Add some platform-independent tests for the collation feature.

There's a lot we can't test very well without platform dependencies,
but the C/POSIX collations should now work the same way everywhere.

src/test/regress/parallel_schedule

@@ -76,7 +76,11 @@ ignore: random
 # ----------
 test: select_into select_distinct select_distinct_on select_implicit select_having subselect union case join aggregates transactions random portals arrays btree_index hash_index update namespace prepared_xacts delete
 
-test: privileges security_label
+# ----------
+# Another group of parallel tests
+# ----------
+test: privileges security_label collate
+
 test: misc
 # rules cannot run concurrently with any test that creates a view
 test: rules

src/test/regress/serial_schedule

@@ -89,6 +89,7 @@ test: namespace
 test: prepared_xacts
 test: privileges
 test: security_label
+test: collate
 test: misc
 test: rules
 test: select_views

src/test/regress/sql/collate.sql

+/*
+ * This test is intended to pass on all platforms supported by Postgres.
+ * We can therefore only assume that the default, C, and POSIX collations
+ * are available --- and since the regression tests are often run in a
+ * C-locale database, these may well all have the same behavior.  But
+ * fortunately, the system doesn't know that and will treat them as
+ * incompatible collations.  It is therefore at least possible to test
+ * parser behaviors such as collation conflict resolution.  This test will,
+ * however, be more revealing when run in a database with non-C locale,
+ * since any departure from C sorting behavior will show as a failure.
+ */
+
+CREATE SCHEMA collate_tests;
+SET search_path = collate_tests;
+
+CREATE TABLE collate_test1 (
+    a int,
+    b text COLLATE "C" NOT NULL
+);
+
+\d collate_test1
+
+CREATE TABLE collate_test_fail (
+    a int COLLATE "C",
+    b text
+);
+
+CREATE TABLE collate_test_like (
+    LIKE collate_test1
+);
+
+\d collate_test_like
+
+CREATE TABLE collate_test2 (
+    a int,
+    b text COLLATE "POSIX"
+);
+
+INSERT INTO collate_test1 VALUES (1, 'abc'), (2, 'Abc'), (3, 'bbc'), (4, 'ABD');
+INSERT INTO collate_test2 SELECT * FROM collate_test1;
+
+SELECT * FROM collate_test1 WHERE b COLLATE "C" >= 'abc';
+SELECT * FROM collate_test1 WHERE b >= 'abc' COLLATE "C";
+SELECT * FROM collate_test1 WHERE b COLLATE "C" >= 'abc' COLLATE "C";
+SELECT * FROM collate_test1 WHERE b COLLATE "C" >= 'bbc' COLLATE "POSIX"; -- fail
+
+CREATE DOMAIN testdomain_p AS text COLLATE "POSIX";
+CREATE DOMAIN testdomain_i AS int COLLATE "POSIX"; -- fail
+CREATE TABLE collate_test4 (
+    a int,
+    b testdomain_p
+);
+INSERT INTO collate_test4 SELECT * FROM collate_test1;
+SELECT a, b FROM collate_test4 ORDER BY b;
+
+CREATE TABLE collate_test5 (
+    a int,
+    b testdomain_p COLLATE "C"
+);
+INSERT INTO collate_test5 SELECT * FROM collate_test1;
+SELECT a, b FROM collate_test5 ORDER BY b;
+
+
+SELECT a, b FROM collate_test1 ORDER BY b;
+SELECT a, b FROM collate_test2 ORDER BY b;
+
+SELECT a, b FROM collate_test1 ORDER BY b COLLATE "C";
+
+-- star expansion
+SELECT * FROM collate_test1 ORDER BY b;
+SELECT * FROM collate_test2 ORDER BY b;
+
+-- constant expression folding
+SELECT 'bbc' COLLATE "C" > 'Abc' COLLATE "C" AS "true";
+SELECT 'bbc' COLLATE "POSIX" < 'Abc' COLLATE "POSIX" AS "false";
+
+-- upper/lower
+
+CREATE TABLE collate_test10 (
+    a int,
+    x text COLLATE "C",
+    y text COLLATE "POSIX"
+);
+
+INSERT INTO collate_test10 VALUES (1, 'hij', 'hij'), (2, 'HIJ', 'HIJ');
+
+SELECT a, lower(x), lower(y), upper(x), upper(y), initcap(x), initcap(y) FROM collate_test10;
+SELECT a, lower(x COLLATE "C"), lower(y COLLATE "C") FROM collate_test10;
+
+SELECT a, x, y FROM collate_test10 ORDER BY lower(y), a;
+
+-- backwards parsing
+
+CREATE VIEW collview1 AS SELECT * FROM collate_test1 WHERE b COLLATE "C" >= 'bbc';
+CREATE VIEW collview2 AS SELECT a, b FROM collate_test1 ORDER BY b COLLATE "C";
+CREATE VIEW collview3 AS SELECT a, lower((x || x) COLLATE "POSIX") FROM collate_test10;
+
+SELECT table_name, view_definition FROM information_schema.views
+  WHERE table_name LIKE 'collview%' ORDER BY 1;
