Fixed #28982 -- Simplified code with and/or.

django/contrib/admin/sites.py

@@ -94,9 +94,7 @@ class AdminSite:
 
         If a model is abstract, raise ImproperlyConfigured.
         """
-        if not admin_class:
+        admin_class = admin_class or ModelAdmin
-            admin_class = ModelAdmin
-
         if isinstance(model_or_iterable, ModelBase):
             model_or_iterable = [model_or_iterable]
         for model in model_or_iterable:

django/contrib/admin/views/main.py

@@ -86,8 +86,7 @@ class ChangeList:
         """
         Return all params except IGNORED_PARAMS.
         """
-        if not params:
+        params = params or self.params
-            params = self.params
         lookup_params = params.copy()  # a dictionary of the query string
         # Remove all the parameters that are globally and systematically
         # ignored.

django/contrib/admindocs/utils.py

@@ -71,8 +71,7 @@ def parse_rst(text, default_reference_context, thing_being_parsed=None):
         'raw_enabled': False,
         'file_insertion_enabled': False,
     }
-    if thing_being_parsed:
+    thing_being_parsed = thing_being_parsed and force_bytes('<%s>' % thing_being_parsed)
-        thing_being_parsed = force_bytes("<%s>" % thing_being_parsed)
     # Wrap ``text`` in some reST that sets the default role to ``cmsreference``,
     # then restores it.
     source = """

django/contrib/admindocs/views.py

@@ -75,10 +75,8 @@ class TemplateTagIndexView(BaseAdminDocsView):
             for module_name, library in builtin_libs + app_libs:
                 for tag_name, tag_func in library.tags.items():
                     title, body, metadata = utils.parse_docstring(tag_func.__doc__)
-                    if title:
+                    title = title and utils.parse_rst(title, 'tag', _('tag:') + tag_name)
-                        title = utils.parse_rst(title, 'tag', _('tag:') + tag_name)
+                    body = body and utils.parse_rst(body, 'tag', _('tag:') + tag_name)
-                    if body:
-                        body = utils.parse_rst(body, 'tag', _('tag:') + tag_name)
                     for key in metadata:
                         metadata[key] = utils.parse_rst(metadata[key], 'tag', _('tag:') + tag_name)
                     tag_library = module_name.split('.')[-1]
@@ -108,10 +106,8 @@ class TemplateFilterIndexView(BaseAdminDocsView):
             for module_name, library in builtin_libs + app_libs:
                 for filter_name, filter_func in library.filters.items():
                     title, body, metadata = utils.parse_docstring(filter_func.__doc__)
-                    if title:
+                    title = title and utils.parse_rst(title, 'filter', _('filter:') + filter_name)
-                        title = utils.parse_rst(title, 'filter', _('filter:') + filter_name)
+                    body = body and utils.parse_rst(body, 'filter', _('filter:') + filter_name)
-                    if body:
-                        body = utils.parse_rst(body, 'filter', _('filter:') + filter_name)
                     for key in metadata:
                         metadata[key] = utils.parse_rst(metadata[key], 'filter', _('filter:') + filter_name)
                     tag_library = module_name.split('.')[-1]
@@ -174,10 +170,8 @@ class ViewDetailView(BaseAdminDocsView):
         if view_func is None:
             raise Http404
         title, body, metadata = utils.parse_docstring(view_func.__doc__)
-        if title:
+        title = title and utils.parse_rst(title, 'view', _('view:') + view)
-            title = utils.parse_rst(title, 'view', _('view:') + view)
+        body = body and utils.parse_rst(body, 'view', _('view:') + view)
-        if body:
-            body = utils.parse_rst(body, 'view', _('view:') + view)
         for key in metadata:
             metadata[key] = utils.parse_rst(metadata[key], 'model', _('view:') + view)
         return super().get_context_data(**{
@@ -215,10 +209,8 @@ class ModelDetailView(BaseAdminDocsView):
         opts = model._meta
 
         title, body, metadata = utils.parse_docstring(model.__doc__)
-        if title:
+        title = title and utils.parse_rst(title, 'model', _('model:') + model_name)
-            title = utils.parse_rst(title, 'model', _('model:') + model_name)
+        body = body and utils.parse_rst(body, 'model', _('model:') + model_name)
-        if body:
-            body = utils.parse_rst(body, 'model', _('model:') + model_name)
 
