From 76c2bc27a891e4aefd64bea216541fc4dfa9c788 Mon Sep 17 00:00:00 2001
From: Christoph <christoph@mixxt.net>
Date: Wed, 23 Oct 2013 11:15:11 +0200
Subject: [PATCH] Improve fingerprints when error messages differ only in object memory addresses

---
 app/models/fingerprint.rb       |  8 +++++++-
 spec/models/fingerprint_spec.rb | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/app/models/fingerprint.rb b/app/models/fingerprint.rb
index f76a1b8..66001c5 100644
--- a/app/models/fingerprint.rb
+++ b/app/models/fingerprint.rb
@@ -29,7 +29,13 @@ class Fingerprint
   end
 
   def file_or_message
-    @file_or_message ||= notice.message + notice.backtrace.fingerprint
+    @file_or_message ||= unified_message + notice.backtrace.fingerprint
+  end
+
+  # filter memory addresses out of object strings
+  # example: "#<Object:0x007fa2b33d9458>" becomes "#<Object>"
+  def unified_message
+    notice.message.gsub(/(#<.+?):[0-9a-f]x[0-9a-f]+(>)/, '\1\2')
   end
 
 end
diff --git a/spec/models/fingerprint_spec.rb b/spec/models/fingerprint_spec.rb
index 1c47f3e..78db0a0 100644
--- a/spec/models/fingerprint_spec.rb
+++ b/spec/models/fingerprint_spec.rb
@@ -34,6 +34,53 @@ describe Fingerprint do
         ).not_to eql Fingerprint.generate(notice2, "api key")
       end
     end
+
+    context 'with messages differing in object string memory addresses' do
+      let(:backtrace_2) { backtrace }
+
+      before do
+        notice1.message = "NoMethodError: undefined method `foo' for #<ActiveSupport::HashWithIndifferentAccess:0x007f6bfe3287e8>"
+        notice2.message = "NoMethodError: undefined method `foo' for #<ActiveSupport::HashWithIndifferentAccess:0x007f6bfd9f5338>"
+      end
+
+      its 'fingerprints should be equal' do
+        Fingerprint.generate(notice1, 'api key').should eq Fingerprint.generate(notice2, 'api key')
+      end
+    end
+
+    context 'with different messages at same stacktrace' do
+      let(:backtrace_2) { backtrace }
+
+      before do
+        notice1.message = "NoMethodError: undefined method `bar' for #<ActiveSupport::HashWithIndifferentAccess:0x007f6bfe3287e8>"
+        notice2.message = "NoMethodError: undefined method `bar' for nil:NilClass"
+      end
+
+      its 'fingerprints should not be equal' do
+        Fingerprint.generate(notice1, 'api key').should_not eq Fingerprint.generate(notice2, 'api key')
+      end
+    end
+  end
+
+  describe '#unified_message' do
+    subject{ Fingerprint.new(double('notice', message: message), 'api key').unified_message }
+
+    context "full error message" do
+      let(:message) { "NoMethodError: undefined method `foo' for #<ActiveSupport::HashWithIndifferentAccess:0x007f6bfe3287e8>" }
+
+      it 'removes memory address from object strings' do
+        should eq "NoMethodError: undefined method `foo' for #<ActiveSupport::HashWithIndifferentAccess>"
+      end
+    end
+
+    context "multiple object strings in message" do
+      let(:message) { "#<ActiveSupport::HashWithIndifferentAccess:0x007f6bfe3287e8> #<Object:0x007fa2b33d9458>" }
+
+      it 'removes memory addresses globally' do
+        should eq "#<ActiveSupport::HashWithIndifferentAccess> #<Object>"
+      end
+    end
+
   end
 
 end
--
libgit2 0.21.2