branch-2.1: [fix](auth)Only treat admin@% and root@% as system users. #50904

fe/fe-core/src/main/java/org/apache/doris/analysis/UserIdentity.java

@@ -178,11 +178,11 @@ public static UserIdentity fromString(String userIdentStr) {
     }
 
     public boolean isRootUser() {
-        return user.equals(Auth.ROOT_USER);
+        return this.equals(ROOT);
     }
 
     public boolean isAdminUser() {
-        return user.equals(Auth.ADMIN_USER);
+        return this.equals(ADMIN);
     }
 
     public boolean isSystemUser() {

regression-test/suites/account_p0/test_system_user.groovy

@@ -62,4 +62,42 @@ suite("test_system_user","p0,auth") {
         revoke select_priv on *.*.* from  `admin`;
     """
 
+     sql """
+          create user `root`@'8.8.8.8';
+      """
+     sql """
+         grant select_priv on *.*.* to  `root`@'8.8.8.8';
+     """
+     sql """
+         revoke select_priv on *.*.* from  `root`@'8.8.8.8';
+     """
+     test {
+               sql """
+                   grant 'operator' to `root`@'8.8.8.8';
+               """
+               exception "Can not grant role: operator"
+         }
+    sql """
+            drop user `root`@'8.8.8.8';
+        """
+
+    sql """
+          create user `admin`@'8.8.8.8';
+      """
+     sql """
+         grant select_priv on *.*.* to  `admin`@'8.8.8.8';
+     """
+     sql """
+         revoke select_priv on *.*.* from  `admin`@'8.8.8.8';
+     """
+
+   sql """
+       grant 'admin' to `admin`@'8.8.8.8';
+   """
+    sql """
+           revoke 'admin' from `admin`@'8.8.8.8';
+       """
+    sql """
+            drop user `admin`@'8.8.8.8';
+        """
 }