         # Gather fields/field descriptions.
         fields = []
@@ -275,8 +267,9 @@ class ModelDetailView(BaseAdminDocsView):
                 except StopIteration:
                     continue
                 verbose = func.__doc__
-                if verbose:
+                verbose = verbose and (
-                    verbose = utils.parse_rst(utils.trim_docstring(verbose), 'model', _('model:') + opts.model_name)
+                    utils.parse_rst(utils.trim_docstring(verbose), 'model', _('model:') + opts.model_name)
+                )
                 # If a method has no arguments, show it as a 'field', otherwise
                 # as a 'method with arguments'.
                 if func_has_no_args(func) and not func_accepts_kwargs(func) and not func_accepts_var_args(func):

django/contrib/auth/admin.py

@@ -88,10 +88,8 @@ class UserAdmin(admin.ModelAdmin):
         ] + super().get_urls()
 
     def lookup_allowed(self, lookup, value):
-        # See #20078: we don't want to allow any lookups involving passwords.
+        # Don't allow lookups involving passwords.
-        if lookup.startswith('password'):
+        return not lookup.startswith('password') and super().lookup_allowed(lookup, value)
-            return False
-        return super().lookup_allowed(lookup, value)
 
     @sensitive_post_parameters_m
     @csrf_protect_m

django/contrib/auth/backends.py

@@ -82,9 +82,7 @@ class ModelBackend:
         return user_obj._perm_cache
 
     def has_perm(self, user_obj, perm, obj=None):
-        if not user_obj.is_active:
+        return user_obj.is_active and perm in self.get_all_permissions(user_obj, obj)
-            return False
-        return perm in self.get_all_permissions(user_obj, obj)
 
     def has_module_perms(self, user_obj, app_label):
         """

django/contrib/auth/hashers.py

@@ -73,10 +73,7 @@ def make_password(password, salt=None, hasher='default'):
     if password is None:
         return UNUSABLE_PASSWORD_PREFIX + get_random_string(UNUSABLE_PASSWORD_SUFFIX_LENGTH)
     hasher = get_hasher(hasher)
-
+    salt = salt or hasher.salt()
-    if not salt:
-        salt = hasher.salt()
-
     return hasher.encode(password, salt)
 
 
@@ -244,8 +241,7 @@ class PBKDF2PasswordHasher(BasePasswordHasher):
     def encode(self, password, salt, iterations=None):
         assert password is not None
         assert salt and '$' not in salt
-        if not iterations:
+        iterations = iterations or self.iterations
-            iterations = self.iterations
         hash = pbkdf2(password, salt, iterations, digest=self.digest)
         hash = base64.b64encode(hash).decode('ascii').strip()
         return "%s$%d$%s$%s" % (self.algorithm, iterations, salt, hash)

django/contrib/auth/views.py

@@ -164,9 +164,7 @@ def logout_then_login(request, login_url=None):
     """
     Log out the user if they are logged in. Then redirect to the login page.
     """
-    if not login_url:
+    login_url = resolve_url(login_url or settings.LOGIN_URL)
-        login_url = settings.LOGIN_URL
-    login_url = resolve_url(login_url)
     return LogoutView.as_view(next_page=login_url)(request)
 
 

django/contrib/gis/gdal/raster/band.py

@@ -186,15 +186,9 @@ class GDALBand(GDALRasterBase):
 
         Allowed input data types are bytes, memoryview, list, tuple, and array.
         """
-        if not offset:
+        offset = offset or (0, 0)
-            offset = (0, 0)
+        size = size or (self.width - offset[0], self.height - offset[1])
-
+        shape = shape or size
-        if not size:
-            size = (self.width - offset[0], self.height - offset[1])
-
-        if not shape:
-            shape = size
-
         if any(x <= 0 for x in size):
             raise ValueError('Offset too big for this raster.')
 

django/contrib/gis/geoip2/base.py

@@ -73,10 +73,9 @@ class GeoIP2:
             raise GeoIP2Exception('Invalid GeoIP caching option: %s' % cache)
 
         # Getting the GeoIP data path.
+        path = path or GEOIP_SETTINGS['GEOIP_PATH']
         if not path:
-            path = GEOIP_SETTINGS['GEOIP_PATH']
+            raise GeoIP2Exception('GeoIP path must be provided via parameter or the GEOIP_PATH setting.')
-            if not path:
-                raise GeoIP2Exception('GeoIP path must be provided via parameter or the GEOIP_PATH setting.')
         if not isinstance(path, str):
             raise TypeError('Invalid path type: %s' % type(path).__name__)
 
@@ -115,10 +114,7 @@ class GeoIP2:
 
     @property
     def _reader(self):
-        if self._country:
+        return self._country or self._city
-            return self._country
-        else:
-            return self._city
 
     @property
     def _country_or_city(self):

django/contrib/gis/geos/prototypes/io.py

@@ -300,8 +300,7 @@ thread_context = ThreadLocalIO()
 # These module-level routines return the I/O object that is local to the
 # thread. If the I/O object does not exist yet it will be initialized.
 def wkt_r():
-    if not thread_context.wkt_r:
+    thread_context.wkt_r = thread_context.wkt_r or _WKTReader()
-        thread_context.wkt_r = _WKTReader()
     return thread_context.wkt_r
 
