models: Extract zerver.models.user_topics.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

zerver/models/__init__.py

@@ -3,7 +3,7 @@
 
 import hashlib
 import time
-from datetime import datetime, timedelta, timezone
+from datetime import timedelta
 from typing import Any, Callable, Dict, List, Optional, Tuple, TypedDict, TypeVar, Union
 
 import orjson
@@ -18,7 +18,7 @@ from django.core.serializers.json import DjangoJSONEncoder
 from django.db import models
 from django.db.backends.base.base import BaseDatabaseWrapper
 from django.db.models import CASCADE, Exists, F, OuterRef, Q, QuerySet
-from django.db.models.functions import Lower, Upper
+from django.db.models.functions import Upper
 from django.db.models.signals import post_delete, post_save
 from django.db.models.sql.compiler import SQLCompiler
 from django.utils.timezone import now as timezone_now
@@ -83,6 +83,7 @@ from zerver.models.streams import DefaultStream as DefaultStream
 from zerver.models.streams import DefaultStreamGroup as DefaultStreamGroup
 from zerver.models.streams import Stream as Stream
 from zerver.models.streams import Subscription as Subscription
+from zerver.models.user_topics import UserTopic as UserTopic
 from zerver.models.users import RealmUserDefault as RealmUserDefault
 from zerver.models.users import UserBaseSettings as UserBaseSettings
 from zerver.models.users import UserProfile as UserProfile
@@ -142,71 +143,6 @@ def query_for_ids(
     return query
 
 
-class UserTopic(models.Model):
-    user_profile = models.ForeignKey(UserProfile, on_delete=CASCADE)
-    stream = models.ForeignKey(Stream, on_delete=CASCADE)
-    recipient = models.ForeignKey(Recipient, on_delete=CASCADE)
-    topic_name = models.CharField(max_length=MAX_TOPIC_NAME_LENGTH)
-    # The default value for last_updated is a few weeks before tracking
-    # of when topics were muted was first introduced.  It's designed
-    # to be obviously incorrect so that one can tell it's backfilled data.
-    last_updated = models.DateTimeField(default=datetime(2020, 1, 1, 0, 0, tzinfo=timezone.utc))
-
-    class VisibilityPolicy(models.IntegerChoices):
-        # A normal muted topic. No notifications and unreads hidden.
-        MUTED = 1, "Muted topic"
-
-        # This topic will behave like an unmuted topic in an unmuted stream even if it
-        # belongs to a muted stream.
-        UNMUTED = 2, "Unmuted topic in muted stream"
-
-        # This topic will behave like `UNMUTED`, plus some additional
-        # display and/or notifications priority that is TBD and likely to
-        # be configurable; see #6027. Not yet implemented.
-        FOLLOWED = 3, "Followed topic"
-
-        # Implicitly, if a UserTopic does not exist, the (user, topic)
-        # pair should have normal behavior for that (user, stream) pair.
-
-        # We use this in our code to represent the condition in the comment above.
-        INHERIT = 0, "User's default policy for the stream."
-
-    visibility_policy = models.SmallIntegerField(
-        choices=VisibilityPolicy.choices, default=VisibilityPolicy.MUTED
-    )
-
-    class Meta:
-        constraints = [
-            models.UniqueConstraint(
-                "user_profile",
-                "stream",
-                Lower("topic_name"),
-                name="usertopic_case_insensitive_topic_uniq",
-            ),
-        ]
-
-        indexes = [
-            models.Index("stream", Upper("topic_name"), name="zerver_mutedtopic_stream_topic"),
-            # This index is designed to optimize queries fetching the
-            # set of users who have special policy for a stream,
-            # e.g. for the send-message code paths.
-            models.Index(
-                fields=("stream", "topic_name", "visibility_policy", "user_profile"),
-                name="zerver_usertopic_stream_topic_user_visibility_idx",
-            ),
-            # This index is useful for handling API requests fetching the
-            # muted topics for a given user or user/stream pair.
-            models.Index(
-                fields=("user_profile", "visibility_policy", "stream", "topic_name"),
-                name="zerver_usertopic_user_visibility_idx",
-            ),
-        ]
-
-    @override
-    def __str__(self) -> str:
-        return f"({self.user_profile.email}, {self.stream.name}, {self.topic_name}, {self.last_updated})"
-
-
 class MutedUser(models.Model):
     user_profile = models.ForeignKey(UserProfile, related_name="muter", on_delete=CASCADE)
     muted_user = models.ForeignKey(UserProfile, related_name="muted", on_delete=CASCADE)

