Explicitly ignore :suite hooks from Hooks module.

The Configuration class now handles these and it’s
the only place they are supported.

This allows us to reduce object allocations a bit,
and also clarifies the semantics of :suite hooks.

Author: myronmarston

benchmarks/allocations/1000_groups_1_example.rb

@@ -15,23 +15,51 @@
 
                class_plus                 count
 ----------------------------------------  -----
-String                                    32000
-Array                                     14000
-RubyVM::Env                                9000
+String                                    26000
+Array                                     15000
 Hash                                       9000
+RubyVM::Env                                9000
 Proc                                       9000
 RSpec::Core::Hooks::HookCollection         6000
 Array<String>                              5000
 MatchData                                  3000
+Module                                     2000
+Array<Module>                              2000
 RSpec::Core::Example::ExecutionResult      2000
 Array<String,Fixnum>                       2000
+RSpec::Core::Hooks::HookCollections        1000
+RSpec::Core::Hooks::AroundHookCollection   1000
+RSpec::Core::Metadata::ExampleHash         1000
+RSpec::Core::Metadata::ExampleGroupHash    1000
+Class                                      1000
+Array<Hash>                                1000
+Array<RSpec::Core::Example>                1000
+RSpec::Core::Example                       1000
+
+
+After removing `:suite` support from `Hooks` module,
+it cut Array and RSpec::Core::Hooks::HookCollection
+allocations by 2000 each:
+
+               class_plus                 count
+----------------------------------------  -----
+String                                    26000
+Array                                     13000
+Hash                                       9000
+Proc                                       9000
+RubyVM::Env                                9000
+Array<String>                              5000
+RSpec::Core::Hooks::HookCollection         4000
+MatchData                                  3000
 Array<Module>                              2000
+Array<String,Fixnum>                       2000
 Module                                     2000
+RSpec::Core::Example::ExecutionResult      2000
+RSpec::Core::Metadata::ExampleGroupHash    1000
 Class                                      1000
 Array<Hash>                                1000
-RSpec::Core::Metadata::ExampleGroupHash    1000
+RSpec::Core::Hooks::AroundHookCollection   1000
+RSpec::Core::Hooks::HookCollections        1000
 RSpec::Core::Metadata::ExampleHash         1000
 RSpec::Core::Example                       1000
 Array<RSpec::Core::Example>                1000
-RSpec::Core::Hooks::AroundHookCollection   1000
-RSpec::Core::Hooks::HookCollections        1000

lib/rspec/core/hooks.rb

@@ -326,12 +326,8 @@ def hooks
         @hooks ||= HookCollections.new(
           self,
           :around => { :example => AroundHookCollection.new },
-          :before => { :example => HookCollection.new,
-                       :context => HookCollection.new,
-                       :suite => HookCollection.new },
-          :after  => { :example => HookCollection.new,
-                       :context => HookCollection.new,
-                       :suite => HookCollection.new }
+          :before => { :example => HookCollection.new, :context => HookCollection.new },
+          :after  => { :example => HookCollection.new, :context => HookCollection.new }
         )
       end
 
@@ -496,6 +492,15 @@ def around_example_hooks_for(example, initial_procsy=nil)
 
         def register(prepend_or_append, hook, *args, &block)
           scope, options = scope_and_options_from(*args)
+
+          if scope == :suite
+            RSpec.warn_with "`#{hook}(:suite)` hooks are only supported on " \
+                            "the RSpec configuration object. This " \
+                            "`#{hook}(:suite)` hook, defined on an example " \
+                            "group, will be ignored."
+            return
+          end
+
           self[hook][scope].__send__(prepend_or_append,
                                      HOOK_TYPES[hook][scope].new(block, options))
         end
@@ -509,7 +514,7 @@ def run(hook, scope, example_or_group, initial_procsy=nil)
           find_hook(hook, scope, example_or_group, initial_procsy).run
         end
 
-        SCOPES = [:example, :context, :suite]
+        SCOPES = [:example, :context]
 
         SCOPE_ALIASES = { :each => :example, :all => :context }
 
@@ -532,6 +537,7 @@ def process(host, globals, position, scope)
         end
 
         def scope_and_options_from(*args)
+          return :suite if args.first == :suite
           scope = extract_scope_from(args)
           meta  = Metadata.build_hash_from(args, :warn_about_example_group_filtering)
           return scope, meta
@@ -573,8 +579,6 @@ def find_hook(hook, scope, example_or_group, initial_procsy)
             before_example_hooks_for(example_or_group)
           when [:after, :example]
             after_example_hooks_for(example_or_group)
-          when [:before, :suite], [:after, :suite]
-            self[hook][:suite].with(example_or_group)
           end
         end
 

spec/rspec/core/suite_hooks_spec.rb

@@ -21,6 +21,20 @@ module RSpec::Core
             RSpec.configuration.with_suite_hooks { }
           }.to raise_error(ZeroDivisionError)
         end
+
+        context "defined on an example group" do
+          it "is ignored with a clear warning" do
+            sequence = []
+
+            expect {
+              RSpec.describe "Group" do
+                __send__(type, :suite) { sequence << :suite_hook }
+                example { sequence << :example }
+              end.run
+            }.to change { sequence }.to([:example]).
+              and output(a_string_including("#{type}(:suite)")).to_stderr
+          end
+        end
       end
     end