 
@@ -316,8 +315,7 @@ def wkt_w(dim=2, trim=False, precision=None):
 
 
 def wkb_r():
-    if not thread_context.wkb_r:
+    thread_context.wkb_r = thread_context.wkb_r or _WKBReader()
-        thread_context.wkb_r = _WKBReader()
     return thread_context.wkb_r
 
 

django/contrib/gis/geos/prototypes/threadsafe.py

@@ -41,8 +41,7 @@ class GEOSFunc:
 
     def __call__(self, *args):
         # Create a context handle if one doesn't exist for this thread.
-        if not self.thread_context.handle:
+        self.thread_context.handle = self.thread_context.handle or GEOSContextHandle()
-            self.thread_context.handle = GEOSContextHandle()
         # Call the threaded GEOS routine with the pointer of the context handle
         # as the first argument.
         return self.cfunc(self.thread_context.handle.ptr, *args)

django/contrib/gis/utils/srs.py

@@ -32,8 +32,7 @@ def add_srs_entry(srs, auth_name='EPSG', auth_srid=None, ref_sys_name=None,
       of `django.db.DEFAULT_DB_ALIAS` (at the time of this writing, its value
       is 'default').
     """
-    if not database:
+    database = database or DEFAULT_DB_ALIAS
-        database = DEFAULT_DB_ALIAS
     connection = connections[database]
 
     if not hasattr(connection.ops, 'spatial_version'):

django/contrib/sessions/backends/base.py

@@ -240,8 +240,7 @@ class SessionBase:
 
         if isinstance(expiry, datetime):
             return expiry
-        if not expiry:   # Checks both None and 0 cases
+        expiry = expiry or settings.SESSION_COOKIE_AGE   # Checks both None and 0 cases
-            expiry = settings.SESSION_COOKIE_AGE
         return modification + timedelta(seconds=expiry)
 
     def set_expiry(self, value):

django/contrib/sessions/backends/cached_db.py

@@ -41,9 +41,7 @@ class SessionStore(DBStore):
         return data
 
     def exists(self, session_key):
-        if session_key and (self.cache_key_prefix + session_key) in self._cache:
+        return session_key and (self.cache_key_prefix + session_key) in self._cache or super().exists(session_key)
-            return True
-        return super().exists(session_key)
 
     def save(self, must_create=False):
         super().save(must_create)

django/contrib/sessions/backends/file.py

@@ -27,10 +27,7 @@ class SessionStore(SessionBase):
         try:
             return cls._storage_path
         except AttributeError:
-            storage_path = getattr(settings, "SESSION_FILE_PATH", None)
+            storage_path = getattr(settings, 'SESSION_FILE_PATH', None) or tempfile.gettempdir()
-            if not storage_path:
-                storage_path = tempfile.gettempdir()
-
             # Make sure the storage path is valid.
             if not os.path.isdir(storage_path):
                 raise ImproperlyConfigured(

django/contrib/staticfiles/storage.py

@@ -85,9 +85,7 @@ class HashedFilesMixin:
         # `name` is the base name to construct the new hashed filename from.
         parsed_name = urlsplit(unquote(name))
         clean_name = parsed_name.path.strip()
-        if filename:
+        filename = (filename and urlsplit(unquote(filename)).path.strip()) or clean_name
-            filename = urlsplit(unquote(filename)).path.strip()
-        filename = filename or clean_name
         opened = False
         if content is None:
             if not self.exists(filename):

django/core/cache/backends/locmem.py

@@ -98,9 +98,7 @@ class LocMemCache(BaseCache):
 
     def _has_expired(self, key):
         exp = self._expire_info.get(key, -1)
-        if exp is None or exp > time.time():
+        return exp is not None and exp <= time.time()
-            return False
-        return True
 
     def _cull(self):
         if self._cull_frequency == 0:

django/core/files/base.py

@@ -59,9 +59,7 @@ class File(FileProxyMixin):
         Read the file and yield chunks of ``chunk_size`` bytes (defaults to
         ``UploadedFile.DEFAULT_CHUNK_SIZE``).
         """
-        if not chunk_size:
+        chunk_size = chunk_size or self.DEFAULT_CHUNK_SIZE
-            chunk_size = self.DEFAULT_CHUNK_SIZE
-
         try:
             self.seek(0)
         except (AttributeError, UnsupportedOperation):
@@ -81,9 +79,7 @@ class File(FileProxyMixin):
         always return ``False`` -- there's no good reason to read from memory in
         chunks.
         """
-        if not chunk_size:
+        return self.size > (chunk_size or self.DEFAULT_CHUNK_SIZE)
-            chunk_size = self.DEFAULT_CHUNK_SIZE
-        return self.size > chunk_size
 
