Bug #12792: @@system_time_zone is not SELECTable

Bug #15684: @@version_* are not all SELECTable

  Added the appropriate information as read-only system variables, and
  also removed some special-case handling of @@version along the way.

  @@version_bdb was added, but isn't included in the test because it
  depends on the presence of BDB.

mysql-test/r/variables.result

@@ -275,7 +275,7 @@ ERROR HY000: Variable 'autocommit' is a SESSION variable and can't be used with
 select @@global.timestamp;
 ERROR HY000: Variable 'timestamp' is a SESSION variable
 set @@version='';
-ERROR HY000: Unknown system variable 'version'
+ERROR HY000: Variable 'version' is a read only variable
 set @@concurrent_insert=1;
 ERROR HY000: Variable 'concurrent_insert' is a GLOBAL variable and should be set with SET GLOBAL
 set @@global.sql_auto_is_null=1;
@@ -384,6 +384,7 @@ select @@sql_max_join_size,@@max_join_size;
 set sql_quote_show_create=1;
 set sql_safe_updates=1;
 set sql_select_limit=1;
+set sql_select_limit=default;
 set sql_warnings=1;
 set global table_cache=100;
 set storage_engine=myisam;
@@ -584,3 +585,11 @@ set @@global.character_set_filesystem=default;
 select @@global.character_set_filesystem;
 @@global.character_set_filesystem
 binary
+select @@system_time_zone;
+@@system_time_zone
+#
+select @@version, @@version_comment, @@version_compile_machine,
+@@version_compile_os;
+@@version	@@version_comment	@@version_compile_machine	@@version_compile_os
+#	#	#	#
+End of 5.0 tests

mysql-test/t/variables.test

@@ -169,7 +169,7 @@ set collation_connection=NULL;
 set global autocommit=1;
 --error 1238
 select @@global.timestamp;
---error 1193
+--error 1238 
 set @@version='';
 --error 1229
 set @@concurrent_insert=1;
@@ -258,6 +258,8 @@ select @@sql_max_join_size,@@max_join_size;
 set sql_quote_show_create=1;
 set sql_safe_updates=1;
 set sql_select_limit=1;
+# reset it, so later tests don't get confused
+set sql_select_limit=default;
 set sql_warnings=1;
 set global table_cache=100;
 set storage_engine=myisam;
@@ -472,4 +474,19 @@ select @@character_set_filesystem;
 set @@global.character_set_filesystem=default;
 select @@global.character_set_filesystem;
 
-# End of 5.0 tests
+#
+# Bug #12792: @@system_time_zone is not SELECTable.
+#
+# Don't actually output, since it depends on the system
+--replace_column 1 #
+select @@system_time_zone;
+
+#
+# Bug #15684: system variables cannot be SELECTed (e.g. @@version_comment)
+#
+# Don't actually output, since it depends on the system
+--replace_column 1 # 2 # 3 # 4 #
+select @@version, @@version_comment, @@version_compile_machine,
+       @@version_compile_os;
+
+--echo End of 5.0 tests

sql/item_func.cc

@@ -4558,12 +4558,6 @@ Item *get_system_var(THD *thd, enum_var_type var_type, LEX_STRING name,
   sys_var *var;
   LEX_STRING *base_name, *component_name;
 
-  if (component.str == 0 &&
-      !my_strcasecmp(system_charset_info, name.str, "VERSION"))
-    return new Item_string(NULL, server_version,
-			   (uint) strlen(server_version),
-			   system_charset_info, DERIVATION_SYSCONST);
-
   if (component.str)
   {
     base_name= &component;

