Handle deleted wiki page versions (#10852).

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@10684 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/wiki_content.rb

@@ -115,10 +115,18 @@ class WikiContent < ActiveRecord::Base
 
     # Returns the previous version or nil
     def previous
-      @previous ||= WikiContent::Version.find(:first,
-                                              :order => 'version DESC',
-                                              :include => :author,
-                                              :conditions => ["wiki_content_id = ? AND version < ?", wiki_content_id, version])
+      @previous ||= WikiContent::Version.
+        reorder('version DESC').
+        includes(:author).
+        where("wiki_content_id = ? AND version < ?", wiki_content_id, version).first
+    end
+
+    # Returns the next version or nil
+    def next
+      @next ||= WikiContent::Version.
+        reorder('version ASC').
+        includes(:author).
+        where("wiki_content_id = ? AND version > ?", wiki_content_id, version).first
     end
   end
 end

app/models/wiki_page.rb

@@ -111,11 +111,12 @@ class WikiPage < ActiveRecord::Base
 
   def diff(version_to=nil, version_from=nil)
     version_to = version_to ? version_to.to_i : self.content.version
-    version_from = version_from ? version_from.to_i : version_to - 1
-    version_to, version_from = version_from, version_to unless version_from < version_to
-
     content_to = content.versions.find_by_version(version_to)
-    content_from = content.versions.find_by_version(version_from)
+    content_from = version_from ? content.versions.find_by_version(version_from.to_i) : content_to.previous
+
+    if content_from.version > content_to.version
+      content_to, content_from = content_from, content_to
+    end
 
     (content_to && content_from) ? WikiDiff.new(content_to, content_from) : nil
   end

app/views/wiki/show.html.erb

@@ -17,14 +17,14 @@
     <p>
     <%= link_to(("\xc2\xab " + l(:label_previous)),
                 :action => 'show', :id => @page.title, :project_id => @page.project,
-                :version => (@content.version - 1)) + " - " if @content.version > 1 %>
+                :version => @content.previous.version) + " - " if @content.previous %>
     <%= "#{l(:label_version)} #{@content.version}/#{@page.content.version}" %>
     <%= '('.html_safe + link_to(l(:label_diff), :controller => 'wiki', :action => 'diff',
                       :id => @page.title, :project_id => @page.project,
-                      :version => @content.version) + ')'.html_safe if @content.version > 1 %> - 
+                      :version => @content.version) + ')'.html_safe if @content.previous %> - 
     <%= link_to((l(:label_next) + " \xc2\xbb"), :action => 'show',
                 :id => @page.title, :project_id => @page.project,
-                :version => (@content.version + 1)) + " - " if @content.version < @page.content.version %>
+                :version => @content.next.version) + " - " if @content.next %>
     <%= link_to(l(:label_current_version), :action => 'show', :id => @page.title, :project_id => @page.project) %>
     <br />
     <em><%= @content.author ? link_to_user(@content.author) : l(:label_user_anonymous)