1 files changed, 39 insertions, 4 deletions
diff --git a/lib/puppet/network/format_handler.rb b/lib/puppet/network/format_handler.rb
index f3c3380e1..efeea79e3 100644
--- a/lib/puppet/network/format_handler.rb
+++ b/lib/puppet/network/format_handler.rb
@@ -3,6 +3,33 @@ require 'puppet/network'
 require 'puppet/network/format'
 
 module Puppet::Network::FormatHandler
+    class FormatError < Puppet::Error; end
+
+    class FormatProtector
+        attr_reader :format
+
+        def protect(method, args)
+            begin
+                Puppet::Network::FormatHandler.format(format).send(method, *args)
+            rescue => details
+                direction = method.to_s.include?("intern") ? "from" : "to"
+                error = FormatError.new("Could not %s %s %s: %s" % [method, direction, format, details])
+                error.set_backtrace(details.backtrace)
+                raise error
+            end
+        end
+
+        def initialize(format)
+            @format = format
+        end
+
+        [:intern, :intern_multiple, :render, :render_multiple].each do |method|
+            define_method(method) do |*args|
+                protect(method, args)
+            end
+        end
+    end
+
     @formats = {}
     def self.create(*args, &block)
         instance = Puppet::Network::Format.new(*args)
@@ -35,21 +62,29 @@ module Puppet::Network::FormatHandler
         @formats.values.find { |format| format.mime == mimetype }
     end
 
+    # Use a delegator to make sure any exceptions generated by our formats are
+    # handled intelligently.
+    def self.protected_format(name)
+        @format_protectors ||= {}
+        @format_protectors[name] ||= FormatProtector.new(name)
+        @format_protectors[name]
+    end
+
     module ClassMethods
         def format_handler
             Puppet::Network::FormatHandler
         end
 
         def convert_from(format, data)
-            format_handler.format(format).intern(self, data)
+            format_handler.protected_format(format).intern(self, data)
         end
 
         def convert_from_multiple(format, data)
-            format_handler.format(format).intern_multiple(self, data)
+            format_handler.protected_format(format).intern_multiple(self, data)
         end
 
         def render_multiple(format, instances)
-            format_handler.format(format).render_multiple(instances)
+            format_handler.protected_format(format).render_multiple(instances)
         end
 
         def default_format
@@ -72,7 +107,7 @@ module Puppet::Network::FormatHandler
         def render(format = nil)
             format ||= self.class.default_format
 
-            Puppet::Network::FormatHandler.format(format).render(self)
+            Puppet::Network::FormatHandler.protected_format(format).render(self)
         end
 
         def support_format?(name)