Add additional helpful section for frozen objects

Augument runtime errors with additional information that explains why an object might be frozen, and how frozen resource properties are a good thing.

Fixes #3734, for [accepted RFC 55](https://github.com/chef/chef-rfc/pull/135).

1 files changed, 16 insertions, 0 deletions

diff --git a/lib/chef/formatters/error_inspectors/compile_error_inspector.rb b/lib/chef/formatters/error_inspectors/compile_error_inspector.rb
index d64d5e7b01..fe418ed485 100644
--- a/lib/chef/formatters/error_inspectors/compile_error_inspector.rb
+++ b/lib/chef/formatters/error_inspectors/compile_error_inspector.rb
@@ -44,6 +44,18 @@ class Chef
             error_description.section("Cookbook Trace:", traceback)
             error_description.section("Relevant File Content:", context)
           end
+
+          if exception_message_modifying_frozen?
+            msg = <<-MESSAGE
+            Chef calls the freeze method on certain ruby objects to prevent
+            pollution across multiple instances. Specifically, resource
+            properties have frozen default values to avoid modifying the
+            property for all instances of a resource. Try modifying the
+            particular instance variable or using an instance accessor instead.
+            MESSAGE
+
+            error_description.section("Additional information:", msg.gsub(/^ {6}/, ''))
+          end
         end
 
         def context
@@ -111,6 +123,10 @@ class Chef
             end
         end
 
+        def exception_message_modifying_frozen?
+          exception.message.include?("can't modify frozen")
+        end
+
       end
 
     end