Refs #23968 -- Removed unnecessary lists, generators, and tuple calls.

Author: jdufresne

django/apps/registry.py

@@ -300,7 +300,7 @@ def set_available_apps(self, available):
         This method is safe in the sense that it doesn't trigger any imports.
         """
         available = set(available)
-        installed = set(app_config.name for app_config in self.get_app_configs())
+        installed = {app_config.name for app_config in self.get_app_configs()}
         if not available.issubset(installed):
             raise ValueError(
                 "Available apps isn't a subset of installed apps, extra apps: %s"

django/contrib/admin/templatetags/admin_urls.py

@@ -25,7 +25,7 @@ def add_preserved_filters(context, url, popup=False, to_field=None):
 
     parsed_url = list(urlparse(url))
     parsed_qs = dict(parse_qsl(parsed_url[4]))
-    merged_qs = dict()
+    merged_qs = {}
 
     if opts and preserved_filters:
         preserved_filters = dict(parse_qsl(preserved_filters))

django/contrib/auth/backends.py

@@ -54,7 +54,7 @@ def _get_permissions(self, user_obj, obj, from_name):
             else:
                 perms = getattr(self, '_get_%s_permissions' % from_name)(user_obj)
             perms = perms.values_list('content_type__app_label', 'codename').order_by()
-            setattr(user_obj, perm_cache_name, set("%s.%s" % (ct, name) for ct, name in perms))
+            setattr(user_obj, perm_cache_name, {"%s.%s" % (ct, name) for ct, name in perms})
         return getattr(user_obj, perm_cache_name)
 
     def get_user_permissions(self, user_obj, obj=None):

django/contrib/auth/management/__init__.py

@@ -50,7 +50,7 @@ def create_permissions(app_config, verbosity=2, interactive=True, using=DEFAULT_
 
     # This will hold the permissions we're looking for as
     # (content_type, (codename, name))
-    searched_perms = list()
+    searched_perms = []
     # The codenames and ctypes that should exist.
     ctypes = set()
     for klass in app_config.get_models():

django/contrib/contenttypes/fields.py

@@ -529,7 +529,7 @@ def get_prefetch_queryset(self, instances, queryset=None):
 
             query = {
                 '%s__pk' % self.content_type_field_name: self.content_type.id,
-                '%s__in' % self.object_id_field_name: set(obj._get_pk_val() for obj in instances)
+                '%s__in' % self.object_id_field_name: {obj._get_pk_val() for obj in instances}
             }
 
             # We (possibly) need to convert object IDs to the type of the

django/contrib/flatpages/templatetags/flatpages.py

@@ -72,7 +72,7 @@ def get_flatpages(parser, token):
     bits = token.split_contents()
     syntax_message = ("%(tag_name)s expects a syntax of %(tag_name)s "
                       "['url_starts_with'] [for user] as context_name" %
-                      dict(tag_name=bits[0]))
+                      {'tag_name': bits[0]})
     # Must have at 3-6 bits in the tag
     if len(bits) >= 3 and len(bits) <= 6:
 

django/core/cache/backends/memcached.py

@@ -159,7 +159,7 @@ def __init__(self, server, params):
     @property
     def _cache(self):
         if getattr(self, '_client', None) is None:
-            client_kwargs = dict(pickleProtocol=pickle.HIGHEST_PROTOCOL)
+            client_kwargs = {'pickleProtocol': pickle.HIGHEST_PROTOCOL}
             client_kwargs.update(self._options)
             self._client = self._lib.Client(self._servers, **client_kwargs)
         return self._client

django/core/management/base.py

@@ -428,7 +428,7 @@ def check_migrations(self):
 
         plan = executor.migration_plan(executor.loader.graph.leaf_nodes())
         if plan:
-            apps_waiting_migration = sorted(set(migration.app_label for migration, backwards in plan))
+            apps_waiting_migration = sorted({migration.app_label for migration, backwards in plan})
             self.stdout.write(
                 self.style.NOTICE(
                     "\nYou have %(unpplied_migration_count)s unapplied migration(s). "

django/core/management/commands/loaddata.py

@@ -235,7 +235,7 @@ def find_fixtures(self, fixture_label):
             '.'.join(ext for ext in combo if ext)
             for combo in product(databases, ser_fmts, cmp_fmts)
         )
-        targets = set('.'.join((fixture_name, suffix)) for suffix in suffixes)
+        targets = {'.'.join((fixture_name, suffix)) for suffix in suffixes}
 
         fixture_files = []
         for fixture_dir in fixture_dirs:

django/core/management/commands/makemigrations.py

@@ -78,7 +78,7 @@ def handle(self, *app_labels, **options):
         loader = MigrationLoader(None, ignore_no_migrations=True)
 
