misc: fix warning about unclosed resource in import-site (#53577)

combo/data/management/commands/import_site.py

@@ -14,6 +14,7 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+import contextlib
 import json
 import sys
 import tarfile
@@ -35,28 +36,32 @@ class Command(BaseCommand):
         parser.add_argument('--overwrite', action='store_true', default=False, help='Overwrite asset files')
 
     def handle(self, filename, *args, **options):
-        if filename == '-':
-            format = 'json'
-            fd = sys.stdin
-        else:
-            try:
-                fd = open(filename, 'rb')
-            except IOError as e:
-                raise CommandError(e)
-            try:
-                tarfile.open(mode='r', fileobj=fd)
-            except tarfile.TarError as e:
+        with contextlib.ExitStack() as stack:
+            if filename == '-':
                 format = 'json'
-                fd = open(filename, 'r')
+                fd = sys.stdin
             else:
-                format = 'tar'
-                fd = open(filename, 'rb')
-        try:
-            if format == 'json':
-                import_site(json.load(fd), if_empty=options['if_empty'], clean=options['clean'])
-            else:
-                import_site_tar(
-                    fd, if_empty=options['if_empty'], clean=options['clean'], overwrite=options['overwrite']
-                )
-        except ImportSiteError as e:
-            raise CommandError(e)
+                try:
+                    fd = stack.enter_context(open(filename, 'rb'))
+                except IOError as e:
+                    raise CommandError(e)
+                try:
+                    tarfile.open(mode='r', fileobj=fd)
+                except tarfile.TarError as e:
+                    format = 'json'
+                    fd = open(filename, 'r')
+                else:
+                    format = 'tar'
+                    fd = open(filename, 'rb')
+            try:
+                if format == 'json':
+                    import_site(json.load(fd), if_empty=options['if_empty'], clean=options['clean'])
+                else:
+                    import_site_tar(
+                        fd,
+                        if_empty=options['if_empty'],
+                        clean=options['clean'],
+                        overwrite=options['overwrite'],
+                    )
+            except ImportSiteError as e:
+                raise CommandError(e)