     def __iter__(self):
         # Iterate over this file-like object by newlines

django/core/handlers/wsgi.py

@@ -176,9 +176,7 @@ def get_script_name(environ):
     # rewrites. Unfortunately not every Web server (lighttpd!) passes this
     # information through all the time, so FORCE_SCRIPT_NAME, above, is still
     # needed.
-    script_url = get_bytes_from_wsgi(environ, 'SCRIPT_URL', '')
+    script_url = get_bytes_from_wsgi(environ, 'SCRIPT_URL', '') or get_bytes_from_wsgi(environ, 'REDIRECT_URL', '')
-    if not script_url:
-        script_url = get_bytes_from_wsgi(environ, 'REDIRECT_URL', '')
 
     if script_url:
         if b'//' in script_url:

django/core/mail/message.py

@@ -309,11 +309,7 @@ class EmailMessage:
             self.attachments.append(filename)
         else:
             assert content is not None
-
+            mimetype = mimetype or mimetypes.guess_type(filename)[0] or DEFAULT_ATTACHMENT_MIME_TYPE
-            if not mimetype:
-                mimetype, _ = mimetypes.guess_type(filename)
-                if not mimetype:
-                    mimetype = DEFAULT_ATTACHMENT_MIME_TYPE
             basetype, subtype = mimetype.split('/', 1)
 
             if basetype == 'text':

django/core/management/color.py

@@ -19,9 +19,7 @@ def supports_color():
 
     # isatty is not always implemented, #6223.
     is_a_tty = hasattr(sys.stdout, 'isatty') and sys.stdout.isatty()
-    if not supported_platform or not is_a_tty:
+    return supported_platform and is_a_tty
-        return False
-    return True
 
 
 class Style:

django/core/management/commands/makemessages.py

@@ -502,8 +502,7 @@ class Command(BaseCommand):
                         if os.path.abspath(dirpath).startswith(os.path.dirname(path)):
                             locale_dir = path
                             break
-                    if not locale_dir:
+                    locale_dir = locale_dir or self.default_locale_path or NO_LOCALE_DIR
-                        locale_dir = self.default_locale_path or NO_LOCALE_DIR
                     all_files.append(self.translatable_file_class(dirpath, filename, locale_dir))
         return sorted(all_files)
 

django/core/serializers/base.py

@@ -96,8 +96,7 @@ class Serializer:
                         self.handle_m2m_field(obj, field)
             self.end_object(obj)
             progress_bar.update(count)
-            if self.first:
+            self.first = self.first and False
-                self.first = False
         self.end_serialization()
         return self.getvalue()
 

django/db/backends/mysql/schema.py

@@ -61,9 +61,7 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
                 field.get_internal_type() == 'ForeignKey' and
                 field.db_constraint):
             return False
-        if self._is_limited_data_type(field):
+        return not self._is_limited_data_type(field) and create_index
-            return False
-        return create_index
 
     def _delete_composed_index(self, model, fields, *args):
         """

django/db/backends/postgresql/creation.py

@@ -16,9 +16,7 @@ class DatabaseCreation(BaseDatabaseCreation):
             suffix += " ENCODING '{}'".format(encoding)
         if template:
             suffix += " TEMPLATE {}".format(self._quote_name(template))
-        if suffix:
+        return suffix and "WITH" + suffix
-            suffix = "WITH" + suffix
-        return suffix
 
     def sql_table_creation_suffix(self):
         test_settings = self.connection.settings_dict['TEST']

django/db/backends/postgresql/operations.py

@@ -131,11 +131,9 @@ class DatabaseOperations(BaseDatabaseOperations):
         sql = []
         for sequence_info in sequences:
             table_name = sequence_info['table']
-            column_name = sequence_info['column']
+            # 'id' will be the case if it's an m2m using an autogenerated
-            if not column_name:
+            # intermediate table (see BaseDatabaseIntrospection.sequence_list).
-                # This will be the case if it's an m2m using an autogenerated
+            column_name = sequence_info['column'] or 'id'
-                # intermediate table (see BaseDatabaseIntrospection.sequence_list)
-                column_name = 'id'
             sql.append("%s setval(pg_get_serial_sequence('%s','%s'), 1, false);" % (
                 style.SQL_KEYWORD('SELECT'),
                 style.SQL_TABLE(self.quote_name(table_name)),

django/db/models/aggregates.py

@@ -31,15 +31,13 @@ class Aggregate(Func):
         return source_expressions
 
     def set_source_expressions(self, exprs):
-        if self.filter:
+        self.filter = self.filter and exprs.pop()
-            self.filter = exprs.pop()
         return super().set_source_expressions(exprs)
 
     def resolve_expression(self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False):
         # Aggregates are not allowed in UPDATE queries, so ignore for_save
         c = super().resolve_expression(query, allow_joins, reuse, summarize)
-        if c.filter:
+        c.filter = c.filter and c.filter.resolve_expression(query, allow_joins, reuse, summarize)
-            c.filter = c.filter.resolve_expression(query, allow_joins, reuse, summarize)
         if not summarize:
             # Call Aggregate.get_source_expressions() to avoid
             # returning self.filter and including that in this loop.

