Allow Guild.fetch_members to take in limit=None

Fixes #2473

discord/guild.py

@@ -633,7 +633,7 @@ class Guild(Hashable):
     @property
     def discovery_splash_url(self):
         """:class:`Asset`: Returns the guild's discovery splash asset.
-        
+
         .. versionadded:: 1.3.0
         """
         return self.discovery_splash_url_as()
@@ -1130,7 +1130,7 @@ class Guild(Hashable):
 
         return [convert(d) for d in data]
 
-    def fetch_members(self, *, limit=1, after=None):
+    def fetch_members(self, *, limit=1000, after=None):
         """|coro|
 
         Retrieves an :class:`.AsyncIterator` that enables receiving the guild's members.
@@ -1146,8 +1146,8 @@ class Guild(Hashable):
         Parameters
         ----------
         limit: Optional[:class:`int`]
-            The number of members to retrieve.
-            Defaults to 1.
+            The number of members to retrieve. Defaults to 1000.
+            Pass ``None`` to fetch all members. Note that this is potentially slow.
         after: Optional[Union[:class:`.abc.Snowflake`, :class:`datetime.datetime`]]
             Retrieve members after this date or object.
             If a date is provided it must be a timezone-naive datetime representing UTC time.

discord/iterators.py

@@ -589,7 +589,7 @@ class GuildIterator(_AsyncIterator):
         return data
 
 class MemberIterator(_AsyncIterator):
-    def __init__(self, guild, limit=1, after=None):
+    def __init__(self, guild, limit=1000, after=None):
 
         if isinstance(after, datetime.datetime):
             after = Object(id=time_snowflake(after, high=True))
@@ -611,16 +611,30 @@ class MemberIterator(_AsyncIterator):
         except asyncio.QueueEmpty:
             raise NoMoreItems()
 
+    def _get_retrieve(self):
+        l = self.limit
+        if l is None:
+            r = 1000
+        elif l <= 1000:
+            r = l
+        else:
+            r = 1000
+
+        self.retrieve = r
+        return r > 0
+
     async def fill_members(self):
-        if self.limit > 0:
-            retrieve = self.limit if self.limit <= 1000 else 1000
-
+        if self._get_retrieve():
             after = self.after.id if self.after else None
-            data = await self.get_members(self.guild.id, retrieve, after)
+            data = await self.get_members(self.guild.id, self.retrieve, after)
+            if not data:
+                # no data, terminate
+                return
 
-            if data:
-                self.limit -= retrieve
-                self.after = Object(id=int(data[-1]['user']['id']))
+            if len(data) < 1000:
+                self.limit = 0 # terminate loop
+
+            self.after = Object(id=int(data[-1]['user']['id']))
 
             for element in reversed(data):
                 await self.members.put(self.create_member(element))