What version are you running?
v2.5.4
What's the URL of the page containing the problem?
<private reviewboard instance>/r/2463
What steps will reproduce the problem?

Upgrade from reviewboard 1.6 to 1.7 to 2.0 to 2.5.4
Open a review containing binary files






What is the expected output? What do you see instead?
The review request should be shown. Instead you see 
Something broke! (Error 500)
It appears something broke when you tried to go to here. This is either a bug in Review Board or a server configuration error. Please report this to your administrator. 
What operating system are you using? What browser?
Win7, Firefox 46.0.1

Reviewboard running on Ubuntu 12.04

Apache 2.2.22

mod-wsgi

Python 2.7
Please provide any additional information below.
Log:

2016-05-17 20:01:58,430 - DEBUG -  - Migrating LegacyFileDiffData 2b4d9451221f9a3daea370e050cceee4aec9e14f to RawFileDiffData for diff in FileDiff 148740

2016-05-17 20:01:58,537 - DEBUG -  - Recalculating insert/delete line counts on RawFileDiffData 1704

2016-05-17 20:01:58,537 - DEBUG -  - DiffParser.parse: Beginning parse of diff, size = 93

2016-05-17 20:01:58,538 - ERROR -  - Exception thrown for user  at /r/2463/
list index out of range

Traceback (most recent call last):

  File "/usr/local/lib/python2.7/dist-packages/Django-1.6.11-py2.7.egg/django/core/handlers/base.py", line 112, in get_response

    response = wrapped_callback(request, callback_args, callback_kwargs)

  File "/usr/local/lib/python2.7/dist-packages/ReviewBoard-2.5.4-py2.7.egg/reviewboard/accounts/decorators.py", line 23, in _check

    return login_required(view_func)(*args, kwargs)

  File "/usr/local/lib/python2.7/dist-packages/Django-1.6.11-py2.7.egg/django/contrib/auth/decorators.py", line 22, in _wrapped_view

    return view_func(request, args, kwargs)

  File "/usr/local/lib/python2.7/dist-packages/ReviewBoard-2.5.4-py2.7.egg/reviewboard/site/decorators.py", line 35, in _check

    return view_func(request, local_site=local_site, *args, kwargs)

  File "/usr/local/lib/python2.7/dist-packages/ReviewBoard-2.5.4-py2.7.egg/reviewboard/reviews/views.py", line 728, in review_detail

    changedesc.fields_changed[field_id])

  File "/usr/local/lib/python2.7/dist-packages/ReviewBoard-2.5.4-py2.7.egg/reviewboard/reviews/fields.py", line 264, in get_change_entry_sections_html

    'rendered_html': mark_safe(self.render_change_entry_html(info)),

  File "/usr/local/lib/python2.7/dist-packages/ReviewBoard-2.5.4-py2.7.egg/reviewboard/reviews/builtin_fields.py", line 475, in render_change_entry_html

    counts = diffset.get_total_line_counts()

  File "/usr/local/lib/python2.7/dist-packages/ReviewBoard-2.5.4-py2.7.egg/reviewboard/diffviewer/models.py", line 518, in get_total_line_counts

    for key, value in six.iteritems(filediff.get_line_counts()):

  File "/usr/local/lib/python2.7/dist-packages/ReviewBoard-2.5.4-py2.7.egg/reviewboard/diffviewer/models.py", line 287, in get_line_counts

    self._migrate_diff_data()

  File "/usr/local/lib/python2.7/dist-packages/ReviewBoard-2.5.4-py2.7.egg/reviewboard/diffviewer/models.py", line 432, in _migrate_diff_data

    self._recalculate_line_counts(self.diff_hash)

  File "/usr/local/lib/python2.7/dist-packages/ReviewBoard-2.5.4-py2.7.egg/reviewboard/diffviewer/models.py", line 477, in _recalculate_line_counts

    self.diffset.repository.get_scmtool())

  File "/usr/local/lib/python2.7/dist-packages/ReviewBoard-2.5.4-py2.7.egg/reviewboard/diffviewer/models.py", line 100, in recalculate_line_counts

    files = tool.get_parser(self.content).parse()

  File "/usr/local/lib/python2.7/dist-packages/ReviewBoard-2.5.4-py2.7.egg/reviewboard/diffviewer/parser.py", line 59, in parse

    next_linenum, new_file = self.parse_change_header(i)

  File "/usr/local/lib/python2.7/dist-packages/ReviewBoard-2.5.4-py2.7.egg/reviewboard/diffviewer/parser.py", line 101, in parse_change_header

    linenum = self.parse_diff_header(linenum, info)

  File "/usr/local/lib/python2.7/dist-packages/ReviewBoard-2.5.4-py2.7.egg/reviewboard/scmtools/hg.py", line 136, in parse_diff_header

    self.lines[linenum].startswith(b"Binary file ")):

IndexError: list index out of range



The offending legacy file diff data (2b4d9451221f9a3daea370e050cceee4aec9e14f) contains 
ZGlmZiAtciBhYjZiNGIwOGZhNDAgLXIgNTU5NDgzMmE5MGE1IFdpbmxvZy9IcmguV2lubG9nLlZpZXcvSW1hZ2VzL1NtYWxsL0hvcml6b250YWxHdWlkZS5wbmcK
which decoded is
diff -r ab6b4b08fa40 -r 5594832a90a5 Winlog/Hrh.Winlog.View/Images/Small/HorizontalGuide.png
The diff contains no data because the file that changed was a binary file.