django/db/models/base.py

@@ -549,8 +549,7 @@ class Model(metaclass=ModelBase):
         self.__dict__.update(state)
 
     def _get_pk_val(self, meta=None):
-        if not meta:
+        meta = meta or self._meta
-            meta = self._meta
         return getattr(self, meta.pk.attname)
 
     def _set_pk_val(self, value):
@@ -852,7 +851,8 @@ class Model(metaclass=ModelBase):
             # exists.
             return update_fields is not None or filtered.exists()
         if self._meta.select_on_save and not forced_update:
-            if filtered.exists():
+            return (
+                filtered.exists() and
                 # It may happen that the object is deleted from the DB right after
                 # this check, causing the subsequent UPDATE to return zero matching
                 # rows. The same result can occur in some rare cases when the
@@ -860,9 +860,8 @@ class Model(metaclass=ModelBase):
                 # successfully (a row is matched and updated). In order to
                 # distinguish these two cases, the object's existence in the
                 # database is again checked for if the UPDATE query returns 0.
-                return filtered._update(values) > 0 or filtered.exists()
+                (filtered._update(values) > 0 or filtered.exists())
-            else:
+            )
-                return False
         return filtered._update(values) > 0
 
     def _do_insert(self, manager, using, fields, update_pk, raw):

django/db/models/fields/__init__.py

@@ -694,8 +694,7 @@ class Field(RegisterLookupMixin):
         return self._db_tablespace or settings.DEFAULT_INDEX_TABLESPACE
 
     def set_attributes_from_name(self, name):
-        if not self.name:
+        self.name = self.name or name
-            self.name = name
         self.attname, self.column = self.get_attname_column()
         self.concrete = self.column is not None
         if self.verbose_name is None and self.name:

django/db/models/fields/files.py

@@ -314,9 +314,7 @@ class FileField(Field):
         if data is not None:
             # This value will be converted to str and stored in the
             # database, so leaving False as-is is not acceptable.
-            if not data:
+            setattr(instance, self.name, data or '')
-                data = ''
-            setattr(instance, self.name, data)
 
     def formfield(self, **kwargs):
         return super().formfield(**{

django/db/models/lookups.py

@@ -177,9 +177,7 @@ class FieldGetDbPrepValueMixin:
     def get_db_prep_lookup(self, value, connection):
         # For relational fields, use the output_field of the 'field' attribute.
         field = getattr(self.lhs.output_field, 'field', None)
-        get_db_prep_value = getattr(field, 'get_db_prep_value', None)
+        get_db_prep_value = getattr(field, 'get_db_prep_value', None) or self.lhs.output_field.get_db_prep_value
-        if not get_db_prep_value:
-            get_db_prep_value = self.lhs.output_field.get_db_prep_value
         return (
             '%s',
             [get_db_prep_value(v, connection, prepared=True) for v in value]

django/db/models/manager.py

@@ -107,8 +107,7 @@ class BaseManager:
         })
 
     def contribute_to_class(self, model, name):
-        if not self.name:
+        self.name = self.name or name
-            self.name = name
         self.model = model
 
         setattr(model, name, ManagerDescriptor(self))

django/db/models/sql/compiler.py

@@ -521,8 +521,7 @@ class SQLCompiler:
                 if grouping:
                     if distinct_fields:
                         raise NotImplementedError('annotate() + distinct(fields) is not implemented.')
-                    if not order_by:
+                    order_by = order_by or self.connection.ops.force_no_ordering()
-                        order_by = self.connection.ops.force_no_ordering()
                     result.append('GROUP BY %s' % ', '.join(grouping))
 
                 if having:
@@ -588,8 +587,7 @@ class SQLCompiler:
         if opts is None:
             opts = self.query.get_meta()
         only_load = self.deferred_to_columns()
-        if not start_alias:
+        start_alias = start_alias or self.query.get_initial_alias()
-            start_alias = self.query.get_initial_alias()
         # The 'seen_models' is used to optimize checking the needed parent
         # alias for a given field. This also includes None -> start_alias to
         # be used by local fields.
@@ -657,8 +655,7 @@ class SQLCompiler:
         # of the field is specified.
         if field.is_relation and opts.ordering and getattr(field, 'attname', None) != name:
             # Firstly, avoid infinite loops.
-            if not already_seen:
+            already_seen = already_seen or set()
-                already_seen = set()
             join_tuple = tuple(getattr(self.query.alias_map[j], 'join_cols', None) for j in joins)
             if join_tuple in already_seen:
                 raise FieldError('Infinite loop caused by ordering.')
@@ -680,8 +677,7 @@ class SQLCompiler:
         same input, as the prefixes of get_ordering() and get_distinct() must
         match. Executing SQL where this is not true is an error.
         """
-        if not alias:
+        alias = alias or self.query.get_initial_alias()
-            alias = self.query.get_initial_alias()
         field, targets, opts, joins, path = self.query.setup_joins(
             pieces, opts, alias)
         alias = joins[-1]
@@ -1037,8 +1033,7 @@ class SQLCompiler:
         is needed, as the filters describe an empty set. In that case, None is
         returned, to avoid any unnecessary database interaction.
         """
-        if not result_type:
+        result_type = result_type or NO_RESULTS
-            result_type = NO_RESULTS
         try:
             sql, params = self.as_sql()
             if not sql:

