Retrieve source code for the entire stack trace

Provide the ability to extract the source code of the entire exception stack
trace, not just the frame raising the error. This improves debugging
capability of the error page, especially for framework-related errors.

actionpack/lib/action_dispatch/middleware/debug_exceptions.rb

@@ -38,9 +38,7 @@ def render_exception(env, exception)
         template = ActionView::Base.new([RESCUES_TEMPLATE_PATH],
           request: request,
           exception: wrapper.exception,
-          application_trace: wrapper.application_trace,
-          framework_trace: wrapper.framework_trace,
-          full_trace: wrapper.full_trace,
+          traces: traces_from_wrapper(wrapper),
           routes_inspector: routes_inspector(exception),
           source_extract: wrapper.source_extract,
           line_number: wrapper.line_number,
@@ -95,5 +93,36 @@ def routes_inspector(exception)
         ActionDispatch::Routing::RoutesInspector.new(@routes_app.routes.routes)
       end
     end
+
+    # Augment the exception traces by providing ids for all unique stack frame
+    def traces_from_wrapper(wrapper)
+      application_trace = wrapper.application_trace
+      framework_trace = wrapper.framework_trace
+      full_trace = wrapper.full_trace
+
+      if application_trace && framework_trace
+        id_counter = 0
+
+        application_trace = application_trace.map do |trace|
+          prev = id_counter
+          id_counter += 1
+          { id: prev, trace: trace }
+        end
+
+        framework_trace = framework_trace.map do |trace|
+          prev = id_counter
+          id_counter += 1
+          { id: prev, trace: trace }
+        end
+
+        full_trace = application_trace + framework_trace
+      end
+
+      {
+        "Application Trace" => application_trace,
+        "Framework Trace" => framework_trace,
+        "Full Trace" => full_trace
+      }
+    end
   end
 end

actionpack/lib/action_dispatch/middleware/exception_wrapper.rb

@@ -61,12 +61,15 @@ def self.status_code_for_exception(class_name)
     end
 
     def source_extract
-      if application_trace && trace = application_trace.first
-        file, line, _ = trace.split(":")
-        @file = file
-        @line_number = line.to_i
-        source_fragment(@file, @line_number)
-      end
+      exception.backtrace.map do |trace|
+        file, line = trace.split(":")
+        line_number = line.to_i
+        {
+          code: source_fragment(file, line_number),
+          file: file,
+          line_number: line_number
+        }
+      end if exception.backtrace
     end
 
     private
@@ -110,7 +113,7 @@ def source_fragment(path, line)
     def expand_backtrace
       @exception.backtrace.unshift(
         @exception.to_s.split("\n")
-      ).flatten! 
+      ).flatten!
     end
   end
 end

actionpack/lib/action_dispatch/middleware/templates/rescues/_source.erb

 <% if @source_extract %>
-<div class="source">
-<div class="info">
-  Extracted source (around line <strong>#<%= @line_number %></strong>):
-</div>
-<div class="data">
-  <table cellpadding="0" cellspacing="0" class="lines">
-      <tr>
-        <td>
-          <pre class="line_numbers">
-            <% @source_extract.keys.each do |line_number| %>
+  <% @source_extract.each_with_index do |extract_source, index| %>
+    <% if extract_source[:code] %>
+      <div class="source <%="hidden" if index != 0%>" id="frame-source-<%=index%>">
+        <div class="info">
+          Extracted source (around line <strong>#<%= extract_source[:line_number] %></strong>):
+        </div>
+        <div class="data">
+          <table cellpadding="0" cellspacing="0" class="lines">
+            <tr>
+              <td>
+                <pre class="line_numbers">
+                  <% extract_source[:code].keys.each do |line_number| %>
 <span><%= line_number -%></span>
-            <% end %>
-          </pre>
-        </td>
+                  <% end %>
+                </pre>
+              </td>
 <td width="100%">
 <pre>
-<% @source_extract.each do |line, source| -%><div class="line<%= " active" if line == @line_number -%>"><%= source -%></div><% end -%>
+<% extract_source[:code].each do |line, source| -%><div class="line<%= " active" if line == extract_source[:line_number] -%>"><%= source -%></div><% end -%>
 </pre>
 </td>
-    </tr>
-  </table>
-</div>
-</div>
+            </tr>
+          </table>
+        </div>
+      </div>
+    <% end %>
+  <% end %>
 <% end %>

actionpack/lib/action_dispatch/middleware/templates/rescues/_trace.html.erb

-<%
-   traces = { "Application Trace" => @application_trace,
-              "Framework Trace"   => @framework_trace,
-              "Full Trace"        => @full_trace }
-   names = traces.keys
-%>
+<% names = @traces.keys %>
 
