Improve judging errors on the submission page (#267)

This adds a proper error message and hides test cases on the
submission page when judging fails.

app/models/submission.rb

@@ -149,7 +149,7 @@ def update_test_messages
 
       judge_data = self.judge_data
       return if judge_data.status == :pending # incomplete judge_log
-      return if judge_data.errored? # judge errored - very bad
+      return if judge_data.data.has_key?('error') # judge errored - very bad
 
       errors = []
       warnings = []

app/models/submission/judge_data.rb

@@ -274,7 +274,7 @@ def initialize(log, test_sets, test_cases, prerequisite_sets = [])
     end
 
     def errored?
-      data.has_key?('error')
+      data.has_key?('error') || status == :error
     end
 
     def completed?

app/views/submissions/show.html.erb

@@ -5,7 +5,12 @@
 
 <%= stylesheet_link_tag "submission" %>
 
-<% if @submission.score == nil %>
+<% @judge_data = @submission.judge_data %>
+<% if @judge_data.errored? %>
+  <p>
+    <b>An unexpected error has occurred during judging. Please retry the submission, or contact us at <%= mail_to "[email protected]" %> if the error persists.</b>
+  </p>
+<% elsif @submission.score == nil %>
   <p>
     <b>This submission has not finished judging. Refresh this page in a minute or two to see the submission's score.</b>
   </p>
@@ -46,7 +51,6 @@
   <% end %>
 </p>
 
-<% @judge_data = @submission.judge_data %>
 <% if @judge_data.compiled? %>
   <table class="results">
     <tbody class="compilation status_<%= @judge_data.compilation.status %>">
@@ -76,7 +80,7 @@
   </table>
 <% end %>
 <table class="results">
-  <% if !@judge_data.compiled? || @judge_data.compilation.status == :success %>
+  <% if !@judge_data.errored? && (!@judge_data.compiled? || @judge_data.compilation.status == :success) %>
     <tbody class="headings">
       <th class="test_name"></th>
       <th>Time</th>

app/workers/judge_submission_worker.rb

@@ -46,7 +46,7 @@ def perform(submission_id)
   rescue StandardError => e
     unless self.submission.nil?
       submission.reload
-      submission.judge_log = {'error' => {'message' => e.message, 'backtrace' => e.backtrace}}.to_json
+      submission.judge_log = {'error' => {'message' => e.message, 'backtrace' => e.backtrace}, 'status' => 2}.to_json
       submission.save
     end
     raise