django/db/models/sql/query.py

@@ -805,9 +805,9 @@ class Query:
         if isinstance(self.group_by, tuple):
             self.group_by = tuple([col.relabeled_clone(change_map) for col in self.group_by])
         self.select = tuple([col.relabeled_clone(change_map) for col in self.select])
-        if self._annotations:
+        self._annotations = self._annotations and OrderedDict(
-            self._annotations = OrderedDict(
+            (key, col.relabeled_clone(change_map)) for key, col in self._annotations.items()
-                (key, col.relabeled_clone(change_map)) for key, col in self._annotations.items())
+        )
 
         # 2. Rename the alias in the internal table/alias datastructures.
         for old_alias, new_alias in change_map.items():
@@ -1061,9 +1061,7 @@ class Query:
         and get_transform().
         """
         # __exact is the default lookup if one isn't given.
-        if not lookups:
+        lookups = lookups or ['exact']
-            lookups = ['exact']
-
         for name in lookups[:-1]:
             lhs = self.try_transform(lhs, name)
         # First try get_lookup() so that the lookup takes precedence if the lhs
@@ -2050,10 +2048,10 @@ class Query:
         # used. The proper fix would be to defer all decisions where
         # is_nullable() is needed to the compiler stage, but that is not easy
         # to do currently.
-        if connections[DEFAULT_DB_ALIAS].features.interprets_empty_strings_as_nulls and field.empty_strings_allowed:
+        return (
-            return True
+            connections[DEFAULT_DB_ALIAS].features.interprets_empty_strings_as_nulls and
-        else:
+            field.empty_strings_allowed
-            return field.null
+        ) or field.null
 
 
 def get_order_dir(field, default='ASC'):

django/forms/boundfield.py

@@ -79,12 +79,9 @@ class BoundField:
         attributes passed as attrs. If a widget isn't specified, use the
         field's default widget.
         """
-        if not widget:
+        widget = widget or self.field.widget
-            widget = self.field.widget
-
         if self.field.localize:
             widget.is_localized = True
-
         attrs = attrs or {}
         attrs = self.build_widget_attrs(attrs, widget)
         if self.auto_id and 'id' not in widget.attrs:
@@ -219,8 +216,7 @@ class BoundField:
         return data
 
     def build_widget_attrs(self, attrs, widget=None):
-        if not widget:
+        widget = widget or self.field.widget
-            widget = self.field.widget
         attrs = dict(attrs)  # Copy attrs to avoid modifying the argument.
         if widget.use_required_attribute(self.initial) and self.field.required and self.form.use_required_attribute:
             attrs['required'] = True

django/forms/fields.py

@@ -591,11 +591,7 @@ class FileField(Field):
         return data
 
     def has_changed(self, initial, data):
-        if self.disabled:
+        return not self.disabled and data is not None
-            return False
-        if data is None:
-            return False
-        return True
 
 
 class ImageField(FileField):

django/http/request.py

@@ -376,19 +376,17 @@ class QueryDict(MultiValueDict):
 
     def __init__(self, query_string=None, mutable=False, encoding=None):
         super().__init__()
-        if not encoding:
+        self.encoding = encoding or settings.DEFAULT_CHARSET
-            encoding = settings.DEFAULT_CHARSET
-        self.encoding = encoding
         query_string = query_string or ''
         parse_qsl_kwargs = {
             'keep_blank_values': True,
             'fields_limit': settings.DATA_UPLOAD_MAX_NUMBER_FIELDS,
-            'encoding': encoding,
+            'encoding': self.encoding,
         }
         if isinstance(query_string, bytes):
             # query_string normally contains URL-encoded data, a subset of ASCII.
             try:
-                query_string = query_string.decode(encoding)
+                query_string = query_string.decode(self.encoding)
             except UnicodeDecodeError:
                 # ... but some user agents are misbehaving :-(
                 query_string = query_string.decode('iso-8859-1')

