[extensions-web] Guard against a new extension with no old version in the review page

[Jasper St. Pierre <jstpierre src gnome org>]

commit 85426446788c9e9839c5f387ed1cdb7b2ece087a
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Tue Nov 15 17:45:59 2011 -0500

    Guard against a new extension with no old version in the review page

 sweettooth/review/templates/review/review.html |    2 ++
 sweettooth/review/views.py                     |   10 ++++++++++
 2 files changed, 12 insertions(+), 0 deletions(-)
---
diff --git a/sweettooth/review/templates/review/review.html b/sweettooth/review/templates/review/review.html
index e2b298e..56d3ce3 100644
--- a/sweettooth/review/templates/review/review.html
+++ b/sweettooth/review/templates/review/review.html
@@ -31,9 +31,11 @@
 <div id="files" data-pk="{{ version.pk }}">
 </div>
 
+{% if previous_versions %}
 <h2 class="expanded"> Diff Against Previous Version </h2>
 <div id="diff" data-pk="{{ version.pk }}">
 </div>
+{% endif %}
 
 <h2 class="expanded"> Previous Versions </h2>
 <div id="previous_versions">
diff --git a/sweettooth/review/views.py b/sweettooth/review/views.py
index 15567e3..7a88544 100644
--- a/sweettooth/review/views.py
+++ b/sweettooth/review/views.py
@@ -86,6 +86,10 @@ def get_zipfiles(version):
     extension = version.extension
 
     new_zipfile = version.get_zipfile('r')
+
+    if extension.latest_version is None:
+        return None, new_zipfile
+
     old_zipfile = extension.latest_version.get_zipfile('r')
 
     return old_zipfile, new_zipfile
@@ -124,6 +128,12 @@ def ajax_get_file_list_view(request, obj):
     old_zipfile, new_zipfile = get_zipfiles(version)
 
     new_filelist = set(new_zipfile.namelist())
+
+    if old_zipfile is None:
+        return dict(both=[],
+                    added=sorted(new_zipfile.namelist()),
+                    deleted=[])
+
     old_filelist = set(old_zipfile.namelist())
 
     both    = new_filelist & old_filelist