Adapted fixture read mode to file type

Binary mode added in ed532a6a1e is not supported by ZipFile.
Refs #22399.

django/core/management/commands/loaddata.py

@@ -76,13 +76,14 @@ class Command(BaseCommand):
         self.models = set()
 
         self.serialization_formats = serializers.get_public_serializer_formats()
+        # Forcing binary mode may be revisited after dropping Python 2 support (see #22399)
         self.compression_formats = {
-            None: open,
-            'gz': gzip.GzipFile,
-            'zip': SingleZipReader
+            None: (open, 'rb'),
+            'gz': (gzip.GzipFile, 'rb'),
+            'zip': (SingleZipReader, 'r'),
         }
         if has_bz2:
-            self.compression_formats['bz2'] = bz2.BZ2File
+            self.compression_formats['bz2'] = (bz2.BZ2File, 'r')
 
         with connection.constraint_checks_disabled():
             for fixture_label in fixture_labels:
@@ -124,9 +125,8 @@ class Command(BaseCommand):
         """
         for fixture_file, fixture_dir, fixture_name in self.find_fixtures(fixture_label):
             _, ser_fmt, cmp_fmt = self.parse_name(os.path.basename(fixture_file))
-            open_method = self.compression_formats[cmp_fmt]
-            # Forcing binary mode may be revisited after dropping Python 2 support (see #22399)
-            fixture = open_method(fixture_file, 'rb')
+            open_method, mode = self.compression_formats[cmp_fmt]
+            fixture = open_method(fixture_file, mode)
             try:
                 self.fixture_count += 1
                 objects_in_fixture = 0