+
+
+-- collation propagation in various expression type
+
+SELECT a, coalesce(b, 'foo') FROM collate_test1 ORDER BY 2;
+SELECT a, coalesce(b, 'foo') FROM collate_test2 ORDER BY 2;
+SELECT a, lower(coalesce(x, 'foo')), lower(coalesce(y, 'foo')) FROM collate_test10;
+
+SELECT a, b, greatest(b, 'CCC') FROM collate_test1 ORDER BY 3;
+SELECT a, b, greatest(b, 'CCC') FROM collate_test2 ORDER BY 3;
+SELECT a, x, y, lower(greatest(x, 'foo')), lower(greatest(y, 'foo')) FROM collate_test10;
+
+SELECT a, nullif(b, 'abc') FROM collate_test1 ORDER BY 2;
+SELECT a, nullif(b, 'abc') FROM collate_test2 ORDER BY 2;
+SELECT a, lower(nullif(x, 'foo')), lower(nullif(y, 'foo')) FROM collate_test10;
+
+SELECT a, CASE b WHEN 'abc' THEN 'abcd' ELSE b END FROM collate_test1 ORDER BY 2;
+SELECT a, CASE b WHEN 'abc' THEN 'abcd' ELSE b END FROM collate_test2 ORDER BY 2;
+
+CREATE DOMAIN testdomain AS text;
+SELECT a, b::testdomain FROM collate_test1 ORDER BY 2;
+SELECT a, b::testdomain FROM collate_test2 ORDER BY 2;
+SELECT a, b::testdomain_p FROM collate_test2 ORDER BY 2;
+SELECT a, lower(x::testdomain), lower(y::testdomain) FROM collate_test10;
+
+SELECT min(b), max(b) FROM collate_test1;
+SELECT min(b), max(b) FROM collate_test2;
+
+SELECT array_agg(b ORDER BY b) FROM collate_test1;
+SELECT array_agg(b ORDER BY b) FROM collate_test2;
+
+SELECT a, b FROM collate_test1 UNION ALL SELECT a, b FROM collate_test1 ORDER BY 2;
+SELECT a, b FROM collate_test2 UNION SELECT a, b FROM collate_test2 ORDER BY 2;
+SELECT a, b FROM collate_test2 WHERE a < 4 INTERSECT SELECT a, b FROM collate_test2 WHERE a > 1 ORDER BY 2;
+SELECT a, b FROM collate_test2 EXCEPT SELECT a, b FROM collate_test2 WHERE a < 2 ORDER BY 2;
+
+SELECT a, b FROM collate_test1 UNION ALL SELECT a, b FROM collate_test2 ORDER BY 2; -- fail
+SELECT a, b FROM collate_test1 UNION ALL SELECT a, b FROM collate_test2; -- ok
+SELECT a, b FROM collate_test1 UNION SELECT a, b FROM collate_test2 ORDER BY 2; -- fail
+SELECT a, b COLLATE "C" FROM collate_test1 UNION SELECT a, b FROM collate_test2 ORDER BY 2; -- ok
+SELECT a, b FROM collate_test1 INTERSECT SELECT a, b FROM collate_test2 ORDER BY 2; -- fail
+SELECT a, b FROM collate_test1 EXCEPT SELECT a, b FROM collate_test2 ORDER BY 2; -- fail
+
+CREATE TABLE test_u AS SELECT a, b FROM collate_test1 UNION ALL SELECT a, b FROM collate_test2; -- fail
+
+-- ideally this would be a parse-time error, but for now it must be run-time:
+select x < y from collate_test10; -- fail
+select x || y from collate_test10; -- ok, because || is not collation aware
+
+-- collation mismatch between recursive and non-recursive term
+WITH RECURSIVE foo(x) AS
+   (SELECT x FROM (VALUES('a' COLLATE "C"),('b')) t(x)
+   UNION ALL
+   SELECT (x || 'c') COLLATE "POSIX" FROM foo WHERE length(x) < 10)
+SELECT * FROM foo;
+
+
+-- casting
+
+SELECT CAST('42' AS text COLLATE "C");
+
+SELECT a, CAST(b AS varchar) FROM collate_test1 ORDER BY 2;
+SELECT a, CAST(b AS varchar) FROM collate_test2 ORDER BY 2;
+
+
+-- polymorphism
+
+SELECT * FROM unnest((SELECT array_agg(b ORDER BY b) FROM collate_test1)) ORDER BY 1;
+SELECT * FROM unnest((SELECT array_agg(b ORDER BY b) FROM collate_test2)) ORDER BY 1;
+
+CREATE FUNCTION dup (f1 anyelement, f2 out anyelement, f3 out anyarray)
+    AS 'select $1, array[$1,$1]' LANGUAGE sql;
+
+SELECT a, (dup(b)).* FROM collate_test1 ORDER BY 2;
+SELECT a, (dup(b)).* FROM collate_test2 ORDER BY 2;
+
+
+-- indexes
+
+CREATE INDEX collate_test1_idx1 ON collate_test1 (b);
+CREATE INDEX collate_test1_idx2 ON collate_test1 (b COLLATE "C");
+CREATE INDEX collate_test1_idx3 ON collate_test1 ((b COLLATE "C")); -- this is different grammatically
+
+CREATE INDEX collate_test1_idx4 ON collate_test1 (a COLLATE "C"); -- fail
+CREATE INDEX collate_test1_idx5 ON collate_test1 ((a COLLATE "C")); -- fail
+
+SELECT relname, pg_get_indexdef(oid) FROM pg_class WHERE relname LIKE 'collate_test%_idx%';
+
+--
+-- Clean up.  Many of these table names will be re-used if the user is
+-- trying to run any platform-specific collation tests later, so we
+-- must get rid of them.
+--
+DROP SCHEMA collate_tests CASCADE;