python: Rewrite dict() as {}.

Suggested by the flake8-comprehensions plugin.

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

scripts/lib/check_rabbitmq_queue.py

@@ -155,7 +155,7 @@ def check_rabbitmq_queues() -> None:
     list_consumers_output = subprocess.check_output(['/usr/sbin/rabbitmqctl', 'list_consumers'],
                                                     universal_newlines=True)
 
-    queue_counts_rabbitmqctl = dict()
+    queue_counts_rabbitmqctl = {}
     for line in list_queues_output.split("\n"):
         line = line.strip()
         m = pattern.match(line)
@@ -176,7 +176,7 @@ def check_rabbitmq_queues() -> None:
     queue_stats_dir = subprocess.check_output([os.path.join(ZULIP_PATH, 'scripts/get-django-setting'),
                                                'QUEUE_STATS_DIR'],
                                               universal_newlines=True).strip()
-    queue_stats: Dict[str, Dict[str, Any]] = dict()
+    queue_stats: Dict[str, Dict[str, Any]] = {}
     queues_to_check = set(normal_queues).intersection(set(queues_with_consumers))
     for queue in queues_to_check:
         fn = queue + ".stats"

tools/create-test-api-docs

@@ -124,7 +124,7 @@ def create_user_docs() -> None:
             ('json', 'legacy'),
         ]
 
-        groups: Dict[str, Set[str]] = dict()
+        groups: Dict[str, Set[str]] = {}
         for prefix, name in tups:
             groups[name] = {p for p in patterns if p.startswith(prefix)}
             patterns -= groups[name]

zerver/data_import/hipchat.py

@@ -661,7 +661,7 @@ def process_raw_message_batch(realm_id: int,
         content = content.replace('@here', '@**all**')
         return content
 
-    mention_map: Dict[int, Set[int]] = dict()
+    mention_map: Dict[int, Set[int]] = {}
 
     zerver_message = []
 

zerver/data_import/hipchat_attachment.py

@@ -8,7 +8,7 @@ from zerver.data_import.import_util import build_attachment, create_converted_da
 
 class AttachmentHandler:
     def __init__(self) -> None:
-        self.info_dict: Dict[str, Dict[str, Any]] = dict()
+        self.info_dict: Dict[str, Dict[str, Any]] = {}
 
     def handle_message_data(self,
                             realm_id: int,

zerver/data_import/hipchat_user.py

@@ -20,8 +20,8 @@ class UserHandler:
     '''
 
     def __init__(self) -> None:
-        self.id_to_user_map: Dict[int, Dict[str, Any]] = dict()
+        self.id_to_user_map: Dict[int, Dict[str, Any]] = {}
-        self.name_to_mirror_user_map: Dict[str, Dict[str, Any]] = dict()
+        self.name_to_mirror_user_map: Dict[str, Dict[str, Any]] = {}
         self.mirror_user_id = 1
 
     def add_user(self, user: Dict[str, Any]) -> None:

zerver/data_import/import_util.py

@@ -41,8 +41,8 @@ ZerverFieldsT = Dict[str, Any]
 
 class SubscriberHandler:
     def __init__(self) -> None:
-        self.stream_info: Dict[int, Set[int]] = dict()
+        self.stream_info: Dict[int, Set[int]] = {}
-        self.huddle_info: Dict[int, Set[int]] = dict()
+        self.huddle_info: Dict[int, Set[int]] = {}
 
     def set_info(self,
                  users: Set[int],
@@ -129,7 +129,7 @@ def make_subscriber_map(zerver_subscription: List[ZerverFieldsT]) -> Dict[int, S
     This can be convenient for building up UserMessage
     rows.
     '''
-    subscriber_map: Dict[int, Set[int]] = dict()
+    subscriber_map: Dict[int, Set[int]] = {}
     for sub in zerver_subscription:
         user_id = sub['user_profile']
         recipient_id = sub['recipient']

zerver/data_import/mattermost.py

@@ -319,7 +319,7 @@ def process_raw_message_batch(realm_id: int,
         content = content.replace('@here', '@**all**')
         return content
 
