Revert "pg_collation_actual_version() -> pg_collation_current_version()."

This reverts commit 9cf184cc.  Name
change less well received than anticipated.

Discussion: https://postgr.es/m/afcfb97e-88a1-a540-db95-6c573b93bc2b%40eisentraut.org

doc/src/sgml/func.sgml

@@ -26238,14 +26238,14 @@ postgres=# SELECT * FROM pg_walfile_name_offset(pg_stop_backup());
       <row>
        <entry role="func_table_entry"><para role="func_signature">
         <indexterm>
-         <primary>pg_collation_current_version</primary>
+         <primary>pg_collation_actual_version</primary>
         </indexterm>
-        <function>pg_collation_current_version</function> ( <type>oid</type> )
+        <function>pg_collation_actual_version</function> ( <type>oid</type> )
         <returnvalue>text</returnvalue>
        </para>
        <para>
-        Returns the version of the collation object as reported by the ICU
-        library or operating system.  <literal>null</literal> is returned
+        Returns the actual version of the collation object as it is currently
+        installed in the operating system.  <literal>null</literal> is returned
         on operating systems where <productname>PostgreSQL</productname>
         doesn't have support for versions.
        </para></entry>

src/backend/commands/collationcmds.c

@@ -268,7 +268,7 @@ IsThereCollationInNamespace(const char *collname, Oid nspOid)
 }
 
 Datum
-pg_collation_current_version(PG_FUNCTION_ARGS)
+pg_collation_actual_version(PG_FUNCTION_ARGS)
 {
 	Oid			collid = PG_GETARG_OID(0);
 	char	   *version;

src/backend/utils/adt/pg_locale.c

@@ -127,8 +127,8 @@ static char *IsoLocaleName(const char *);	/* MSVC specific */
 static void icu_set_collation_attributes(UCollator *collator, const char *loc);
 #endif
 
-static char *get_collation_current_version(char collprovider,
-										   const char *collcollate);
+static char *get_collation_actual_version(char collprovider,
+										  const char *collcollate);
 
 /*
  * pg_perm_setlocale
@@ -1610,7 +1610,7 @@ pg_newlocale_from_collation(Oid collid)
  * the operating system/library.
  */
 static char *
-get_collation_current_version(char collprovider, const char *collcollate)
+get_collation_actual_version(char collprovider, const char *collcollate)
 {
 	char	   *collversion = NULL;
 
@@ -1717,8 +1717,8 @@ get_collation_version_for_oid(Oid oid, bool missing_ok)
 		if (!HeapTupleIsValid(tp))
 			elog(ERROR, "cache lookup failed for database %u", MyDatabaseId);
 		dbform = (Form_pg_database) GETSTRUCT(tp);
-		version = get_collation_current_version(COLLPROVIDER_LIBC,
-												NameStr(dbform->datcollate));
+		version = get_collation_actual_version(COLLPROVIDER_LIBC,
+											   NameStr(dbform->datcollate));
 	}
 	else
 	{
@@ -1732,8 +1732,8 @@ get_collation_version_for_oid(Oid oid, bool missing_ok)
 			elog(ERROR, "cache lookup failed for collation %u", oid);
 		}
 		collform = (Form_pg_collation) GETSTRUCT(tp);
-		version = get_collation_current_version(collform->collprovider,
-												NameStr(collform->collcollate));
+		version = get_collation_actual_version(collform->collprovider,
+											   NameStr(collform->collcollate));
 	}
 
 	ReleaseSysCache(tp);

src/include/catalog/catversion.h

@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	202102221
+#define CATALOG_VERSION_NO	202102191
 
 #endif

src/include/catalog/pg_proc.dat

@@ -11321,9 +11321,9 @@
 
 { oid => '3448',
   descr => 'get actual version of collation from operating system',
-  proname => 'pg_collation_current_version', procost => '100',
+  proname => 'pg_collation_actual_version', procost => '100',
   provolatile => 'v', prorettype => 'text', proargtypes => 'oid',
-  prosrc => 'pg_collation_current_version' },
+  prosrc => 'pg_collation_actual_version' },
 
 # system management/monitoring related functions
 { oid => '3353', descr => 'list files in the log directory',

src/test/regress/expected/collate.icu.utf8.out

@@ -2018,7 +2018,7 @@ SELECT objid::regclass::text collate "C", refobjid::regcollation::text collate "
 CASE
 WHEN refobjid = 'default'::regcollation THEN 'XXX' -- depends on libc version support
 WHEN refobjversion IS NULL THEN 'version not tracked'
-WHEN refobjversion = pg_collation_current_version(refobjid) THEN 'up to date'
+WHEN refobjversion = pg_collation_actual_version(refobjid) THEN 'up to date'
 ELSE 'out of date'
 END AS version
 FROM pg_depend d
@@ -2156,14 +2156,14 @@ RESET client_min_messages;
 -- leave a collation for pg_upgrade test
 CREATE COLLATION coll_icu_upgrade FROM "und-x-icu";
 -- Test user-visible function for inspecting versions
-SELECT pg_collation_current_version('"en-x-icu"'::regcollation) is not null;
+SELECT pg_collation_actual_version('"en-x-icu"'::regcollation) is not null;
  ?column? 
 ----------
  t
 (1 row)
 
 -- Invalid OIDs are silently ignored
-SELECT pg_collation_current_version(0) is null;
+SELECT pg_collation_actual_version(0) is null;
  ?column? 
 ----------
  t

src/test/regress/sql/collate.icu.utf8.sql

@@ -820,7 +820,7 @@ SELECT objid::regclass::text collate "C", refobjid::regcollation::text collate "
 CASE
 WHEN refobjid = 'default'::regcollation THEN 'XXX' -- depends on libc version support
 WHEN refobjversion IS NULL THEN 'version not tracked'
-WHEN refobjversion = pg_collation_current_version(refobjid) THEN 'up to date'
+WHEN refobjversion = pg_collation_actual_version(refobjid) THEN 'up to date'
 ELSE 'out of date'
 END AS version
 FROM pg_depend d
@@ -885,6 +885,6 @@ RESET client_min_messages;
 CREATE COLLATION coll_icu_upgrade FROM "und-x-icu";
 
 -- Test user-visible function for inspecting versions
-SELECT pg_collation_current_version('"en-x-icu"'::regcollation) is not null;
+SELECT pg_collation_actual_version('"en-x-icu"'::regcollation) is not null;
 -- Invalid OIDs are silently ignored
-SELECT pg_collation_current_version(0) is null;
+SELECT pg_collation_actual_version(0) is null;