 <p><code>Rails.root: <%= defined?(Rails) && Rails.respond_to?(:root) ? Rails.root : "unset" %></code></p>
 
@@ -16,9 +11,42 @@
     <a href="#" onclick="<%= hide.join %><%= show %>; return false;"><%= name %></a> <%= '|' unless names.last == name %>
   <% end %>
 
-  <% traces.each do |name, trace| %>
+  <% @traces.each do |name, trace| %>
     <div id="<%= name.gsub(/\s/, '-') %>" style="display: <%= (name == "Application Trace") ? 'block' : 'none' %>;">
-      <pre><code><%= trace.join "\n" %></code></pre>
+      <pre><code><% trace.each do |frame| %><a class="trace-frames" data-frame-id="<%= frame[:id] %>" href="#"><%= frame[:trace] %></a><br><% end %></code></pre>
     </div>
   <% end %>
+
+  <script type="text/javascript">
+    var traceFrames = document.getElementsByClassName('trace-frames');
+    var selectedFrame, currentSource = document.getElementById('frame-source-0');
+
+    // Add click listeners for all stack frames
+    for (var i = 0; i < traceFrames.length; i++) {
+      traceFrames[i].addEventListener('click', function(e) {
+        e.preventDefault();
+        var target = e.target;
+        var frame_id = target.dataset.frameId;
+
+        if (selectedFrame) {
+          selectedFrame.className = selectedFrame.className.replace("selected", "");
+        }
+
+        target.className += " selected";
+        selectedFrame = target;
+
+        // Change the extracted source code
+        changeSourceExtract(frame_id);
+      });
+
+      function changeSourceExtract(frame_id) {
+        var el = document.getElementById('frame-source-' + frame_id);
+        if (currentSource && el) {
+          currentSource.className += " hidden";
+          el.className = el.className.replace(" hidden", "");
+          currentSource = el;
+        }
+      }
+    }
+  </script>
 </div>

actionpack/lib/action_dispatch/middleware/templates/rescues/_trace.text.erb

-<%
-  traces = { "Application Trace" => @application_trace,
-             "Framework Trace"   => @framework_trace,
-             "Full Trace"        => @full_trace }
-%>
-
 Rails.root: <%= defined?(Rails) && Rails.respond_to?(:root) ? Rails.root : "unset" %>
 
-<% traces.each do |name, trace| %>
+<% @traces.each do |name, trace| %>
 <% if trace.any? %>
 <%= name %>
-<%= trace.join("\n") %>
+<%= trace.map(&:trace).join("\n") %>
 
 <% end %>
 <% end %>

actionpack/lib/action_dispatch/middleware/templates/rescues/layout.erb

@@ -116,9 +116,15 @@
       background-color: #FFCCCC;
     }
 
+    .hidden {
+      display: none;
+    }
+
     a { color: #980905; }
     a:visited { color: #666; }
+    a.trace-frames { color: #666; }
     a:hover { color: #C52F24; }
+    a.trace-frames.selected { color: #C52F24 }
 
     <%= yield :style %>
   </style>

actionpack/lib/action_dispatch/middleware/templates/rescues/template_error.html.erb

-<% @source_extract = @exception.source_extract(0, :html) %>
 <header>
   <h1>
     <%= @exception.original_exception.class.to_s %> in
@@ -12,29 +11,7 @@
   </p>
   <pre><code><%= h @exception.message %></code></pre>
 
-  <div class="source">
-    <div class="info">
-      <p>Extracted source (around line <strong>#<%= @exception.line_number %></strong>):</p>
-    </div>
-    <div class="data">
-    <table cellpadding="0" cellspacing="0" class="lines">
-      <tr>
-        <td>
-          <pre class="line_numbers">
-            <% @source_extract.keys.each do |line_number| %>
-<span><%= line_number -%></span>
-            <% end %>
-          </pre>
-        </td>
-<td width="100%">
-<pre>
-<% @source_extract.each do |line, source| -%><div class="line<%= " active" if line == @exception.line_number -%>"><%= source -%></div><% end -%>
-</pre>
-</td>
-    </tr>
-  </table>
-</div>
-</div>
+  <%= render template: "rescues/_source" %>
 
   <p><%= @exception.sub_template_message %></p>
 

actionpack/lib/action_dispatch/middleware/templates/rescues/template_error.text.erb

-<% @source_extract = @exception.source_extract(0, :html) %>
 <%= @exception.original_exception.class.to_s %> in <%= @request.parameters["controller"].camelize if @request.parameters["controller"] %>#<%= @request.parameters["action"] %>
 
 Showing <%= @exception.file_name %> where line #<%= @exception.line_number %> raised: