MDEV-30318: galera error messages in mariadb log without galera enabled

Post-fix to MDEV-30318 and MDEV-22570-related changes:
unified handling of wsrep_provider by code so that "none"
is interpreted as case-insensitive everywhere and that
work with an empty string is supported everywhere.

mysql-test/include/galera_variables_ok.inc

 --disable_query_log
 
---let $galera_variables_ok = `SELECT COUNT(*) = 50 FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES WHERE VARIABLE_NAME LIKE 'wsrep%'`
+--let $galera_variables_ok = `SELECT COUNT(*) = 51 FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES WHERE VARIABLE_NAME LIKE 'wsrep%'`
 
 --if (!$galera_variables_ok) {
 	--skip Galera number of variables has changed!

mysql-test/suite/wsrep/r/wsrep_provider_plugin_defaults.result

 # Correct Galera library found
-SELECT COUNT(*) FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES WHERE VARIABLE_NAME LIKE 'wsrep_provider%';
+SELECT COUNT(*) FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES WHERE VARIABLE_NAME LIKE 'wsrep_provider%' AND VARIABLE_NAME NOT IN (
+'wsrep_provider',
+'wsrep_provider_options',
+'wsrep_provider_base_dir',
+'wsrep_provider_base_port',
+'wsrep_provider_gcache_dir',
+'wsrep_provider_dbug',
+'wsrep_provider_gcache_debug',
+'wsrep_provider_signal',
+'wsrep_provider_gmcast_listen_addr');
 COUNT(*)
-89
+83
 SELECT * FROM INFORMATION_SCHEMA.SYSTEM_VARIABLES
 WHERE VARIABLE_NAME LIKE 'wsrep_provider_%' AND VARIABLE_NAME NOT IN (
 'wsrep_provider',
@@ -9,6 +18,9 @@ WHERE VARIABLE_NAME LIKE 'wsrep_provider_%' AND VARIABLE_NAME NOT IN (
 'wsrep_provider_base_dir',
 'wsrep_provider_base_port',
 'wsrep_provider_gcache_dir',
+'wsrep_provider_dbug',
+'wsrep_provider_gcache_debug',
+'wsrep_provider_signal',
 'wsrep_provider_gmcast_listen_addr')
 ORDER BY VARIABLE_NAME;
 VARIABLE_NAME	WSREP_PROVIDER_BASE_HOST

mysql-test/suite/wsrep/t/variables_debug.test

@@ -8,7 +8,7 @@
 --let $galera_version=26.4.11
 source include/check_galera_version.inc;
 
-source include/galera_variables_ok.inc;
+source include/galera_variables_ok_debug.inc;
 
 --replace_column 2 #
 SHOW GLOBAL STATUS LIKE 'wsrep%';

mysql-test/suite/wsrep/t/wsrep_provider_plugin_defaults.test

@@ -4,7 +4,16 @@
 --let $galera_version=26.4.14
 source include/check_galera_version.inc;
 
-SELECT COUNT(*) FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES WHERE VARIABLE_NAME LIKE 'wsrep_provider%';
+SELECT COUNT(*) FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES WHERE VARIABLE_NAME LIKE 'wsrep_provider%' AND VARIABLE_NAME NOT IN (
+      'wsrep_provider',
+      'wsrep_provider_options',
+      'wsrep_provider_base_dir',
+      'wsrep_provider_base_port',
+      'wsrep_provider_gcache_dir',
+      'wsrep_provider_dbug',
+      'wsrep_provider_gcache_debug',
+      'wsrep_provider_signal',
+      'wsrep_provider_gmcast_listen_addr');
 
 --vertical_results
 SELECT * FROM INFORMATION_SCHEMA.SYSTEM_VARIABLES
@@ -14,5 +23,8 @@ WHERE VARIABLE_NAME LIKE 'wsrep_provider_%' AND VARIABLE_NAME NOT IN (
       'wsrep_provider_base_dir',
       'wsrep_provider_base_port',
       'wsrep_provider_gcache_dir',
+      'wsrep_provider_dbug',
+      'wsrep_provider_gcache_debug',
+      'wsrep_provider_signal',
       'wsrep_provider_gmcast_listen_addr')
 ORDER BY VARIABLE_NAME;

sql/wsrep_check_opts.cc

@@ -85,7 +85,7 @@ int wsrep_check_opts()
     }
   }
 
-  if (strcasecmp(wsrep_provider, "NONE"))
+  if (strcasecmp(wsrep_provider, WSREP_NONE))
   {
     if (global_system_variables.binlog_format != BINLOG_FORMAT_ROW)
     {

sql/wsrep_mysqld.cc

@@ -867,8 +867,8 @@ int wsrep_init()
   wsrep_init_position();
   wsrep_sst_auth_init();
 
-  if (strlen(wsrep_provider)== 0 ||
-      !strcmp(wsrep_provider, WSREP_NONE))
+  if (!*wsrep_provider ||
+      !strcasecmp(wsrep_provider, WSREP_NONE))
   {
     // enable normal operation in case no provider is specified
     global_system_variables.wsrep_on= 0;
@@ -922,7 +922,7 @@ int wsrep_init()
 
   /* Now WSREP is fully initialized */
   global_system_variables.wsrep_on= 1;
-  WSREP_ON_= wsrep_provider && strcmp(wsrep_provider, WSREP_NONE);
+  WSREP_ON_= wsrep_provider && *wsrep_provider && strcasecmp(wsrep_provider, WSREP_NONE);
   wsrep_service_started= 1;
 
   wsrep_init_provider_status_variables();
@@ -991,7 +991,8 @@ void wsrep_init_startup (bool sst_first)
     wsrep_plugins_pre_init();
 
   /* Skip replication start if dummy wsrep provider is loaded */
-  if (!strcmp(wsrep_provider, WSREP_NONE)) return;
+  if (!wsrep_provider || !*wsrep_provider ||
+      !strcasecmp(wsrep_provider, WSREP_NONE)) return;
 
   /* Skip replication start if no cluster address */
   if (!wsrep_cluster_address_exists()) return;

sql/wsrep_sst.cc

@@ -310,7 +310,8 @@ bool wsrep_sst_donor_update (sys_var *self, THD* thd, enum_var_type type)
 
 bool wsrep_before_SE()
 {
-  return (wsrep_provider != NULL
+  return (wsrep_provider
+          && *wsrep_provider
           && strcmp (wsrep_provider,   WSREP_NONE)
           && strcmp (wsrep_sst_method, WSREP_SST_SKIP)
           && strcmp (wsrep_sst_method, WSREP_SST_MYSQLDUMP));

sql/wsrep_var.cc

@@ -103,8 +103,8 @@ void wsrep_set_wsrep_on(THD* thd)
 {
   if (thd)
     thd->wsrep_was_on= WSREP_ON_;
-  WSREP_PROVIDER_EXISTS_= wsrep_provider &&
-    strncasecmp(wsrep_provider, WSREP_NONE, FN_REFLEN);
+  WSREP_PROVIDER_EXISTS_= wsrep_provider && *wsrep_provider &&
+    strcasecmp(wsrep_provider, WSREP_NONE);
   WSREP_ON_= global_system_variables.wsrep_on && WSREP_PROVIDER_EXISTS_;
 }
 
@@ -114,10 +114,14 @@ bool wsrep_on_update (sys_var *self, THD* thd, enum_var_type var_type)
   {
     my_bool saved_wsrep_on= global_system_variables.wsrep_on;
 
-    thd->variables.wsrep_on= global_system_variables.wsrep_on;
+    thd->variables.wsrep_on= saved_wsrep_on;
 
     // If wsrep has not been inited we need to do it now
-    if (global_system_variables.wsrep_on && wsrep_provider && !wsrep_inited)
+    if (!wsrep_inited &&
+        saved_wsrep_on &&
+        wsrep_provider &&
+        *wsrep_provider &&
+        strcasecmp(wsrep_provider, WSREP_NONE))
     {
       // wsrep_init() rewrites provide if it fails
       char* tmp= strdup(wsrep_provider);