange_test (tr textrange);
+create index textrange_test_btree on textrange_test(tr);
+INSERT INTO textrange_test VALUES('[,)');
+INSERT INTO textrange_test VALUES('["a",]');
+INSERT INTO textrange_test VALUES('[,"q")');
+INSERT INTO textrange_test VALUES(textrange('b', 'g'));
+INSERT INTO textrange_test VALUES('empty');
+INSERT INTO textrange_test VALUES(textrange('d', 'd', '[]'));
+SELECT tr, isempty(tr), lower(tr), upper(tr) FROM textrange_test;
+  tr   | isempty | lower | upper 
+-------+---------+-------+-------
+ (,)   | f       |       | 
+ [a,)  | f       | a     | 
+ (,q)  | f       |       | q
+ [b,g) | f       | b     | g
+ empty | t       |       | 
+ [d,d] | f       | d     | d
+(6 rows)
+
+SELECT tr, lower_inc(tr), lower_inf(tr), upper_inc(tr), upper_inf(tr) FROM textrange_test;
+  tr   | lower_inc | lower_inf | upper_inc | upper_inf 
+-------+-----------+-----------+-----------+-----------
+ (,)   | f         | t         | f         | t
+ [a,)  | t         | f         | f         | t
+ (,q)  | f         | t         | f         | f
+ [b,g) | t         | f         | f         | f
+ empty | f         | f         | f         | f
+ [d,d] | t         | f         | t         | f
+(6 rows)
+
+SELECT * FROM textrange_test WHERE range_contains(tr, textrange('f', 'fx'));
+  tr   
+-------
+ (,)
+ [a,)
+ (,q)
+ [b,g)
+(4 rows)
+
+SELECT * FROM textrange_test WHERE tr @> textrange('a', 'z');
+  tr  
+------
+ (,)
+ [a,)
+(2 rows)
+
+SELECT * FROM textrange_test WHERE range_contained_by(textrange('0','9'), tr);
+  tr  
+------
+ (,)
+ (,q)
+(2 rows)
+
+SELECT * FROM textrange_test WHERE 'e'::text <@ tr;
+  tr   
+-------
+ (,)
+ [a,)
+ (,q)
+ [b,g)
+(4 rows)
+
+select * from textrange_test where tr = 'empty';
+  tr   
+-------
+ empty
+(1 row)
+
+select * from textrange_test where tr = '("b","g")';
+ tr 
+----
+(0 rows)
+
+select * from textrange_test where tr = '["b","g")';
+  tr   
+-------
+ [b,g)
+(1 row)
+
+select * from textrange_test where tr < 'empty';
+ tr 
+----
+(0 rows)
+
 -- test canonical form for int4range
 select int4range(1, 10, '[]');
  int4range 

src/test/regress/expected/sanity_check.out

@@ -81,6 +81,7 @@ num_exp_sqrt|t
 num_exp_sub|t
 num_input_test|f
 num_result|f
+numrange_test|t
 onek|t
 onek2|t
 path_tbl|f
@@ -162,6 +163,7 @@ test_range_spgist|t
 test_tsvector|f
 testjsonb|f
 text_tbl|f
+textrange_test|t
 time_tbl|f
 timestamp_tbl|f
 timestamptz_tbl|f

src/test/regress/sql/rangetypes.sql

@@ -144,9 +144,37 @@ set enable_nestloop to default;
 set enable_hashjoin to default;
 set enable_mergejoin to default;
 
-DROP TABLE numrange_test;
+-- keep numrange_test around to help exercise dump/reload
 DROP TABLE numrange_test2;
 
+--
+-- Apply a subset of the above tests on a collatable type, too
+--
+
+CREATE TABLE textrange_test (tr textrange);
+create index textrange_test_btree on textrange_test(tr);
+
+INSERT INTO textrange_test VALUES('[,)');
+INSERT INTO textrange_test VALUES('["a",]');
+INSERT INTO textrange_test VALUES('[,"q")');
+INSERT INTO textrange_test VALUES(textrange('b', 'g'));
+INSERT INTO textrange_test VALUES('empty');
+INSERT INTO textrange_test VALUES(textrange('d', 'd', '[]'));
+
+SELECT tr, isempty(tr), lower(tr), upper(tr) FROM textrange_test;
+SELECT tr, lower_inc(tr), lower_inf(tr), upper_inc(tr), upper_inf(tr) FROM textrange_test;
+
+SELECT * FROM textrange_test WHERE range_contains(tr, textrange('f', 'fx'));
+SELECT * FROM textrange_test WHERE tr @> textrange('a', 'z');
+SELECT * FROM textrange_test WHERE range_contained_by(textrange('0','9'), tr);
+SELECT * FROM textrange_test WHERE 'e'::text <@ tr;
+
+select * from textrange_test where tr = 'empty';
+select * from textrange_test where tr = '("b","g")';
+select * from textrange_test where tr = '["b","g")';
+select * from textrange_test where tr < 'empty';
+
+
 -- test canonical form for int4range
 select int4range(1, 10, '[]');
 select int4range(1, 10, '[)');