django/middleware/http.py

@@ -23,8 +23,7 @@ class ConditionalGetMiddleware(MiddlewareMixin):
 
         etag = response.get('ETag')
         last_modified = response.get('Last-Modified')
-        if last_modified:
+        last_modified = last_modified and parse_http_date_safe(last_modified)
-            last_modified = parse_http_date_safe(last_modified)
 
         if etag or last_modified:
             return get_conditional_response(

django/test/client.py

@@ -236,8 +236,7 @@ def encode_file(boundary, key, file):
 
     if content_type is None:
         content_type = 'application/octet-stream'
-    if not filename:
+    filename = filename or key
-        filename = key
     return [
         to_bytes('--%s' % boundary),
         to_bytes('Content-Disposition: form-data; name="%s"; filename="%s"'

django/test/html.py

@@ -69,9 +69,7 @@ class Element:
                     other_value = other_attr
                 if attr != other_attr or value != other_value:
                     return False
-        if self.children != element.children:
+        return self.children == element.children
-            return False
-        return True
 
     def __hash__(self):
         return hash((self.name,) + tuple(a for a in self.attributes))

django/test/utils.py

@@ -50,9 +50,7 @@ class Approximate:
         return repr(self.val)
 
     def __eq__(self, other):
-        if self.val == other:
+        return self.val == other or round(abs(self.val - other), self.places) == 0
-            return True
-        return round(abs(self.val - other), self.places) == 0
 
 
 class ContextList(list):
@@ -300,9 +298,7 @@ def teardown_databases(old_config, verbosity, parallel=0, keepdb=False):
 
 
 def get_runner(settings, test_runner_class=None):
-    if not test_runner_class:
+    test_runner_class = test_runner_class or settings.TEST_RUNNER
-        test_runner_class = settings.TEST_RUNNER
-
     test_path = test_runner_class.split('.')
     # Allow for relative paths
     if len(test_path) > 1:

django/urls/resolvers.py

@@ -393,9 +393,7 @@ class URLResolver:
         warnings = []
         for pattern in self.url_patterns:
             warnings.extend(check_resolver(pattern))
-        if not warnings:
+        return warnings or self.pattern.check()
-            warnings = self.pattern.check()
-        return warnings
 
     def _populate(self):
         # Short-circuit if called recursively in this thread to prevent

django/utils/cache.py

@@ -142,12 +142,10 @@ def get_conditional_response(request, etag=None, last_modified=None, response=No
     # Get HTTP request headers.
     if_match_etags = parse_etags(request.META.get('HTTP_IF_MATCH', ''))
     if_unmodified_since = request.META.get('HTTP_IF_UNMODIFIED_SINCE')
-    if if_unmodified_since:
+    if_unmodified_since = if_unmodified_since and parse_http_date_safe(if_unmodified_since)
-        if_unmodified_since = parse_http_date_safe(if_unmodified_since)
     if_none_match_etags = parse_etags(request.META.get('HTTP_IF_NONE_MATCH', ''))
     if_modified_since = request.META.get('HTTP_IF_MODIFIED_SINCE')
-    if if_modified_since:
+    if_modified_since = if_modified_since and parse_http_date_safe(if_modified_since)
-        if_modified_since = parse_http_date_safe(if_modified_since)
 
     # Step 1 of section 6 of RFC 7232: Test the If-Match precondition.
     if if_match_etags and not _if_match_passes(etag, if_match_etags):

django/utils/crypto.py

@@ -78,8 +78,7 @@ def pbkdf2(password, salt, iterations, dklen=0, digest=None):
     """Return the hash of password using pbkdf2."""
     if digest is None:
         digest = hashlib.sha256
-    if not dklen:
+    dklen = dklen or None
-        dklen = None
     password = force_bytes(password)
     salt = force_bytes(salt)
     return hashlib.pbkdf2_hmac(digest().name, password, salt, iterations, dklen)

django/utils/dateparse.py

@@ -89,8 +89,7 @@ def parse_time(value):
     match = time_re.match(value)
     if match:
         kw = match.groupdict()
-        if kw['microsecond']:
+        kw['microsecond'] = kw['microsecond'] and kw['microsecond'].ljust(6, '0')
-            kw['microsecond'] = kw['microsecond'].ljust(6, '0')
         kw = {k: int(v) for k, v in kw.items() if v is not None}
         return datetime.time(**kw)
 