zerver/models/user_topics.py

@@ -0,0 +1,76 @@
+from datetime import datetime, timezone
+
+from django.db import models
+from django.db.models import CASCADE
+from django.db.models.functions import Lower, Upper
+from typing_extensions import override
+
+from zerver.models.constants import MAX_TOPIC_NAME_LENGTH
+from zerver.models.recipients import Recipient
+from zerver.models.streams import Stream
+from zerver.models.users import UserProfile
+
+
+class UserTopic(models.Model):
+    user_profile = models.ForeignKey(UserProfile, on_delete=CASCADE)
+    stream = models.ForeignKey(Stream, on_delete=CASCADE)
+    recipient = models.ForeignKey(Recipient, on_delete=CASCADE)
+    topic_name = models.CharField(max_length=MAX_TOPIC_NAME_LENGTH)
+    # The default value for last_updated is a few weeks before tracking
+    # of when topics were muted was first introduced.  It's designed
+    # to be obviously incorrect so that one can tell it's backfilled data.
+    last_updated = models.DateTimeField(default=datetime(2020, 1, 1, 0, 0, tzinfo=timezone.utc))
+
+    class VisibilityPolicy(models.IntegerChoices):
+        # A normal muted topic. No notifications and unreads hidden.
+        MUTED = 1, "Muted topic"
+
+        # This topic will behave like an unmuted topic in an unmuted stream even if it
+        # belongs to a muted stream.
+        UNMUTED = 2, "Unmuted topic in muted stream"
+
+        # This topic will behave like `UNMUTED`, plus some additional
+        # display and/or notifications priority that is TBD and likely to
+        # be configurable; see #6027. Not yet implemented.
+        FOLLOWED = 3, "Followed topic"
+
+        # Implicitly, if a UserTopic does not exist, the (user, topic)
+        # pair should have normal behavior for that (user, stream) pair.
+
+        # We use this in our code to represent the condition in the comment above.
+        INHERIT = 0, "User's default policy for the stream."
+
+    visibility_policy = models.SmallIntegerField(
+        choices=VisibilityPolicy.choices, default=VisibilityPolicy.MUTED
+    )
+
+    class Meta:
+        constraints = [
+            models.UniqueConstraint(
+                "user_profile",
+                "stream",
+                Lower("topic_name"),
+                name="usertopic_case_insensitive_topic_uniq",
+            ),
+        ]
+
+        indexes = [
+            models.Index("stream", Upper("topic_name"), name="zerver_mutedtopic_stream_topic"),
+            # This index is designed to optimize queries fetching the
+            # set of users who have special policy for a stream,
+            # e.g. for the send-message code paths.
+            models.Index(
+                fields=("stream", "topic_name", "visibility_policy", "user_profile"),
+                name="zerver_usertopic_stream_topic_user_visibility_idx",
+            ),
+            # This index is useful for handling API requests fetching the
+            # muted topics for a given user or user/stream pair.
+            models.Index(
+                fields=("user_profile", "visibility_policy", "stream", "topic_name"),
+                name="zerver_usertopic_user_visibility_idx",
+            ),
+        ]
+
+    @override
+    def __str__(self) -> str:
+        return f"({self.user_profile.email}, {self.stream.name}, {self.topic_name}, {self.last_updated})"