-    mention_map: Dict[int, Set[int]] = dict()
+    mention_map: Dict[int, Set[int]] = {}
     zerver_message = []
 
     import html2text

zerver/data_import/mattermost_user.py

@@ -12,7 +12,7 @@ class UserHandler:
     '''
 
     def __init__(self) -> None:
-        self.id_to_user_map: Dict[int, Dict[str, Any]] = dict()
+        self.id_to_user_map: Dict[int, Dict[str, Any]] = {}
 
     def add_user(self, user: Dict[str, Any]) -> None:
         user_id = user['id']

zerver/data_import/sequencer.py

@@ -28,7 +28,7 @@ def sequencer() -> Callable[[str], int]:
         NEXT_ID = sequencer()
         message_id = NEXT_ID('message')
     '''
-    seq_dict: Dict[str, Callable[[], int]] = dict()
+    seq_dict: Dict[str, Callable[[], int]] = {}
 
     def next_one(name: str) -> int:
         if name not in seq_dict:
@@ -59,7 +59,7 @@ def is_int(key: Any) -> bool:
 
 class IdMapper:
     def __init__(self) -> None:
-        self.map: Dict[Any, int] = dict()
+        self.map: Dict[Any, int] = {}
         self.cnt = 0
 
     def has(self, their_id: Any) -> bool:

zerver/lib/alert_words.py

@@ -15,7 +15,7 @@ from zerver.models import AlertWord, Realm, UserProfile, flush_realm_alert_words
 def alert_words_in_realm(realm: Realm) -> Dict[int, List[str]]:
     user_ids_and_words = AlertWord.objects.filter(
         realm=realm, user_profile__is_active=True).values("user_profile_id", "word")
-    user_ids_with_words: Dict[int, List[str]] = dict()
+    user_ids_with_words: Dict[int, List[str]] = {}
     for id_and_word in user_ids_and_words:
         user_ids_with_words.setdefault(id_and_word["user_profile_id"], [])
         user_ids_with_words[id_and_word["user_profile_id"]].append(id_and_word["word"])

zerver/lib/bot_config.py

@@ -68,4 +68,4 @@ def load_bot_config_template(bot: str) -> Dict[str, str]:
             config.read_file(conf)
         return dict(config.items(bot))
     else:
-        return dict()
+        return {}

zerver/lib/bot_lib.py

@@ -125,7 +125,7 @@ class EmbeddedBotHandler:
             return get_bot_config(self.user_profile)
         except ConfigError:
             if optional:
-                return dict()
+                return {}
             raise
 
     def quit(self, message: str= "") -> None:

zerver/lib/events.py

@@ -810,7 +810,7 @@ def apply_event(state: Dict[str, Any],
         status_text = event.get('status_text')
 
         if user_id_str not in user_status:
-            user_status[user_id_str] = dict()
+            user_status[user_id_str] = {}
 
         if away is not None:
             if away:

zerver/lib/markdown/__init__.py

@@ -754,7 +754,7 @@ class InlineInterestingLinkProcessor(markdown.treeprocessors.Treeprocessor):
             # and gifs do not work.
             # TODO: What if image is huge? Should we get headers first?
             if image_info is None:
-                image_info = dict()
+                image_info = {}
             image_info['is_image'] = True
             parsed_url_list = list(parsed_url)
             parsed_url_list[4] = "dl=1"  # Replaces query
@@ -2217,7 +2217,7 @@ class MentionData:
 
 def get_user_group_name_info(realm_id: int, user_group_names: Set[str]) -> Dict[str, UserGroup]:
     if not user_group_names:
-        return dict()
+        return {}
 
     rows = UserGroup.objects.filter(realm_id=realm_id,
                                     name__in=user_group_names)
@@ -2226,7 +2226,7 @@ def get_user_group_name_info(realm_id: int, user_group_names: Set[str]) -> Dict[
 
 def get_stream_name_info(realm: Realm, stream_names: Set[str]) -> Dict[str, FullNameInfo]:
     if not stream_names:
-        return dict()
+        return {}
 
     q_list = {
         Q(name=name)
@@ -2323,7 +2323,7 @@ def do_convert(content: str,
         if content_has_emoji_syntax(content):
             active_realm_emoji = message_realm.get_active_emoji()
         else:
-            active_realm_emoji = dict()
+            active_realm_emoji = {}
 
