Fix error when not selecting a file for upload in Files and Images (#497

)

* Fix error when not selecting a file for upload in Files and Images

* - under Python 2 that ValueError is not thrown. Sigh.

CHANGES.rst

@@ -17,6 +17,9 @@ Fixes
 - Fix handling of DTML in Ace editor
   (`#489 <https://github.com/zopefoundation/Zope/issues/489>`_)
 
+- Fix error when not selecting a file for upload in Files and Images
+  (`#492 <https://github.com/zopefoundation/Zope/issues/492>`_)
+
 
 4.0b9 (2019-02-09)
 ------------------

src/OFS/Image.py

@@ -553,17 +553,19 @@ def manage_upload(self, file='', REQUEST=None):
         if self.wl_isLocked():
             raise ResourceLockedError("File is locked.")
 
-        data, size = self._read_data(file)
-        content_type = self._get_content_type(file, data, self.__name__,
-                                              'application/octet-stream')
-        self.update_data(data, content_type, size)
-
-        notify(ObjectModifiedEvent(self))
+        if file:
+            data, size = self._read_data(file)
+            content_type = self._get_content_type(file, data, self.__name__,
+                                                  'application/octet-stream')
+            self.update_data(data, content_type, size)
+            notify(ObjectModifiedEvent(self))
+            msg = 'Saved changes.'
+        else:
+            msg = 'Please select a file to upload.'
 
         if REQUEST:
-            message = "Saved changes."
             return self.manage_main(
-                self, REQUEST, manage_tabs_message=message)
+                self, REQUEST, manage_tabs_message=msg)
 
     def _get_content_type(self, file, body, id, content_type=None):
         headers = getattr(file, 'headers', None)

src/OFS/tests/testFileAndImage.py

@@ -228,6 +228,10 @@ def testManageUpload(self):
         self.assertEqual(1, len(self.eventCatcher.modified))
         self.assertTrue(self.eventCatcher.modified[0].object is self.file)
 
+    def testManageUploadWithoutFileData(self):
+        self.file.manage_upload()
+        self.assertEqual(0, len(self.eventCatcher.modified))
+
     def testIfModSince(self):
         now = time.time()
         e = {'SERVER_NAME': 'foo',