message_send: Remove TypeGuard.

The type safety of a TypeGuard is unchecked by mypy.  While this
particular TypeGuard is safe given the current context, one could
imagine future changes that make it unsafe, so it’s preferable to
avoid unchecked constructs whenever possible.

Signed-off-by: Anders Kaseorg <[email protected]>

zerver/actions/message_send.py

@@ -9,7 +9,6 @@
     Collection,
     Dict,
     List,
-    Literal,
     Optional,
     Sequence,
     Set,
@@ -27,7 +26,6 @@
 from django.utils.timezone import now as timezone_now
 from django.utils.translation import gettext as _
 from django.utils.translation import override as override_language
-from typing_extensions import TypeGuard
 
 from zerver.actions.uploads import do_claim_attachments
 from zerver.lib.addressee import Addressee
@@ -171,24 +169,16 @@ class RecipientInfoResult(TypedDict):
     all_bot_user_ids: Set[int]
 
 
-class BaseActiveUserDict(TypedDict):
+class ActiveUserDict(TypedDict):
     id: int
     enable_online_push_notifications: bool
     enable_offline_email_notifications: bool
     enable_offline_push_notifications: bool
     long_term_idle: bool
-
-
-class ActiveUserDict(BaseActiveUserDict):
     is_bot: bool
     bot_type: Optional[int]
 
 
-class ActiveBotUserDict(BaseActiveUserDict):
-    is_bot: Literal[True]
-    bot_type: int
-
-
 def get_recipient_info(
     *,
     realm_id: int,
@@ -343,9 +333,6 @@ def get_ids_for(f: Callable[[ActiveUserDict], bool]) -> Set[int]:
         """Only includes users on the explicit message to line"""
         return {row["id"] for row in rows if f(row)} & message_to_user_id_set
 
-    def is_service_bot(row: ActiveUserDict) -> TypeGuard[ActiveBotUserDict]:
-        return row["is_bot"] and (row["bot_type"] in UserProfile.SERVICE_BOT_TYPES)
-
     active_user_ids = get_ids_for(lambda r: True)
     online_push_user_ids = get_ids_for(
         lambda r: r["enable_online_push_notifications"],
@@ -363,7 +350,7 @@ def is_service_bot(row: ActiveUserDict) -> TypeGuard[ActiveBotUserDict]:
 
     # Service bots don't get UserMessage rows.
     um_eligible_user_ids = get_ids_for(
-        lambda r: not is_service_bot(r),
+        lambda r: not r["is_bot"] or r["bot_type"] not in UserProfile.SERVICE_BOT_TYPES,
     )
 
     long_term_idle_user_ids = get_ids_for(
@@ -384,7 +371,11 @@ def is_service_bot(row: ActiveUserDict) -> TypeGuard[ActiveBotUserDict]:
         row["id"] for row in rows if row["is_bot"] and row["bot_type"] == UserProfile.DEFAULT_BOT
     }
 
-    service_bot_tuples = [(row["id"], row["bot_type"]) for row in rows if is_service_bot(row)]
+    service_bot_tuples = [
+        (row["id"], row["bot_type"])
+        for row in rows
+        if row["is_bot"] and row["bot_type"] in UserProfile.SERVICE_BOT_TYPES
+    ]
 
     # We also need the user IDs of all bots, to avoid trying to send push/email
     # notifications to them. This set will be directly sent to the event queue code