         _md_engine.zulip_db_data = {
             'realm_alert_words_automaton': realm_alert_words_automaton,

zerver/lib/message.py

@@ -730,7 +730,7 @@ def huddle_users(recipient_id: int) -> str:
 def aggregate_message_dict(input_dict: Dict[int, Dict[str, Any]],
                            lookup_fields: List[str],
                            collect_senders: bool) -> List[Dict[str, Any]]:
-    lookup_dict: Dict[Tuple[Any, ...], Dict[str, Any]] = dict()
+    lookup_dict: Dict[Tuple[Any, ...], Dict[str, Any]] = {}
 
     '''
     A concrete example might help explain the inputs here:

zerver/lib/presence.py

@@ -33,7 +33,7 @@ def get_status_dicts_for_rows(all_rows: List[Dict[str, Any]],
         get_user_key = lambda row: row['user_profile__email']
         get_user_info = get_legacy_user_info
 
-    user_statuses: Dict[str, Dict[str, Any]] = dict()
+    user_statuses: Dict[str, Dict[str, Any]] = {}
 
     for user_key, presence_rows in itertools.groupby(all_rows, get_user_key):
         info = get_user_info(
@@ -64,7 +64,7 @@ def get_modern_user_info(presence_rows: List[Dict[str, Any]],
     # Be stingy about bandwidth, and don't even include
     # keys for entities that have None values.  JS
     # code should just do a falsy check here.
-    result = dict()
+    result = {}
 
     if active_timestamp is not None:
         result['active_timestamp'] = active_timestamp
@@ -100,7 +100,7 @@ def get_legacy_user_info(presence_rows: List[Dict[str, Any]],
 
     most_recent_info = info_rows[-1]
 
-    result = dict()
+    result = {}
 
     # The word "aggegrated" here is possibly misleading.
     # It's really just the most recent client's info.

zerver/lib/stream_recipient.py

@@ -21,8 +21,8 @@ class StreamRecipientMap:
     '''
 
     def __init__(self) -> None:
-        self.recip_to_stream: Dict[int, int] = dict()
+        self.recip_to_stream: Dict[int, int] = {}
-        self.stream_to_recip: Dict[int, int] = dict()
+        self.stream_to_recip: Dict[int, int] = {}
 
     def populate_with(self, *, stream_id: int, recipient_id: int) -> None:
         # We use * to enforce using named arguments when calling this function,

zerver/lib/user_status.py

@@ -19,13 +19,13 @@ def get_user_info_dict(realm_id: int) -> Dict[str, Dict[str, Any]]:
         'status_text',
     )
 
-    user_dict: Dict[str, Dict[str, Any]] = dict()
+    user_dict: Dict[str, Dict[str, Any]] = {}
     for row in rows:
         away = row['status'] == UserStatus.AWAY
         status_text = row['status_text']
         user_id = row['user_profile_id']
 
-        dct = dict()
+        dct = {}
         if away:
             dct['away'] = away
         if status_text:

zerver/lib/zcommand.py

@@ -25,7 +25,7 @@ def process_zcommands(content: str, user_profile: UserProfile) -> Dict[str, Any]
     command = content[1:]
 
     if command == 'ping':
-        return dict()
+        return {}
     elif command == 'night':
         if user_profile.color_scheme == UserProfile.COLOR_SCHEME_NIGHT:
             return dict(msg='You are still in night mode.')

zerver/middleware.py

@@ -239,7 +239,7 @@ class LogRequests(MiddlewareMixin):
             # Avoid re-initializing request._log_data if it's already there.
             return
 
-        request._log_data = dict()
+        request._log_data = {}
         record_request_start_data(request._log_data)
 
     def process_view(self, request: HttpRequest, view_func: ViewFuncT,

zerver/migrations/0224_alter_field_realm_video_chat_provider.py

@@ -30,7 +30,7 @@ def get_video_chat_provider_detail(providers_dict: Dict[str, Dict[str, Any]],
             return provider
         if (p_id and provider['id'] == p_id):
             return provider
-    return dict()
+    return {}
 
 def update_existing_video_chat_provider_values(apps: StateApps, schema_editor: DatabaseSchemaEditor) -> None:
     Realm = apps.get_model('zerver', 'Realm')

zerver/migrations/0277_migrate_alert_word.py

@@ -28,7 +28,7 @@ def move_back_to_user_profile(apps: StateApps, schema_editor: DatabaseSchemaEdit
     UserProfile = apps.get_model('zerver', 'UserProfile')
 
     user_ids_and_words = AlertWord.objects.all().values("user_profile_id", "word")
-    user_ids_with_words: Dict[int, List[str]] = dict()
+    user_ids_with_words: Dict[int, List[str]] = {}
 
     for id_and_word in user_ids_and_words:
         user_ids_with_words.setdefault(id_and_word["user_profile_id"], [])

zerver/openapi/curl_param_value_generators.py

@@ -8,7 +8,7 @@ from zerver.lib.events import do_events_register
 from zerver.lib.test_classes import ZulipTestCase
 from zerver.models import Client, Message, UserGroup, UserPresence, get_realm
 
-GENERATOR_FUNCTIONS: Dict[str, Callable[[], Dict[str, object]]] = dict()
+GENERATOR_FUNCTIONS: Dict[str, Callable[[], Dict[str, object]]] = {}
 REGISTERED_GENERATOR_FUNCTIONS: Set[str] = set()
 CALLED_GENERATOR_FUNCTIONS: Set[str] = set()
 

zerver/openapi/markdown_extension.py

@@ -306,7 +306,7 @@ def render_curl_example(function: str, api_url: str,
     parts = function.split(":")
     endpoint = parts[0]
     method = parts[1]
-    kwargs: Dict[str, Any] = dict()
+    kwargs: Dict[str, Any] = {}
     if len(parts) > 2:
         kwargs["auth_email"] = parts[2]
     if len(parts) > 3:

zerver/openapi/openapi.py

@@ -266,7 +266,7 @@ def validate_schema(schema: Dict[str, Any]) -> None:
         if 'additionalProperties' not in schema:
             raise SchemaError('additionalProperties needs to be defined for objects to make' +
                               'sure they have no additional properties left to be documented.')
-        for property_schema in schema.get('properties', dict()).values():
+        for property_schema in schema.get('properties', {}).values():
             validate_schema(property_schema)
         if schema['additionalProperties']:
             validate_schema(schema['additionalProperties'])

zerver/openapi/python_examples.py

@@ -12,7 +12,7 @@ from zerver.openapi.openapi import validate_against_openapi_schema
 
 ZULIP_DIR = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
-TEST_FUNCTIONS: Dict[str, Callable[..., object]] = dict()
+TEST_FUNCTIONS: Dict[str, Callable[..., object]] = {}
 REGISTERED_TEST_FUNCTIONS: Set[str] = set()
 CALLED_TEST_FUNCTIONS: Set[str] = set()
 

zerver/tests/test_auth_backends.py

@@ -255,23 +255,23 @@ class AuthBackendTest(ZulipTestCase):
                                              password=password,
                                              username=username,
                                              realm=get_realm('zulip'),
-                                             return_data=dict()),
+                                             return_data={}),
                             bad_kwargs=dict(request=mock.MagicMock(),
                                             password=password,
                                             username=username,
                                             realm=get_realm('zephyr'),
-                                            return_data=dict()))
+                                            return_data={}))
         self.verify_backend(EmailAuthBackend(),
                             good_kwargs=dict(request=mock.MagicMock(),
                                              password=password,
                                              username=username,
                                              realm=get_realm('zulip'),
-                                             return_data=dict()),
+                                             return_data={}),
                             bad_kwargs=dict(request=mock.MagicMock(),
                                             password=password,
                                             username=username,
                                             realm=get_realm('zephyr'),
-                                            return_data=dict()))
+                                            return_data={}))
 
