Only count real users when checking for auto-creation of auto-join room

Previously if the first registered user was a "support" or "bot" user,
when the first real user registers, the auto-join rooms were not
created.

Fix to exclude non-real (ie users with a special user type) users
when counting how many users there are to determine whether we should
auto-create a room.

Signed-off-by: Jason Robinson <jasonr@matrix.org>

synapse/storage/registration.py

@@ -322,6 +322,21 @@ class RegistrationWorkerStore(SQLBaseStore):
 
         return None
 
+    @cachedInlineCallbacks()
+    def is_real_user(self, user_id):
+        """Determines if the user is a real user, ie does not have a 'user_type'.
+
+        Args:
+            user_id (str): user id to test
+
+        Returns:
+            Deferred[bool]: True if user 'user_type' is null or empty string
+        """
+        res = yield self.runInteraction(
+            "is_real_user", self.is_real_user_txn, user_id
+        )
+        return res
+
     @cachedInlineCallbacks()
     def is_support_user(self, user_id):
         """Determines if the user is of type UserTypes.SUPPORT
@@ -337,6 +352,16 @@ class RegistrationWorkerStore(SQLBaseStore):
         )
         return res
 
+    def is_real_user_txn(self, txn, user_id):
+        res = self._simple_select_one_onecol_txn(
+            txn=txn,
+            table="users",
+            keyvalues={"name": user_id},
+            retcol="user_type",
+            allow_none=True,
+        )
+        return True if res is None or res == "" else False
+
     def is_support_user_txn(self, txn, user_id):
         res = self._simple_select_one_onecol_txn(
             txn=txn,
@@ -421,6 +446,20 @@ class RegistrationWorkerStore(SQLBaseStore):
         ret = yield self.runInteraction("count_users", _count_users)
         return ret
 
+    @defer.inlineCallbacks
+    def count_real_users(self):
+        """Counts all users without a special user_type registered on the homeserver."""
+
+        def _count_users(txn):
+            txn.execute("SELECT COUNT(*) AS users FROM users where user_type is null or user_type = ''")
+            rows = self.cursor_to_dict(txn)
+            if rows:
+                return rows[0]["users"]
+            return 0
+
+        ret = yield self.runInteraction("count_real_users", _count_users)
+        return ret
+
     @defer.inlineCallbacks
     def find_next_generated_user_id_localpart(self):
         """