         # Raise an error if any migrations are applied before their dependencies.
-        consistency_check_labels = set(config.label for config in apps.get_app_configs())
+        consistency_check_labels = {config.label for config in apps.get_app_configs()}
         # Non-default databases are only checked if database routers used.
         aliases_to_check = connections if settings.DATABASE_ROUTERS else [DEFAULT_DB_ALIAS]
         for alias in sorted(aliases_to_check):

django/core/management/commands/migrate.py

@@ -143,7 +143,7 @@ def handle(self, *args, **options):
             if target_app_labels_only:
                 self.stdout.write(
                     self.style.MIGRATE_LABEL("  Apply all migrations: ") +
-                    (", ".join(sorted(set(a for a, n in targets))) or "(none)")
+                    (", ".join(sorted({a for a, n in targets})) or "(none)")
                 )
             else:
                 if targets[0][1] is None:

django/db/backends/base/schema.py

@@ -324,8 +324,8 @@ def alter_unique_together(self, model, old_unique_together, new_unique_together)
         unique_togethers must be doubly-nested, not the single-nested
         ["foo", "bar"] format.
         """
-        olds = set(tuple(fields) for fields in old_unique_together)
-        news = set(tuple(fields) for fields in new_unique_together)
+        olds = {tuple(fields) for fields in old_unique_together}
+        news = {tuple(fields) for fields in new_unique_together}
         # Deleted uniques
         for fields in olds.difference(news):
             self._delete_composed_index(model, fields, {'unique': True}, self.sql_delete_unique)
@@ -340,8 +340,8 @@ def alter_index_together(self, model, old_index_together, new_index_together):
         index_togethers must be doubly-nested, not the single-nested
         ["foo", "bar"] format.
         """
-        olds = set(tuple(fields) for fields in old_index_together)
-        news = set(tuple(fields) for fields in new_index_together)
+        olds = {tuple(fields) for fields in old_index_together}
+        news = {tuple(fields) for fields in new_index_together}
         # Deleted indexes
         for fields in olds.difference(news):
             self._delete_composed_index(model, fields, {'index': True}, self.sql_delete_index)

django/db/backends/sqlite3/schema.py

@@ -169,7 +169,7 @@ def is_self_referential(f):
             'indexes': indexes,
             'apps': apps,
         }
-        meta = type("Meta", tuple(), meta_contents)
+        meta = type("Meta", (), meta_contents)
         body['Meta'] = meta
         body['__module__'] = model.__module__
 

django/db/migrations/autodetector.py

@@ -1065,14 +1065,14 @@ def generate_altered_options(self):
             old_model_name = self.renamed_models.get((app_label, model_name), model_name)
             old_model_state = self.from_state.models[app_label, old_model_name]
             new_model_state = self.to_state.models[app_label, model_name]
-            old_options = dict(
-                option for option in old_model_state.options.items()
-                if option[0] in AlterModelOptions.ALTER_OPTION_KEYS
-            )
-            new_options = dict(
-                option for option in new_model_state.options.items()
-                if option[0] in AlterModelOptions.ALTER_OPTION_KEYS
-            )
+            old_options = {
+                key: value for key, value in old_model_state.options.items()
+                if key in AlterModelOptions.ALTER_OPTION_KEYS
+            }
+            new_options = {
+                key: value for key, value in new_model_state.options.items()
+                if key in AlterModelOptions.ALTER_OPTION_KEYS
+            }
             if old_options != new_options:
                 self.add_operation(
                     app_label,