     def test_email_auth_backend_empty_password(self) -> None:
         user_profile = self.example_user('hamlet')
@@ -600,7 +600,7 @@ class RateLimitAuthenticationTests(ZulipTestCase):
                                                    username=username,
                                                    realm=get_realm("zulip"),
                                                    password=password,
-                                                   return_data=dict())
+                                                   return_data={})
 
         self.do_test_auth_rate_limiting(attempt_authentication,
                                         user_profile.delivery_email,
@@ -619,7 +619,7 @@ class RateLimitAuthenticationTests(ZulipTestCase):
                                                        username=username,
                                                        realm=get_realm("zulip"),
                                                        password=password,
-                                                       return_data=dict())
+                                                       return_data={})
 
         self.do_test_auth_rate_limiting(attempt_authentication,
                                         user_profile.delivery_email,
@@ -643,7 +643,7 @@ class RateLimitAuthenticationTests(ZulipTestCase):
                                 username=username,
                                 realm=get_realm("zulip"),
                                 password=password,
-                                return_data=dict())
+                                return_data={})
 
         self.do_test_auth_rate_limiting(attempt_authentication,
                                         user_profile.delivery_email,

zerver/tests/test_docs.py

@@ -274,7 +274,7 @@ class IntegrationTest(ZulipTestCase):
             self.assertTrue(os.path.isfile(settings.DEPLOY_ROOT + path), integration.name)
 
     def test_api_url_view_subdomains_base(self) -> None:
-        context: Dict[str, Any] = dict()
+        context: Dict[str, Any] = {}
         add_api_uri_context(context, HostRequestMock())
         self.assertEqual(context["api_url_scheme_relative"], "testserver/api")
         self.assertEqual(context["api_url"], "http://testserver/api")
@@ -282,14 +282,14 @@ class IntegrationTest(ZulipTestCase):
 
     @override_settings(ROOT_DOMAIN_LANDING_PAGE=True)
     def test_api_url_view_subdomains_homepage_base(self) -> None:
-        context: Dict[str, Any] = dict()
+        context: Dict[str, Any] = {}
         add_api_uri_context(context, HostRequestMock())
         self.assertEqual(context["api_url_scheme_relative"], "yourZulipDomain.testserver/api")
         self.assertEqual(context["api_url"], "http://yourZulipDomain.testserver/api")
         self.assertFalse(context["html_settings_links"])
 
     def test_api_url_view_subdomains_full(self) -> None:
-        context: Dict[str, Any] = dict()
+        context: Dict[str, Any] = {}
         request = HostRequestMock(host="mysubdomain.testserver")
         add_api_uri_context(context, request)
         self.assertEqual(context["api_url_scheme_relative"], "mysubdomain.testserver/api")
@@ -297,7 +297,7 @@ class IntegrationTest(ZulipTestCase):
         self.assertTrue(context["html_settings_links"])
 
     def test_html_settings_links(self) -> None:
-        context: Dict[str, Any] = dict()
+        context: Dict[str, Any] = {}
         with self.settings(ROOT_DOMAIN_LANDING_PAGE=True):
             add_api_uri_context(context, HostRequestMock())
         self.assertEqual(
@@ -307,7 +307,7 @@ class IntegrationTest(ZulipTestCase):
             context['subscriptions_html'],
             'streams page')
 
-        context = dict()
+        context = {}
         with self.settings(ROOT_DOMAIN_LANDING_PAGE=True):
             add_api_uri_context(context, HostRequestMock(host="mysubdomain.testserver"))
         self.assertEqual(
@@ -317,7 +317,7 @@ class IntegrationTest(ZulipTestCase):
             context['subscriptions_html'],
             '<a target="_blank" href="/#streams">streams page</a>')
 
