Exception handling for humans

Ability to pass exception_handler as a block to #render
and provide whatever behavior you want on handling exceptions

https://github.com/Shopify/liquid/pull/254

lib/liquid/context.rb

@@ -14,8 +14,7 @@ module Liquid
   #   context['bob']  #=> nil  class Context
   class Context
     attr_reader :scopes, :errors, :registers, :environments, :resource_limits
-
-    attr_accessor :rethrow_errors
+    attr_accessor :exception_handler
 
     SQUARE_BRACKETED = /\A\[(.*)\]\z/m
 
@@ -24,10 +23,13 @@ module Liquid
       @scopes          = [(outer_scope || {})]
       @registers       = registers
       @errors          = []
-      @rethrow_errors  = rethrow_errors
       @resource_limits = (resource_limits || {}).merge!({ :render_score_current => 0, :assign_score_current => 0 })
       squash_instance_assigns_with_environments
 
+      if rethrow_errors
+        self.exception_handler = ->(e) { true }
+      end
+
       @interrupts = []
       @filters = []
       @parsed_variables = Hash.new{ |cache, markup| cache[markup] = variable_parse(markup) } 
@@ -91,7 +93,8 @@ module Liquid
 
     def handle_error(e)
       errors.push(e)
-      raise if @rethrow_errors
+
+      raise if exception_handler && exception_handler.call(e)
 
       case e
       when SyntaxError
@@ -300,5 +303,4 @@ module Liquid
         end
       end # squash_instance_assigns_with_environments
   end # Context
-
 end # Liquid

lib/liquid/template.rb

@@ -142,7 +142,11 @@ module Liquid
       context = case args.first
       when Liquid::Context
         c = args.shift
-        c.rethrow_errors = true if @rethrow_errors
+
+        if @rethrow_errors
+          c.exception_handler = ->(e) { true }
+        end
+
         c
       when Liquid::Drop
         drop = args.shift
@@ -167,6 +171,9 @@ module Liquid
           context.add_filters(options[:filters])
         end
 
+        if options[:exception_handler]
+          context.exception_handler = options[:exception_handler]
+        end
       when Module
         context.add_filters(args.pop)
       when Array