sql/set_var.cc

@@ -377,6 +377,8 @@ sys_var_thd_table_type  sys_table_type("table_type",
 sys_var_thd_storage_engine sys_storage_engine("storage_engine",
 				       &SV::table_type);
 sys_var_bool_ptr	sys_sync_frm("sync_frm", &opt_sync_frm);
+sys_var_const_str	sys_system_time_zone("system_time_zone",
+                                             system_time_zone);
 sys_var_long_ptr	sys_table_cache_size("table_cache",
 					     &table_cache_size);
 sys_var_long_ptr	sys_table_lock_wait_timeout("table_lock_wait_timeout",
@@ -391,6 +393,16 @@ sys_var_thd_ulong	sys_tmp_table_size("tmp_table_size",
 					   &SV::tmp_table_size);
 sys_var_bool_ptr  sys_timed_mutexes("timed_mutexes",
                                     &timed_mutexes);
+sys_var_const_str	sys_version("version", server_version);
+#ifdef HAVE_BERKELEY_DB
+sys_var_const_str	sys_version_bdb("version_bdb", DB_VERSION_STRING);
+#endif
+sys_var_const_str	sys_version_comment("version_comment",
+                                            MYSQL_COMPILATION_COMMENT);
+sys_var_const_str	sys_version_compile_machine("version_compile_machine",
+                                                    MACHINE_TYPE);
+sys_var_const_str	sys_version_compile_os("version_compile_os",
+                                               SYSTEM_TYPE);
 sys_var_thd_ulong	sys_net_wait_timeout("wait_timeout",
 					     &SV::net_wait_timeout);
 
@@ -546,7 +558,6 @@ sys_var_thd_time_zone            sys_time_zone("time_zone");
 
 /* Read only variables */
 
-sys_var_const_str		sys_os("version_compile_os", SYSTEM_TYPE);
 sys_var_readonly                sys_have_innodb("have_innodb", OPT_GLOBAL,
                                                 SHOW_CHAR, get_have_innodb);
 /* Global read-only variable describing server license */
@@ -698,6 +709,7 @@ sys_var *sys_variables[]=
   &sys_sql_notes,
   &sys_storage_engine,
   &sys_sync_frm,
+  &sys_system_time_zone,
   &sys_table_cache_size,
   &sys_table_lock_wait_timeout,
   &sys_table_type,
@@ -710,7 +722,13 @@ sys_var *sys_variables[]=
   &sys_trans_alloc_block_size,
   &sys_trans_prealloc_size,
   &sys_tx_isolation,
-  &sys_os,
+  &sys_version,
+#ifdef HAVE_BERKELEY_DB
+  &sys_version_bdb,
+#endif
+  &sys_version_comment,
+  &sys_version_compile_machine,
+  &sys_version_compile_os,
 #ifdef HAVE_INNOBASE_DB
   &sys_innodb_fast_shutdown,
   &sys_innodb_max_dirty_pages_pct,
@@ -1015,13 +1033,14 @@ struct show_var_st init_vars[]= {
   {sys_tx_isolation.name,     (char*) &sys_tx_isolation,	    SHOW_SYS},
   {sys_updatable_views_with_limit.name,
                               (char*) &sys_updatable_views_with_limit,SHOW_SYS},
-  {"version",                 server_version,                       SHOW_CHAR},
+  {sys_version.name,          (char*) &sys_version,                 SHOW_SYS},
 #ifdef HAVE_BERKELEY_DB
-  {"version_bdb",             (char*) DB_VERSION_STRING,            SHOW_CHAR},
+  {sys_version_bdb.name,      (char*) &sys_version_bdb,             SHOW_SYS},
 #endif
-  {"version_comment",         (char*) MYSQL_COMPILATION_COMMENT,    SHOW_CHAR},
-  {"version_compile_machine", (char*) MACHINE_TYPE,		    SHOW_CHAR},
-  {sys_os.name,		      (char*) &sys_os,			    SHOW_SYS},
+  {sys_version_comment.name,  (char*) &sys_version_comment,         SHOW_SYS},
+  {sys_version_compile_machine.name, (char*) &sys_version_compile_machine,
+   SHOW_SYS},
+  {sys_version_compile_os.name,	(char*) &sys_version_compile_os,    SHOW_SYS},
   {sys_net_wait_timeout.name, (char*) &sys_net_wait_timeout,	    SHOW_SYS},
   {NullS, NullS, SHOW_LONG}
 };