django/db/migrations/operations/models.py

@@ -496,7 +496,7 @@ class AlterUniqueTogether(FieldRelatedOptionOperation):
 
     def __init__(self, name, unique_together):
         unique_together = normalize_together(unique_together)
-        self.unique_together = set(tuple(cons) for cons in unique_together)
+        self.unique_together = {tuple(cons) for cons in unique_together}
         super().__init__(name)
 
     def deconstruct(self):
@@ -550,7 +550,7 @@ class AlterIndexTogether(FieldRelatedOptionOperation):
 
     def __init__(self, name, index_together):
         index_together = normalize_together(index_together)
-        self.index_together = set(tuple(cons) for cons in index_together)
+        self.index_together = {tuple(cons) for cons in index_together}
         super().__init__(name)
 
     def deconstruct(self):

django/db/migrations/recorder.py

@@ -55,7 +55,7 @@ def ensure_schema(self):
     def applied_migrations(self):
         """Return a set of (app, name) of applied migrations."""
         self.ensure_schema()
-        return set(tuple(x) for x in self.migration_qs.values_list("app", "name"))
+        return {tuple(x) for x in self.migration_qs.values_list("app", "name")}
 
     def record_applied(self, app, name):
         """Record that a migration was applied."""

django/db/migrations/state.py

@@ -559,7 +559,7 @@ def render(self, apps):
         # First, make a Meta object
         meta_contents = {'app_label': self.app_label, "apps": apps}
         meta_contents.update(self.options)
-        meta = type("Meta", tuple(), meta_contents)
+        meta = type("Meta", (), meta_contents)
         # Then, work out our bases
         try:
             bases = tuple(

django/db/models/base.py

@@ -1294,7 +1294,7 @@ def _check_m2m_through_same_relationship(cls):
     @classmethod
     def _check_id_field(cls):
         """Check if `id` field is a primary key."""
-        fields = list(f for f in cls._meta.local_fields if f.name == 'id' and f != cls._meta.pk)
+        fields = [f for f in cls._meta.local_fields if f.name == 'id' and f != cls._meta.pk]
         # fields is empty or consists of the invalid "id" field
         if fields and not fields[0].primary_key and cls._meta.pk.name == 'id':
             return [

django/db/models/fields/related_descriptors.py

@@ -122,7 +122,7 @@ def get_prefetch_queryset(self, instances, queryset=None):
         # The check for len(...) == 1 is a special case that allows the query
         # to be join-less and smaller. Refs #21760.
         if self.field.remote_field.is_hidden() or len(self.field.foreign_related_fields) == 1:
-            query = {'%s__in' % related_field.name: set(instance_attr(inst)[0] for inst in instances)}
+            query = {'%s__in' % related_field.name: {instance_attr(inst)[0] for inst in instances}}
         else:
             query = {'%s__in' % self.field.related_query_name(): instances}
         queryset = queryset.filter(**query)

django/db/models/options.py

@@ -20,7 +20,7 @@
 
 PROXY_PARENTS = object()
 
-EMPTY_RELATION_TREE = tuple()
+EMPTY_RELATION_TREE = ()
 
 IMMUTABLE_WARNING = (
     "The return type of '%s' should never be mutated. If you want to manipulate this list "

django/db/models/sql/query.py

@@ -1251,8 +1251,7 @@ def add_q(self, q_object):
         # (Consider case where rel_a is LOUTER and rel_a__col=1 is added - if
         # rel_a doesn't produce any rows, then the whole condition must fail.
         # So, demotion is OK.
-        existing_inner = set(
-            (a for a in self.alias_map if self.alias_map[a].join_type == INNER))
+        existing_inner = {a for a in self.alias_map if self.alias_map[a].join_type == INNER}
         clause, _ = self._add_q(q_object, self.used_aliases)
         if clause:
             self.where.add(clause, AND)
@@ -1437,8 +1436,8 @@ def trim_joins(self, targets, joins, path):
         for pos, info in enumerate(reversed(path)):
             if len(joins) == 1 or not info.direct:
                 break
-            join_targets = set(t.column for t in info.join_field.foreign_related_fields)
-            cur_targets = set(t.column for t in targets)
+            join_targets = {t.column for t in info.join_field.foreign_related_fields}
+            cur_targets = {t.column for t in targets}
             if not cur_targets.issubset(join_targets):
                 break
             targets_dict = {r[1].column: r[0] for r in info.join_field.related_fields if r[1].column in cur_targets}

