From 293199601341dc7c7bfe866047afd9cd3fd69f7f Mon Sep 17 00:00:00 2001
From: Jon de Andres <jon@wuaki.tv>
Date: Tue, 30 Sep 2014 01:22:19 +0200
Subject: [PATCH] Support nested exceptions for Ruby 2.1. Fixes #118.

---
 lib/rollbar.rb                  | 47 +++++++++++++++++++++++++--------
 spec/requests/home_spec.rb      | 12 +++++----
 spec/rollbar_spec.rb            | 47 ++++++++++++++++++++++++++++++++-
 spec/support/cause_exception.rb |  1 +
 4 files changed, 90 insertions(+), 17 deletions(-)
 create mode 100644 spec/support/cause_exception.rb

diff --git a/lib/rollbar.rb b/lib/rollbar.rb
index b2d68c23..c2fea020 100644
--- a/lib/rollbar.rb
+++ b/lib/rollbar.rb
@@ -307,6 +307,37 @@ def exception_data(exception, force_level = nil)
 
       data[:level] = force_level if force_level
 
+      traces = trace_chain(exception)
+
+      if traces.size > 1
+        body = {
+          :trace_chain => traces
+        }
+      elsif traces.size == 1
+        body = {
+          :trace => traces[0]
+        }
+      end
+
+      data[:body] = body
+
+      data[:server] = server_data
+
+      data
+    end
+
+    def trace_chain(exception)
+      traces = [trace_data(exception)]
+
+      while exception.respond_to?(:cause) && (cause = exception.cause)
+        traces << trace_data(cause)
+        exception = cause
+      end
+
+      traces
+    end
+
+    def trace_data(exception)
       # parse backtrace
       if exception.backtrace.respond_to?( :map )
         frames = exception.backtrace.map { |frame|
@@ -324,19 +355,13 @@ def exception_data(exception, force_level = nil)
         frames = []
       end
 
-      data[:body] = {
-        :trace => {
-          :frames => frames,
-          :exception => {
-            :class => exception.class.name,
-            :message => exception.message
-          }
+      {
+        :frames => frames,
+        :exception => {
+          :class => exception.class.name,
+          :message => exception.message
         }
       }
-
-      data[:server] = server_data
-
-      data
     end
 
     def logger
diff --git a/spec/requests/home_spec.rb b/spec/requests/home_spec.rb
index 8528f344..8996d75e 100644
--- a/spec/requests/home_spec.rb
+++ b/spec/requests/home_spec.rb
@@ -22,7 +22,7 @@
         expect{ get 'current_user', nil, :cookie => '8%B' }.to raise_exception
 
         Rollbar.last_report.should_not be_nil
-  
+
         exception_info = Rollbar.last_report[:body][:trace][:exception]
         exception_info[:class].should == 'ArgumentError'
         exception_info[:message].should == 'invalid %-encoding (8%B)'
@@ -44,11 +44,13 @@
     end
 
     it "should report uncaught exceptions" do
-      expect{ get 'current_user' }.to raise_exception
+      expect { get 'current_user' }.to raise_exception
+
+      body = Rollbar.last_report[:body]
+      trace = body[:trace] && body[:trace] || body[:trace_chain][0]
 
-      exception_info = Rollbar.last_report[:body][:trace][:exception]
-      exception_info[:class].should == 'NoMethodError'
-      # exception_info[:message].should == 'undefined method `-\' for "1":String'
+      trace[:exception][:class].should == 'NoMethodError'
+      trace[:exception][:message].should == 'undefined method `-\' for "1":String'
     end
   end
 end
diff --git a/spec/rollbar_spec.rb b/spec/rollbar_spec.rb
index 0b120dfb..0df3dcb5 100644
--- a/spec/rollbar_spec.rb
+++ b/spec/rollbar_spec.rb
@@ -592,7 +592,7 @@ def backtrace
     end
   end
 
-  context 'exception_data' do
+  describe '.exception_data' do
     before(:each) do
       configure
       begin
@@ -647,6 +647,51 @@ def backtrace
       end
     end
 
+    context 'with nested exceptions' do
+      let(:crashing_code) do
+        proc do
+          begin
+            begin
+              fail CauseException.new('the cause')
+            rescue
+              fail StandardError.new('the error')
+            end
+          rescue => e
+            e
+          end
+        end
+      end
+      let(:rescued_exception) { crashing_code.call }
+
+      if Exception.instance_methods.include?(:cause)
+        it 'sends the two exceptions in the trace_chain attribute' do
+          data = Rollbar.send(:exception_data, rescued_exception)
+          body = data[:body]
+
+          body[:trace].should be_nil
+          body[:trace_chain].should be_kind_of(Array)
+
+          chain = body[:trace_chain]
+          chain[0][:exception][:class].should match(/StandardError/)
+          chain[0][:exception][:message].should match(/the error/)
+
+          chain[1][:exception][:class].should match(/CauseException/)
+          chain[1][:exception][:message].should match(/the cause/)
+        end
+
+      else
+        it 'sends only the last exception in the trace attribute' do
+          data = Rollbar.send(:exception_data, rescued_exception)
+          body = data[:body]
+
+          body[:trace].should be_kind_of(Hash)
+          body[:trace_chain].should be_nil
+
+          body[:trace][:exception][:class].should match(/StandardError/)
+          body[:trace][:exception][:message].should match(/the error/)
+        end
+      end
+    end
   end
 
   context 'logger' do
diff --git a/spec/support/cause_exception.rb b/spec/support/cause_exception.rb
new file mode 100644
index 00000000..0a79f583
--- /dev/null
+++ b/spec/support/cause_exception.rb
@@ -0,0 +1 @@
+class CauseException < StandardError; end