What version are you running?
ReviewBoard-2.5

Djblets-0.9

Django-1.6.11
What's the URL of the page containing the problem?
/r/
What steps will reproduce the problem?

Go to review requests page
Note that all the summaries say "None"


What is the expected output? What do you see instead?
Expected: Summary of each review request

Actual: "None"
What operating system are you using? What browser?
Linux, Firefox

Please provide any additional information below.
This error appears in the logs:
[Mon Nov 02 12:27:30 2015] [error] ERROR:root:Error when calling render_data for DataGrid Column <reviewboard.datagrids.columns.SummaryColumn object at 0x12d2b0d0>: zero length field name in format

[Mon Nov 02 12:27:30 2015] [error] Traceback (most recent call last):

[Mon Nov 02 12:27:30 2015] [error]   File "/usr/lib/python2.6/site-packages/Djblets-0.9-py2.6.egg/djblets/datagrid/grids.py", line 447, in render_cell

[Mon Nov 02 12:27:30 2015] [error]     rendered_data = self.render_data(state, obj)

[Mon Nov 02 12:27:30 2015] [error]   File "/usr/lib/python2.6/site-packages/ReviewBoard-2.5-py2.6.egg/reviewboard/datagrids/columns.py", line 678, in render_data

[Mon Nov 02 12:27:30 2015] [error]     display_data += format_html('<span>{}</span>', summary)

[Mon Nov 02 12:27:30 2015] [error]   File "/usr/lib/python2.6/site-packages/Django-1.6.11-py2.6.egg/django/utils/html.py", line 82, in format_html

[Mon Nov 02 12:27:30 2015] [error]     return mark_safe(format_string.format(args_safe, *kwargs_safe))

[Mon Nov 02 12:27:30 2015] [error] ValueError: zero length field name in format
The issue is in SummaryColumn.render_data:
    display_data = format_html_join(
        '', '<label class="{}">{}</label>', labels)

    if summary:
        display_data += format_html('<span>{}</span>', summary)
    else:
        display_data += format_html('<span class="no-summary">{}</span>',
                                    _('No Summary'))


django.utils.format.format_html is complaining that "{}" has no field name. Changing it to "{0}" fixes the error.
    display_data = format_html_join(
        '', '<label class="{0}">{0}</label>', labels)

    if summary:
        display_data += format_html('<span>{0}</span>', summary)
    else:
        display_data += format_html('<span class="no-summary">{0}</span>',
                                    _('No Summary'))