django/forms/boundfield.py

@@ -47,10 +47,10 @@ def subwidgets(self):
         id_ = self.field.widget.attrs.get('id') or self.auto_id
         attrs = {'id': id_} if id_ else {}
         attrs = self.build_widget_attrs(attrs)
-        return list(
+        return [
             BoundWidget(self.field.widget, widget, self.form.renderer)
             for widget in self.field.widget.subwidgets(self.html_name, self.value(), attrs=attrs)
-        )
+        ]
 
     def __bool__(self):
         # BoundField evaluates to True even if it doesn't have subwidgets.

django/forms/fields.py

@@ -873,8 +873,8 @@ def has_changed(self, initial, data):
             data = []
         if len(initial) != len(data):
             return True
-        initial_set = set(str(value) for value in initial)
-        data_set = set(str(value) for value in data)
+        initial_set = {str(value) for value in initial}
+        data_set = {str(value) for value in data}
         return data_set != initial_set
 
 

django/forms/models.py

@@ -1289,7 +1289,7 @@ def _check_values(self, value):
                     params={'pk': pk},
                 )
         qs = self.queryset.filter(**{'%s__in' % key: value})
-        pks = set(str(getattr(o, key)) for o in qs)
+        pks = {str(getattr(o, key)) for o in qs}
         for val in value:
             if str(val) not in pks:
                 raise ValidationError(
@@ -1313,8 +1313,8 @@ def has_changed(self, initial, data):
             data = []
         if len(initial) != len(data):
             return True
-        initial_set = set(str(value) for value in self.prepare_value(initial))
-        data_set = set(str(value) for value in data)
+        initial_set = {str(value) for value in self.prepare_value(initial)}
+        data_set = {str(value) for value in data}
         return data_set != initial_set
 
 

django/utils/cache.py

@@ -287,7 +287,7 @@ def patch_vary_headers(response, newheaders):
     else:
         vary_headers = []
     # Use .lower() here so we treat headers as case-insensitive.
-    existing_headers = set(header.lower() for header in vary_headers)
+    existing_headers = {header.lower() for header in vary_headers}
     additional_headers = [newheader for newheader in newheaders
                           if newheader.lower() not in existing_headers]
     response['Vary'] = ', '.join(vary_headers + additional_headers)
@@ -300,7 +300,7 @@ def has_vary_header(response, header_query):
     if not response.has_header('Vary'):
         return False
     vary_headers = cc_delim_re.split(response['Vary'])
-    existing_headers = set(header.lower() for header in vary_headers)
+    existing_headers = {header.lower() for header in vary_headers}
     return header_query.lower() in existing_headers
 
 

django/views/i18n.py

@@ -230,7 +230,7 @@ def get(self, request, *args, **kwargs):
         return self.render_to_response(context)
 
     def get_paths(self, packages):
-        allowable_packages = dict((app_config.name, app_config) for app_config in apps.get_app_configs())
+        allowable_packages = {app_config.name: app_config for app_config in apps.get_app_configs()}
         app_configs = [allowable_packages[p] for p in packages if p in allowable_packages]
         # paths of requested packages
         return [os.path.join(app.path, 'locale') for app in app_configs]

docs/_ext/djangodocs.py

@@ -250,8 +250,7 @@ def visit_desc_parameterlist(self, node):
         self.first_param = 1
         self.optional_param_level = 0
         self.param_separator = node.child_text_separator
-        self.required_params_left = sum([isinstance(c, addnodes.desc_parameter)
-                                         for c in node.children])
+        self.required_params_left = sum(isinstance(c, addnodes.desc_parameter) for c in node.children)
 
     def depart_desc_parameterlist(self, node):
         self.body.append(')')

scripts/manage_translations.py

@@ -114,7 +114,7 @@ def lang_stats(resources=None, languages=None):
 
     for name, dir_ in locale_dirs:
         print("\nShowing translations stats for '%s':" % name)
-        langs = sorted([d for d in os.listdir(dir_) if not d.startswith('_')])
+        langs = sorted(d for d in os.listdir(dir_) if not d.startswith('_'))
         for lang in langs:
             if languages and lang not in languages:
                 continue
@@ -142,7 +142,7 @@ def fetch(resources=None, languages=None):
         # Transifex pull
         if languages is None:
             call('tx pull -r %(res)s -a -f  --minimum-perc=5' % {'res': _tx_resource_for_name(name)}, shell=True)
-            target_langs = sorted([d for d in os.listdir(dir_) if not d.startswith('_') and d != 'en'])
+            target_langs = sorted(d for d in os.listdir(dir_) if not d.startswith('_') and d != 'en')
         else:
             for lang in languages:
                 call('tx pull -r %(res)s -f -l %(lang)s' % {

tests/admin_views/urls.py

@@ -8,7 +8,7 @@
     url(r'^test_admin/admin/secure-view2/$', views.secure_view2, name='secure_view2'),
     url(r'^test_admin/admin/', admin.site.urls),
     url(r'^test_admin/admin2/', customadmin.site.urls),
-    url(r'^test_admin/admin3/', (admin.site.get_urls(), 'admin', 'admin3'), dict(form_url='pony')),
+    url(r'^test_admin/admin3/', (admin.site.get_urls(), 'admin', 'admin3'), {'form_url': 'pony'}),
     url(r'^test_admin/admin4/', customadmin.simple_site.urls),
     url(r'^test_admin/admin5/', admin.site2.urls),
     url(r'^test_admin/admin7/', admin.site7.urls),

tests/admin_widgets/tests.py

@@ -564,14 +564,14 @@ def test_render(self):
             w.render('test', [m1.pk, m2.pk], attrs={}), (
                 '<input type="text" name="test" value="%(m1pk)s,%(m2pk)s" class="vManyToManyRawIdAdminField" />'
                 '<a href="/admin_widgets/member/" class="related-lookup" id="lookup_id_test" title="Lookup"></a>'
-            ) % dict(m1pk=m1.pk, m2pk=m2.pk)
+            ) % {'m1pk': m1.pk, 'm2pk': m2.pk}
         )
 
         self.assertHTMLEqual(
             w.render('test', [m1.pk]), (
                 '<input type="text" name="test" value="%(m1pk)s" class="vManyToManyRawIdAdminField">'
                 '<a href="/admin_widgets/member/" class="related-lookup" id="lookup_id_test" title="Lookup"></a>'
-            ) % dict(m1pk=m1.pk)
+            ) % {'m1pk': m1.pk}
         )
 
     def test_m2m_related_model_not_in_admin(self):

tests/aggregation/tests.py

@@ -1114,7 +1114,7 @@ class MySum(Sum):
         # test completely changing how the output is rendered
         def lower_case_function_override(self, compiler, connection):
             sql, params = compiler.compile(self.source_expressions[0])
-            substitutions = dict(function=self.function.lower(), expressions=sql)
+            substitutions = {'function': self.function.lower(), 'expressions': sql}
             substitutions.update(self.extra)
             return self.template % substitutions, params
         setattr(MySum, 'as_' + connection.vendor, lower_case_function_override)
@@ -1141,7 +1141,7 @@ def lower_case_function_super(self, compiler, connection):
 
         # test overriding all parts of the template
         def be_evil(self, compiler, connection):
-            substitutions = dict(function='MAX', expressions='2')
+            substitutions = {'function': 'MAX', 'expressions': '2'}
             substitutions.update(self.extra)
             return self.template % substitutions, ()
         setattr(MySum, 'as_' + connection.vendor, be_evil)

tests/annotations/tests.py

@@ -197,7 +197,7 @@ def test_distinct_on_with_annotation(self):
             name_lower=Lower('last_name'),
         ).distinct('name_lower')
 
-        self.assertEqual(set(p.last_name for p in people), {'Stark', 'Roosevelt'})
+        self.assertEqual({p.last_name for p in people}, {'Stark', 'Roosevelt'})
         self.assertEqual(len(people), 2)
 
         people2 = Employee.objects.annotate(