@@ -107,8 +106,7 @@ def parse_datetime(value):
     match = datetime_re.match(value)
     if match:
         kw = match.groupdict()
-        if kw['microsecond']:
+        kw['microsecond'] = kw['microsecond'] and kw['microsecond'].ljust(6, '0')
-            kw['microsecond'] = kw['microsecond'].ljust(6, '0')
         tzinfo = kw.pop('tzinfo')
         if tzinfo == 'Z':
             tzinfo = utc

django/utils/deprecation.py

@@ -88,8 +88,7 @@ class MiddlewareMixin:
         response = None
         if hasattr(self, 'process_request'):
             response = self.process_request(request)
-        if not response:
+        response = response or self.get_response(request)
-            response = self.get_response(request)
         if hasattr(self, 'process_response'):
             response = self.process_response(request, response)
         return response

django/utils/feedgenerator.py

@@ -86,8 +86,7 @@ class SyndicationFeed:
                  feed_url=None, feed_copyright=None, feed_guid=None, ttl=None, **kwargs):
         def to_str(s):
             return str(s) if s is not None else s
-        if categories:
+        categories = categories and [str(c) for c in categories]
-            categories = [str(c) for c in categories]
         self.feed = {
             'title': to_str(title),
             'link': iri_to_uri(link),
@@ -117,8 +116,7 @@ class SyndicationFeed:
         """
         def to_str(s):
             return str(s) if s is not None else s
-        if categories:
+        categories = categories and [to_str(c) for c in categories]
-            categories = [to_str(c) for c in categories]
         self.items.append({
             'title': to_str(title),
             'link': iri_to_uri(link),

django/utils/numberformat.py

@@ -42,8 +42,7 @@ def format(number, decimal_sep, decimal_pos=None, grouping=0, thousand_sep='',
         int_part, dec_part = str_number, ''
     if decimal_pos is not None:
         dec_part = dec_part + ('0' * (decimal_pos - len(dec_part)))
-    if dec_part:
+    dec_part = dec_part and decimal_sep + dec_part
-        dec_part = decimal_sep + dec_part
     # grouping
     if use_grouping:
         try:

django/utils/timesince.py

@@ -35,8 +35,7 @@ def timesince(d, now=None, reversed=False):
     if now and not isinstance(now, datetime.datetime):
         now = datetime.datetime(now.year, now.month, now.day)
 
-    if not now:
+    now = now or datetime.datetime.now(utc if is_aware(d) else None)
-        now = datetime.datetime.now(utc if is_aware(d) else None)
 
     if reversed:
         d, now = now, d

django/views/i18n.py

@@ -35,8 +35,7 @@ def set_language(request):
     if ((next or not request.is_ajax()) and
             not is_safe_url(url=next, allowed_hosts={request.get_host()}, require_https=request.is_secure())):
         next = request.META.get('HTTP_REFERER')
-        if next:
+        next = next and unquote(next)  # HTTP_REFERER may be encoded.
-            next = unquote(next)  # HTTP_REFERER may be encoded.
         if not is_safe_url(url=next, allowed_hosts={request.get_host()}, require_https=request.is_secure()):
             next = '/'
     response = HttpResponseRedirect(next) if next else HttpResponse(status=204)

tests/auth_tests/test_auth_backends.py

@@ -339,9 +339,7 @@ class SimpleRowlevelBackend:
         return False
 
     def has_module_perms(self, user, app_label):
-        if not user.is_anonymous and not user.is_active:
+        return (user.is_anonymous or user.is_active) and app_label == 'app1'
-            return False
-        return app_label == "app1"
 
     def get_all_permissions(self, user, obj=None):
         if not obj:

tests/fixtures/tests.py

@@ -51,8 +51,7 @@ class DumpDataAssertMixin:
                          natural_foreign_keys=False, natural_primary_keys=False,
                          use_base_manager=False, exclude_list=[], primary_keys=''):
         new_io = StringIO()
-        if filename:
+        filename = filename and os.path.join(tempfile.gettempdir(), filename)
-            filename = os.path.join(tempfile.gettempdir(), filename)
         management.call_command('dumpdata', *args, **{'format': format,
                                                       'stdout': new_io,
                                                       'stderr': new_io,

tests/gis_tests/test_data.py

@@ -62,10 +62,7 @@ class TestGeom(TestObj):
             self.coords = tuplize(coords)
         if centroid:
             self.centroid = tuple(centroid)
-        if ext_ring_cs:
+        self.ext_ring_cs = ext_ring_cs and tuplize(ext_ring_cs)
-            ext_ring_cs = tuplize(ext_ring_cs)
-        self.ext_ring_cs = ext_ring_cs
-
         super().__init__(**kwargs)
 
 

tests/multiple_database/routers.py

@@ -43,9 +43,7 @@ class AuthRouter:
 
     def allow_relation(self, obj1, obj2, **hints):
         "Allow any relation if a model in Auth is involved"
-        if obj1._meta.app_label == 'auth' or obj2._meta.app_label == 'auth':
+        return obj1._meta.app_label == 'auth' or obj2._meta.app_label == 'auth' or None
-            return True
-        return None
 
     def allow_migrate(self, db, app_label, **hints):
         "Make sure the auth app only appears on the 'other' db"