From 09ad84fb712a30dd4302b9daa03d11281ac7d169 Mon Sep 17 00:00:00 2001
From: Andrew Haines <andrew@haines.org.nz>
Date: Tue, 5 Mar 2013 22:28:03 +0000
Subject: [PATCH] Rescue specific NameErrors when inferring classes

The previous behavior swallowed genuine NameErrors (as opposed to
failure to find the inferred class), for example when the user has
not updated the decorator base class from Draper::Base.
---
 lib/draper/decoratable.rb       |  3 ++-
 lib/draper/decorator.rb         | 12 ++++++++----
 spec/draper/decoratable_spec.rb |  7 +++++++
 spec/draper/decorator_spec.rb   | 25 +++++++++++++++++++++----
 4 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/lib/draper/decoratable.rb b/lib/draper/decoratable.rb
index de74e39..f77111a 100644
--- a/lib/draper/decoratable.rb
+++ b/lib/draper/decoratable.rb
@@ -68,7 +68,8 @@ module Draper
         decorator_name = [(namespace && namespace.name), "#{prefix}Decorator"].compact.join("::")
 
         decorator_name.constantize
-      rescue NameError
+      rescue NameError => error
+        raise unless error.missing_name?(decorator_name)
         raise Draper::UninferrableDecoratorError.new(self)
       end
 
diff --git a/lib/draper/decorator.rb b/lib/draper/decorator.rb
index 793fcea..3341ef0 100755
--- a/lib/draper/decorator.rb
+++ b/lib/draper/decorator.rb
@@ -212,8 +212,10 @@ module Draper
 
     # @return [Class] the class created by {decorate_collection}.
     def self.collection_decorator_class(namespace=nil)
-      collection_decorator_name(namespace).constantize
-    rescue NameError
+      name = collection_decorator_name(namespace)
+      name.constantize
+    rescue NameError => error
+      raise if name && !error.missing_name?(name)
       Draper::CollectionDecorator
     end
 
@@ -225,8 +227,10 @@ module Draper
     end
 
     def self.inferred_source_class
-      source_name.constantize
-    rescue NameError
+      name = source_name
+      name.constantize
+    rescue NameError => error
+      raise if name && !error.missing_name?(name)
       raise Draper::UninferrableSourceError.new(self)
     end
 
diff --git a/spec/draper/decoratable_spec.rb b/spec/draper/decoratable_spec.rb
index 67d0730..ca8f635 100644
--- a/spec/draper/decoratable_spec.rb
+++ b/spec/draper/decoratable_spec.rb
@@ -179,6 +179,13 @@ module Draper
           expect{Model.decorator_class}.to raise_error UninferrableDecoratorError
         end
       end
+
+      context "when an unrelated NameError is thrown" do
+        it "re-raises that error" do
+          String.any_instance.stub(:constantize).and_return{Draper::Base}
+          expect{Product.decorator_class}.to raise_error NameError, /Draper::Base/
+        end
+      end
     end
 
   end
diff --git a/spec/draper/decorator_spec.rb b/spec/draper/decorator_spec.rb
index f44c063..9d0e346 100755
--- a/spec/draper/decorator_spec.rb
+++ b/spec/draper/decorator_spec.rb
@@ -154,6 +154,13 @@ module Draper
           Decorator.decorate_collection(source, with: nil, namespace: DecoratorNamespace)
         end
       end
+
+      context "when a NameError is thrown" do
+        it "re-raises that error" do
+          String.any_instance.stub(:constantize).and_return{Draper::DecoratedEnumerableProxy}
+          expect{ProductDecorator.decorate_collection([])}.to raise_error NameError, /Draper::DecoratedEnumerableProxy/
+        end
+      end
     end
 
     describe ".decorates" do
@@ -179,20 +186,23 @@ module Draper
     end
 
     describe ".source_class" do
+      protect_class ProductDecorator
+      protect_class Namespaced::ProductDecorator
+
       context "when not set by .decorates" do
-        it "raises an error for a so-named 'Decorator'" do
+        it "raises an UninferrableSourceError for a so-named 'Decorator'" do
           expect{Decorator.source_class}.to raise_error UninferrableSourceError
         end
 
-        it "raises an error for anonymous decorators" do
+        it "raises an UninferrableSourceError for anonymous decorators" do
           expect{Class.new(Decorator).source_class}.to raise_error UninferrableSourceError
         end
 
-        it "raises an error for a decorator without a model" do
+        it "raises an UninferrableSourceError for a decorator without a model" do
           expect{OtherDecorator.source_class}.to raise_error UninferrableSourceError
         end
 
-        it "raises an error for other naming conventions" do
+        it "raises an UninferrableSourceError for other naming conventions" do
           expect{ProductPresenter.source_class}.to raise_error UninferrableSourceError
         end
 
@@ -203,6 +213,13 @@ module Draper
         it "infers namespaced sources" do
           expect(Namespaced::ProductDecorator.source_class).to be Namespaced::Product
         end
+
+        context "when an unrelated NameError is thrown" do
+          it "re-raises that error" do
+            String.any_instance.stub(:constantize).and_return{SomethingThatDoesntExist}
+            expect{ProductDecorator.source_class}.to raise_error NameError, /SomethingThatDoesntExist/
+          end
+        end
       end
     end