Opposite filters (tags) with higher precedence cancel out those with …

…lower precedence

Beginning to address rspec#369 and rspec#327.

This commit deals with command line, ENV and file options, but does not
address options defined with RSpec.configure. Once that's addressed we
can close rspec#369 and rspec#327.

This does, implicitly, let --tag options set in rake tasks overwrite
those in option files.

lib/rspec/core/configuration_options.rb

@@ -24,7 +24,11 @@ def configure(config)
       end
 
       def parse_options
-        @options ||= [file_options, command_line_options, env_options].inject {|merged, o| merged.merge o}
+        @options ||= [*file_options, command_line_options, env_options].inject do |merged, pending|
+          resolve_opposite_filters(merged, pending, :inclusion_filter, :exclusion_filter)
+          resolve_opposite_filters(merged, pending, :exclusion_filter, :inclusion_filter)
+          merged.merge(pending)
+        end
       end
 
       def drb_argv
@@ -33,6 +37,16 @@ def drb_argv
 
     private
 
+      def resolve_opposite_filters(current,pending,filter,opposite_filter)
+        if current[filter] && pending[opposite_filter]
+          current[filter].each_pair do |key, value|
+            if pending[opposite_filter][key] == value
+              current[filter].delete(key)
+            end
+          end
+        end
+      end
+
       def order(keys, *ordered)
         ordered.reverse.each do |key|
           keys.unshift(key) if keys.delete(key)
@@ -41,7 +55,7 @@ def order(keys, *ordered)
       end
 
       def file_options
-        custom_options_file ? custom_options : global_options.merge(local_options)
+        custom_options_file ? [custom_options] : [global_options, local_options]
       end
 
       def env_options

lib/rspec/core/shared_example_group.rb

@@ -15,7 +15,6 @@ def shared_context(*args, &block)
             host.class_eval(&block)
           end
           RSpec.configuration.extend(mod, *args)
-        else
         end
       end
 

spec/rspec/core/configuration_options_spec.rb

@@ -289,6 +289,30 @@
       parse_options[:formatters].should eq([['local']])
     end
 
+    it "overwrites opposite tags according to precedence (inclusion overwrites exclusion)" do
+      File.open("./.rspec", "w") {|f| f << "--tag foo"}
+      File.open("~/.rspec", "w") {|f| f << "--tag ~foo"}
+      parsed = parse_options
+      parsed[:inclusion_filter].should eq(:foo => true)
+      parsed[:exclusion_filter].should be_empty
+    end
+
+    it "does not overwrite opposite tags with different values" do
+      File.open("./.rspec", "w") {|f| f << "--tag foo:baa"}
+      File.open("~/.rspec", "w") {|f| f << "--tag ~foo:brr"}
+      parsed = parse_options
+      parsed[:inclusion_filter].should eq(:foo => 'baa')
+      parsed[:exclusion_filter].should eq(:foo => 'brr')
+    end
+
+    it "overwrites opposite tags according to precedence (exclusion overwrites inclusion)" do
+      File.open("./.rspec", "w") {|f| f << "--tag ~foo"}
+      File.open("~/.rspec", "w") {|f| f << "--tag foo"}
+      parsed = parse_options
+      parsed[:inclusion_filter].should be_empty
+      parsed[:exclusion_filter].should eq(:foo => true)
+    end
+
     context "with custom options file" do
       it "ignores local and global options files" do
         File.open("./.rspec", "w") {|f| f << "--format local"}