-        context = dict()
+        context = {}
         add_api_uri_context(context, HostRequestMock())
         self.assertEqual(
             context['settings_html'],

zerver/tests/test_message_edit.py

@@ -47,7 +47,7 @@ class EditMessageTest(ZulipTestCase):
             (fetch_message_dict,) = messages_for_ids(
                 message_ids = [msg.id],
                 user_message_flags={msg_id: []},
-                search_fields=dict(),
+                search_fields={},
                 apply_markdown=False,
                 client_gravatar=False,
                 allow_edit_history=True,

zerver/tests/test_message_fetch.py

@@ -1151,7 +1151,7 @@ class GetOldMessagesTest(ZulipTestCase):
         Test old `/json/messages` returns reactions.
         """
         self.login('hamlet')
-        messages = self.get_and_check_messages(dict())
+        messages = self.get_and_check_messages({})
         message_id = messages['messages'][0]['id']
 
         self.login('othello')
@@ -1182,7 +1182,7 @@ class GetOldMessagesTest(ZulipTestCase):
         messages.
         """
         self.login('hamlet')
-        self.get_and_check_messages(dict())
+        self.get_and_check_messages({})
 
         othello_email = self.example_user('othello').email
 

zerver/tests/test_message_flags.py

@@ -507,7 +507,7 @@ class GetUnreadMsgsTest(ZulipTestCase):
             self.subscribe(cordelia, stream_name)
 
         all_message_ids: Set[int] = set()
-        message_ids = dict()
+        message_ids = {}
 
         tups = [
             ('social', 'lunch'),

zerver/tests/test_message_topics.py

@@ -21,7 +21,7 @@ class TopicHistoryTest(ZulipTestCase):
         self.login_user(user_profile)
         self.subscribe(user_profile, stream_name)
         endpoint = f'/json/users/me/{stream.id}/topics'
-        result = self.client_get(endpoint, dict(), subdomain="zephyr")
+        result = self.client_get(endpoint, {}, subdomain="zephyr")
         self.assert_json_success(result)
         history = result.json()['topics']
         self.assertEqual(history, [])
@@ -75,7 +75,7 @@ class TopicHistoryTest(ZulipTestCase):
         topic0_msg_id = create_test_message('topic0')
 
         endpoint = f'/json/users/me/{stream.id}/topics'
-        result = self.client_get(endpoint, dict())
+        result = self.client_get(endpoint, {})
         self.assert_json_success(result)
         history = result.json()['topics']
 
@@ -99,7 +99,7 @@ class TopicHistoryTest(ZulipTestCase):
         # that she doesn't have UserMessage rows.  We should see the
         # same results for a public stream.
         self.login('cordelia')
-        result = self.client_get(endpoint, dict())
+        result = self.client_get(endpoint, {})
         self.assert_json_success(result)
         history = result.json()['topics']
 
@@ -124,7 +124,7 @@ class TopicHistoryTest(ZulipTestCase):
         do_change_stream_invite_only(stream, True)
         self.subscribe(self.example_user("cordelia"), stream.name)
 
-        result = self.client_get(endpoint, dict())
+        result = self.client_get(endpoint, {})
         self.assert_json_success(result)
         history = result.json()['topics']
         history = history[:3]
@@ -140,7 +140,7 @@ class TopicHistoryTest(ZulipTestCase):
 
         # non-sensible stream id
         endpoint = '/json/users/me/9999999999/topics'
-        result = self.client_get(endpoint, dict())
+        result = self.client_get(endpoint, {})
         self.assert_json_error(result, 'Invalid stream id')
 
         # out of realm
@@ -149,7 +149,7 @@ class TopicHistoryTest(ZulipTestCase):
             realm=get_realm('zephyr'),
         )
         endpoint = f'/json/users/me/{bad_stream.id}/topics'
-        result = self.client_get(endpoint, dict())
+        result = self.client_get(endpoint, {})
         self.assert_json_error(result, 'Invalid stream id')
 
         # private stream to which I am not subscribed
@@ -158,7 +158,7 @@ class TopicHistoryTest(ZulipTestCase):
             invite_only=True,
         )
         endpoint = f'/json/users/me/{private_stream.id}/topics'
-        result = self.client_get(endpoint, dict())
+        result = self.client_get(endpoint, {})
         self.assert_json_error(result, 'Invalid stream id')
 
 class TopicDeleteTest(ZulipTestCase):

zerver/tests/test_mirror_users.py

@@ -19,7 +19,7 @@ class MirroredMessageUsersTest(ZulipTestCase):
         recipients: List[str] = []
 
