Cannot operate on closed cursor

[Ryan J Ollos]

While testing with Trac 0.11, I've seen the following in the logs:

11:17:19 AM Trac[main] ERROR: Cannot operate on a closed cursor.
Traceback (most recent call last):
  File "/home/user/Workspace/th11043/trac-0.11/trac/web/main.py", line 233, in dispatch
    self._post_process_request(req)
  File "/home/user/Workspace/th11043/trac-0.11/trac/web/main.py", line 301, in _post_process_request
    f.post_process_request(req, *(None,)*extra_arg_count)
  File "/home/user/Workspace/trachacks.git/bookmarkplugin/trunk/tracbookmark/__init__.py", line 183, in post_process_request
    self.render_bookmarker(req)
  File "/home/user/Workspace/trachacks.git/bookmarkplugin/trunk/tracbookmark/__init__.py", line 335, in render_bookmarker
    menu = self._get_bookmarks_menu(req)
  File "/home/user/Workspace/trachacks.git/bookmarkplugin/trunk/tracbookmark/__init__.py", line 342, in _get_bookmarks_menu
    for url, name, username in self.get_bookmarks(req):
  File "/home/user/Workspace/th11043/trac-0.11/trac/db/util.py", line 40, in __iter__
    row = self.cursor.fetchone()
ProgrammingError: Cannot operate on a closed cursor.

The error occurs when loading any page, such as WikiStart. I think we shouldn't be returning a cursor from get_bookmarks.

[Jun Omae]

Indeed. We must keep the db variable while in use of cursor. See ​https://groups.google.com/forum/?fromgroups#!msg/trac-dev/trRtzv5waoQ/Uz1T1sBhTR8J and ​http://trac.edgewall.org/changeset/8878.

tracbookmark/__init__.py

@@ -61 +61 @@
         cursor.execute(
             "SELECT resource, name, username FROM bookmarks WHERE username=%s",
             (get_reporter_id(req),))
-        return cursor
+        for row in cursor:
+            yield row
 
     def get_bookmark(self, req, resource):
         """Return the current users bookmark for a resource."""

[Ryan J Ollos]

Thanks! Initially I had just called fetchall on the cursor, but returning an iterator is probably better.

[Ryan J Ollos]

(In [13227]) Fixes #11115: Avoid Cannot operate on closed cursor errors by not returning a cursor from a function.