HTTPRequest: close file uploads to prevent ResourceWarning (#1243)

* testHTTPRequest: use larger file for test_processInputs_w_large_input_gets_tempfile

This test was not using a large enough file to use temporary file, but
the test was not really asserting that a temporary file was used.

* HTTPRequest: close file uploads to prevent ResourceWarning

CHANGES.rst

@@ -10,6 +10,9 @@ https://github.com/zopefoundation/Zope/blob/4.x/CHANGES.rst
 5.11.2 (unreleased)
 -------------------
 
+- Fix a ``ResourceWarning`` emitted when uploading large files.
+  (`#1242 <https://github.com/zopefoundation/Zope/issues/1242>`_)
+
 - OFS/cachable: fix *Cache this object using* label in ZMI.
 
 - Include versions constraints for production and non-production dependencies

src/ZPublisher/HTTPRequest.py

@@ -192,6 +192,9 @@ def clear(self):
         self.stdin = None
         self._file = None
         self._fs = None
+        for f in self.form.values():
+            if isinstance(f, FileUpload):
+                f.close()
         self.form.clear()
         # we want to clear the lazy dict here because BaseRequests don't have
         # one.  Without this, there's the possibility of memory leaking

src/ZPublisher/tests/testHTTPRequest.py

@@ -901,8 +901,10 @@ def test_processInputs_w_large_input_gets_tempfile(self):
         req.processInputs()
         f = req.form.get('largefile')
         self.assertTrue(f.name)
-        self.assertEqual(4006, len(f.file.read()))
-        f.file.close()
+        self.assertEqual(40006, len(f.file.read()))
+        self.assertTrue(f.file.fileno())
+        req.clear()
+        self.assertTrue(f.file.closed)
 
     def test_processInputs_with_file_upload_gets_iterator(self):
         # checks fileupload object supports the iterator protocol
@@ -1640,7 +1642,7 @@ def __init__(self, file):
 test %s
 
 --12345--
-''' % (b'test' * 1000)
+''' % (b'test' * 10000)
 
 TEST_ISSUE_1095_DATA = b'''
 --12345