         Request = namedtuple('Request', ['POST'])
-        request = Request(POST=dict())  # no sender
+        request = Request(POST={})  # no sender
 
         with self.assertRaises(InvalidMirrorInput):
             create_mirrored_message_users(request, user, recipients)

zerver/tests/test_openapi.py

@@ -433,7 +433,7 @@ do not match the types declared in the implementation of {function.__name__}.\n"
         Otherwise, we print out the exact differences for convenient debugging and raise an
         AssertionError. """
         openapi_params: Set[Tuple[str, Union[type, Tuple[type, object]]]] = set()
-        json_params: Dict[str, Union[type, Tuple[type, object]]] = dict()
+        json_params: Dict[str, Union[type, Tuple[type, object]]] = {}
         for element in openapi_parameters:
             name: str = element["name"]
             schema = {}

zerver/tests/test_outgoing_webhook_interfaces.py

@@ -137,7 +137,7 @@ class TestGenericOutgoingWebhookService(ZulipTestCase):
         )
         self.assertEqual(success_response, expected_response)
 
-        response = dict()
+        response = {}
         success_response = self.handler.process_success(response)
         self.assertEqual(success_response, None)
 

zerver/tests/test_service_bot_system.py

@@ -343,7 +343,7 @@ class TestServiceBotConfigHandler(ZulipTestCase):
         with self.assertRaises(ConfigError):
             self.bot_handler.get_config_info('foo')
 
-        self.assertEqual(self.bot_handler.get_config_info('foo', optional=True), dict())
+        self.assertEqual(self.bot_handler.get_config_info('foo', optional=True), {})
 
         config_dict = {"entry 1": "value 1", "entry 2": "value 2"}
         for key, value in config_dict.items():

zerver/tests/test_signup.py

@@ -759,7 +759,7 @@ class LoginTest(ZulipTestCase):
         self.assertEqual(response["Location"], "http://zulip.testserver")
 
     def test_start_two_factor_auth(self) -> None:
-        request = MagicMock(POST=dict())
+        request = MagicMock(POST={})
         with patch('zerver.views.auth.TwoFactorLoginView') as mock_view:
             mock_view.as_view.return_value = lambda *a, **k: HttpResponse()
             response = start_two_factor_auth(request)

zerver/tests/test_slack_importer.py

@@ -627,7 +627,7 @@ class SlackImporter(ZulipTestCase):
         dm_members = {'DJ47BL849': ('U066MTL5U', 'U061A5N1G'), 'DHX1UP7EG': ('U061A5N1G', 'U061A1R2R')}
 
         zerver_usermessage: List[Dict[str, Any]] = []
-        subscriber_map: Dict[int, Set[int]] = dict()
+        subscriber_map: Dict[int, Set[int]] = {}
         added_channels: Dict[str, Tuple[str, int]] = {'random': ('c5', 1), 'general': ('c6', 2)}
 
         zerver_message, zerver_usermessage, attachment, uploads, reaction = \

zerver/tests/test_user_status.py

@@ -19,7 +19,7 @@ def get_away_user_ids(realm_id: int) -> Set[int]:
 
 def user_info(user: UserProfile) -> Dict[str, Any]:
     user_dict = get_user_info_dict(user.realm_id)
-    return user_dict.get(str(user.id), dict())
+    return user_dict.get(str(user.id), {})
 
 class UserStatusTest(ZulipTestCase):
     def test_basics(self) -> None:
@@ -92,7 +92,7 @@ class UserStatusTest(ZulipTestCase):
 
         self.assertEqual(
             user_info(hamlet),
-            dict(),
+            {},
         )
 
         away_user_ids = get_away_user_ids(realm_id=realm_id)
@@ -148,7 +148,7 @@ class UserStatusTest(ZulipTestCase):
         self.login_user(hamlet)
 
