MDEV-24114 SHOW CREATE USER doesnt display correct password expiry status

Given PASSWORD EXPIRE and PASSWORD EXPIRE [NEVER|INTERVAL x DAY] are
two different mechanisms, SHOW CREATE USER should display all the
information required to restore the state of an account which
includes both a manual expired state and an automatic policy.

The solution proposed here keeps a CREATE USER ... PASSWORD EXPIRE
statement and adds an aditional
ALTER USER .. PASSWORD EXPIRE [NEVER|INTERVAL x DAY] when necessary

This way a tool can restore almost the complete state of an account
as it was before a dump. The only information left still is the
value of the password_last_changed column from mysql.global_priv

mysql-test/main/lock_user.result

@@ -156,6 +156,7 @@ alter user user1@localhost  PASSWORD EXPIRE NEVER ACCOUNT UNLOCK ;
 show create user user1@localhost;
 CREATE USER for user1@localhost
 CREATE USER `user1`@`localhost` PASSWORD EXPIRE
+ALTER USER `user1`@`localhost` PASSWORD EXPIRE NEVER
 alter user user1@localhost  ACCOUNT LOCK PASSWORD EXPIRE DEFAULT;
 show create user user1@localhost;
 CREATE USER for user1@localhost
@@ -167,5 +168,6 @@ localhost	user1	{"access":0,"plugin":"mysql_native_password","authentication_str
 show create user user1@localhost;
 CREATE USER for user1@localhost
 CREATE USER `user1`@`localhost` PASSWORD EXPIRE
+ALTER USER `user1`@`localhost` PASSWORD EXPIRE INTERVAL 60 DAY
 drop user user1@localhost;
 drop user user2@localhost;

mysql-test/main/password_expiration.result

@@ -125,6 +125,7 @@ alter user user1@localhost password expire;
 show create user user1@localhost;
 CREATE USER for user1@localhost
 CREATE USER `user1`@`localhost` PASSWORD EXPIRE
+ALTER USER `user1`@`localhost` PASSWORD EXPIRE INTERVAL 123 DAY
 set password for user1@localhost= password('');
 show create user user1@localhost;
 CREATE USER for user1@localhost
@@ -151,10 +152,12 @@ alter user user1@localhost password expire;
 show create user user1@localhost;
 CREATE USER for user1@localhost
 CREATE USER `user1`@`localhost` PASSWORD EXPIRE
+ALTER USER `user1`@`localhost` PASSWORD EXPIRE NEVER
 flush privileges;
 show create user user1@localhost;
 CREATE USER for user1@localhost
 CREATE USER `user1`@`localhost` PASSWORD EXPIRE
+ALTER USER `user1`@`localhost` PASSWORD EXPIRE NEVER
 set password for user1@localhost= password('');
 alter user user1@localhost password expire default;
 show create user user1@localhost;
@@ -184,10 +187,12 @@ alter user user1@localhost password expire;
 show create user user1@localhost;
 CREATE USER for user1@localhost
 CREATE USER `user1`@`localhost` PASSWORD EXPIRE
+ALTER USER `user1`@`localhost` PASSWORD EXPIRE NEVER
 flush privileges;
 show create user user1@localhost;
 CREATE USER for user1@localhost
 CREATE USER `user1`@`localhost` PASSWORD EXPIRE
+ALTER USER `user1`@`localhost` PASSWORD EXPIRE NEVER
 set global disconnect_on_expired_password=ON;
 connect(localhost,user1,,test,MYSQL_PORT,MYSQL_SOCK);
 connect con1,localhost,user1;

mysql-test/main/system_mysql_db_507.result

@@ -214,6 +214,7 @@ alter user user@localhost password expire;
 show create user user@localhost;
 CREATE USER for user@localhost
 CREATE USER `user`@`localhost` PASSWORD EXPIRE
+ALTER USER `user`@`localhost` PASSWORD EXPIRE INTERVAL 123 DAY
 set password for user@localhost= password('');
 show create user user@localhost;
 CREATE USER for user@localhost

sql/sql_acl.cc

@@ -8896,6 +8896,16 @@ static bool print_grants_for_role(THD *thd, ACL_ROLE * role)
 
 }
 
+static void append_auto_expiration_policy(ACL_USER *acl_user, String *r) {
+    if (!acl_user->password_lifetime)
+      r->append(STRING_WITH_LEN(" PASSWORD EXPIRE NEVER"));
+    else if (acl_user->password_lifetime > 0)
+    {
+      r->append(STRING_WITH_LEN(" PASSWORD EXPIRE INTERVAL "));
+      r->append_longlong(acl_user->password_lifetime);
+      r->append(STRING_WITH_LEN(" DAY"));
+    }
+}
 
 bool mysql_show_create_user(THD *thd, LEX_USER *lex_user)
 {
@@ -8955,14 +8965,8 @@ bool mysql_show_create_user(THD *thd, LEX_USER *lex_user)
 
   if (acl_user->password_expired)
     result.append(STRING_WITH_LEN(" PASSWORD EXPIRE"));
-  else if (!acl_user->password_lifetime)
-    result.append(STRING_WITH_LEN(" PASSWORD EXPIRE NEVER"));
-  else if (acl_user->password_lifetime > 0)
-  {
-    result.append(STRING_WITH_LEN(" PASSWORD EXPIRE INTERVAL "));
-    result.append_longlong(acl_user->password_lifetime);
-    result.append(STRING_WITH_LEN(" DAY"));
-  }
+  else
+    append_auto_expiration_policy(acl_user, &result);
 
   protocol->prepare_for_resend();
   protocol->store(result.ptr(), result.length(), result.charset());
@@ -8970,6 +8974,28 @@ bool mysql_show_create_user(THD *thd, LEX_USER *lex_user)
   {
     error= true;
   }
+
+  /* MDEV-24114 - PASSWORD EXPIRE and PASSWORD EXPIRE [NEVER | INTERVAL X DAY]
+   are two different mechanisms. To make sure a tool can restore the state
+   of a user account, including both the manual expiration state of the
+   account and the automatic expiration policy attached to it, we should
+   print two statements here, a CREATE USER (printed above) and an ALTER USER */
+  if (acl_user->password_expired && acl_user->password_lifetime > -1) {
+    result.length(0);
+    result.append("ALTER USER ");
+    append_identifier(thd, &result, username, strlen(username));
+    result.append('@');
+    append_identifier(thd, &result, acl_user->host.hostname,
+                      acl_user->hostname_length);
+    append_auto_expiration_policy(acl_user, &result);
+    protocol->prepare_for_resend();
+    protocol->store(result.ptr(), result.length(), result.charset());
+    if (protocol->write())
+    {
+      error= true;
+    }
+  }
+
   my_eof(thd);
 
 end: