[3.0.x] Fixed #31240 -- Properly closed FileResponse when wsgi.file_wrapper is used.

Thanks to Oskar Persson for the report.

Backport of 41a3b3d18647b258331104520e76f977406c590d from master

3 files changed, 12 insertions, 6 deletions

diff --git a/django/core/handlers/base.py b/django/core/handlers/base.py
index 2304e7761d..a7b8e61f60 100644
--- a/django/core/handlers/base.py
+++ b/django/core/handlers/base.py
@@ -73,7 +73,7 @@ class BaseHandler:
         # Setup default url resolver for this thread
         set_urlconf(settings.ROOT_URLCONF)
         response = self._middleware_chain(request)
-        response._closable_objects.append(request)
+        response._resource_closers.append(request.close)
         if response.status_code >= 400:
             log_response(
                 '%s: %s', response.reason_phrase, request.path,
diff --git a/django/core/handlers/wsgi.py b/django/core/handlers/wsgi.py
index cb740e5c50..4dff1a299b 100644
--- a/django/core/handlers/wsgi.py
+++ b/django/core/handlers/wsgi.py
@@ -141,6 +141,10 @@ class WSGIHandler(base.BaseHandler):
         ]
         start_response(status, response_headers)
         if getattr(response, 'file_to_stream', None) is not None and environ.get('wsgi.file_wrapper'):
+            # If `wsgi.file_wrapper` is used the WSGI server does not call
+            # .close on the response, but on the file wrapper. Patch it to use
+            # response.close instead which takes care of closing all files.
+            response.file_to_stream.close = response.close
             response = environ['wsgi.file_wrapper'](response.file_to_stream, response.block_size)
         return response
 
diff --git a/django/http/response.py b/django/http/response.py
index 04efbd6bef..c33feb97c4 100644
--- a/django/http/response.py
+++ b/django/http/response.py
@@ -40,7 +40,7 @@ class HttpResponseBase:
         # the header (required for working with legacy systems) and the header
         # value. Both the name of the header and its value are ASCII strings.
         self._headers = {}
-        self._closable_objects = []
+        self._resource_closers = []
         # This parameter is set by the handler. It's necessary to preserve the
         # historical behavior of request_finished.
         self._handler_class = None
@@ -242,11 +242,13 @@ class HttpResponseBase:
     # The WSGI server must call this method upon completion of the request.
     # See http://blog.dscpl.com.au/2012/10/obligations-for-calling-close-on.html
     def close(self):
-        for closable in self._closable_objects:
+        for closer in self._resource_closers:
             try:
-                closable.close()
+                closer()
             except Exception:
                 pass
+        # Free resources that were still referenced.
+        self._resource_closers.clear()
         self.closed = True
         signals.request_finished.send(sender=self._handler_class)
 
@@ -377,7 +379,7 @@ class StreamingHttpResponse(HttpResponseBase):
         # Ensure we can never iterate on "value" more than once.
         self._iterator = iter(value)
         if hasattr(value, 'close'):
-            self._closable_objects.append(value)
+            self._resource_closers.append(value.close)
 
     def __iter__(self):
         return self.streaming_content
@@ -404,7 +406,7 @@ class FileResponse(StreamingHttpResponse):
 
         self.file_to_stream = filelike = value
         if hasattr(filelike, 'close'):
-            self._closable_objects.append(filelike)
+            self._resource_closers.append(filelike.close)
         value = iter(lambda: filelike.read(self.block_size), b'')
         self.set_headers(filelike)
         super()._set_streaming_content(value)