         # Try to omit parameter--this should be an error.
-        payload: Dict[str, Any] = dict()
+        payload: Dict[str, Any] = {}
         result = self.client_post('/json/users/me/status', payload)
         self.assert_json_error(result, "Client did not pass any new values.")
 

zerver/tests/test_users.py

@@ -768,7 +768,7 @@ class AdminCreateUserTest(ZulipTestCase):
         self.login_user(admin)
         do_change_user_role(admin, UserProfile.ROLE_REALM_ADMINISTRATOR)
 
-        result = self.client_post("/json/users", dict())
+        result = self.client_post("/json/users", {})
         self.assert_json_error(result, "Missing 'email' argument")
 
         result = self.client_post("/json/users", dict(

zerver/tests/test_widgets.py

@@ -31,7 +31,7 @@ class WidgetContentTestCase(ZulipTestCase):
         assert_error(dict(widget_type='bogus', extra_data={}),
                      'unknown widget type: bogus')
 
-        extra_data: Dict[str, Any] = dict()
+        extra_data: Dict[str, Any] = {}
         obj = dict(widget_type='zform', extra_data=extra_data)
 
         assert_error(obj, 'zform is missing type field')

zerver/tornado/event_queue.py

@@ -687,7 +687,7 @@ def maybe_enqueue_notifications(user_profile_id: int, message_id: int, private_m
     """This function has a complete unit test suite in
     `test_enqueue_notifications` that should be expanded as we add
     more features here."""
-    notified: Dict[str, bool] = dict()
+    notified: Dict[str, bool] = {}
 
     if (idle or always_push_notify) and (private_message or mentioned or
                                          wildcard_mention_notify or stream_push_notify):

zerver/views/message_fetch.py

@@ -1024,7 +1024,7 @@ def get_messages_backend(request: HttpRequest,
             user_message_flags[message_id] = UserMessage.flags_list_for_flags(flags)
             message_ids.append(message_id)
 
-    search_fields: Dict[int, Dict[str, str]] = dict()
+    search_fields: Dict[int, Dict[str, str]] = {}
     if is_search:
         for row in rows:
             message_id = row[0]
@@ -1231,7 +1231,7 @@ def messages_in_narrow_backend(request: HttpRequest, user_profile: UserProfile,
     sa_conn = get_sqlalchemy_connection()
     query_result = list(sa_conn.execute(query).fetchall())
 
-    search_fields = dict()
+    search_fields = {}
     for row in query_result:
         message_id = row['message_id']
         topic_name = row[DB_TOPIC_NAME]

zerver/views/streams.py

@@ -476,7 +476,7 @@ def add_subscriptions_backend(
 
     # We can assume unique emails here for now, but we should eventually
     # convert this function to be more id-centric.
-    email_to_user_profile: Dict[str, UserProfile] = dict()
+    email_to_user_profile: Dict[str, UserProfile] = {}
 
     result: Dict[str, Any] = dict(subscribed=defaultdict(list), already_subscribed=defaultdict(list))
     for (subscriber, stream) in subscribed:

zerver/webhooks/bitbucket3/view.py

@@ -51,7 +51,7 @@ PULL_REQUEST_OPENED_OR_MODIFIED_TEMPLATE_WITH_REVIEWERS_WITH_TITLE = """
 def fixture_to_headers(fixture_name: str) -> Dict[str, str]:
     if fixture_name == "diagnostics_ping":
         return {"HTTP_X_EVENT_KEY": "diagnostics:ping"}
-    return dict()
+    return {}
 
 def get_user_name(payload: Dict[str, Any]) -> str:
     user_name = "[{name}]({url})".format(name=payload["actor"]["name"],

zilencer/management/commands/populate_db.py

@@ -715,7 +715,7 @@ def generate_and_send_messages(data: Tuple[int, Sequence[Sequence[int]], Mapping
                              Subscription.objects.filter(recipient_id=h)]
 
     # Generate different topics for each stream
-    possible_topics = dict()
+    possible_topics = {}
     for stream_id in recipient_streams:
         possible_topics[stream_id] = generate_topics(options["max_topics"])