Very slow behavior with QTreeWidget on 8.10

[Carlos Scheidegger]

Binary package hint: python-qt4

The bug happens when QTreeWidget.expandAll is called. The documentation warns that expandAll might be slow, but the call itself is not the problem. The slowdown happens when the user collapses the toplevel treewidgetitem and then reexpands it. The same behavior appears on Ubuntu 8.10 32 and 64-bit. Where this problem is not present, expanding and collapsing the treewidgetitem is very fast.

This bug is NOT present on 8.04. Additionally, with manually built versions of PyQt and Qt, the problem also does not manifest itself.

I'm attaching a small script that reproduces the problem. To exercise the bug, run the script and doubleclick the "toplevel" item. The item should collapse, quickly. Then, doubleclick it again to expand it. This will take a *long* time (on the order of minutes). On a machine that does not experience the issue, this expansion is essentially instant.

Here's the information on my system, and relevant package versions.

$ lsb_release -rd
Description: Ubuntu 8.10
Release: 8.10

$ apt-cache policy python-qt4
python-qt4:
  Installed: 4.4.3-1ubuntu1
  Candidate: 4.4.3-1ubuntu1
  Version table:
 *** 4.4.3-1ubuntu1 0
        500 http://us.archive.ubuntu.com intrepid/main Packages
        100 /var/lib/dpkg/status

$ apt-cache policy libqtcore4
libqtcore4:
  Installed: 4.4.3-0ubuntu1.1
  Candidate: 4.4.3-0ubuntu1.1
  Version table:
 *** 4.4.3-0ubuntu1.1 0
        500 http://us.archive.ubuntu.com intrepid-updates/main Packages
        100 /var/lib/dpkg/status
     4.4.3-0ubuntu1 0
        500 http://us.archive.ubuntu.com intrepid/main Packages

$ apt-cache policy libqtgui4
libqtgui4:
  Installed: 4.4.3-0ubuntu1.1
  Candidate: 4.4.3-0ubuntu1.1
  Version table:
 *** 4.4.3-0ubuntu1.1 0
        500 http://us.archive.ubuntu.com intrepid-updates/main Packages
        100 /var/lib/dpkg/status
     4.4.3-0ubuntu1 0
        500 http://us.archive.ubuntu.com intrepid/main Packages