Merge pull request #1178 from rspec/remove-cache-busters-part-2

Remove cache busters part 2

lib/rspec/core/configuration.rb

@@ -861,7 +861,7 @@ def setup_load_path_and_require(paths)
       # @private
       if RUBY_VERSION.to_f >= 1.9
         def safe_extend(mod, host)
-          host.extend(mod) unless (class << host; self; end) < mod
+          host.extend(mod) unless host.singleton_class < mod
         end
       else
         def safe_extend(mod, host)

lib/rspec/core/filter_manager.rb

@@ -110,14 +110,14 @@ def without_conditional_filters
       module BackwardCompatibility
         def merge(orig, opposite, *updates)
           _warn_deprecated_keys(updates.last)
-          super
         end
 
         def reverse_merge(orig, opposite, *updates)
           _warn_deprecated_keys(updates.last)
-          super
         end
 
+      private
+
         # Supports a use case that probably doesn't exist: overriding the
         # if/unless procs.
         def _warn_deprecated_keys(updates)
@@ -133,12 +133,13 @@ def _warn_deprecated_key(key, updates)
         end
       end
 
+      include BackwardCompatibility
+
       attr_reader :exclusions, :inclusions
 
       def initialize
         @exclusions = ExclusionFilterHash.new
         @inclusions = InclusionFilterHash.new
-        extend(BackwardCompatibility)
       end
 
       def add_location(file_path, line_numbers)
@@ -198,6 +199,7 @@ def unless_standalone(*args)
       end
 
       def merge(orig, opposite, *updates)
+        super
         orig.merge!(updates.last).each_key {|k| opposite.delete(k)}
       end
 
@@ -207,6 +209,7 @@ def replace(orig, opposite, *updates)
       end
 
       def reverse_merge(orig, opposite, *updates)
+        super
         updated = updates.last.merge(orig)
         opposite.each_pair {|k,v| updated.delete(k) if updated[k] == v}
         orig.replace(updated)

lib/rspec/core/shared_example_group.rb

@@ -77,10 +77,10 @@ def add_group(source, *args, &block)
 
           unless args.empty?
             mod = Module.new
-            (class << mod; self; end).send :define_method, :extended  do |host|
+            (class << mod; self; end).send :define_method, :included  do |host|
               host.class_eval(&block)
             end
-            RSpec.configuration.extend mod, *args
+            RSpec.configuration.include mod, *args
           end
         end
 

script/ignores

@@ -30,3 +30,45 @@ lib/rspec/core/shared_example_group.rb:        alias_method :shared_examples_for
 # The `alias_method` calls below happen when users define a named let.
 # It happens at spec definition time, not spec run time.
 lib/rspec/core/memoized_helpers.rb:            alias_method :subject, name
+
+# These `const_set` calls happen at spec definition time,
+# not at spec run time, so they are OK.
+lib/rspec/core/example_group.rb:      const_scope.const_set(name, group)
+lib/rspec/core/memoized_helpers.rb:              example_group.const_set(:NamedSubjectPreventSuper, self)
+lib/rspec/core/memoized_helpers.rb:          example_group.const_set(:LetDefinitions, mod)
+
+# These mentions of `extend` get executed at spec definition time
+# (unless the user changes their RSpec config at spec run time, but
+# there's no way to work around that).
+lib/rspec/core/configuration.rb:      def extend(mod, \*filters)
+lib/rspec/core/configuration.rb:        include_or_extend_modules << \[:extend, mod, Metadata.build_hash_from(filters)\]
+lib/rspec/core/configuration.rb:          host.extend(mod) unless host.singleton_class < mod
+lib/rspec/core/configuration.rb:          host.extend(mod) unless (class << host; self; end).included_modules.include?(mod)
+lib/rspec/core/configuration.rb:          extend RSpec::SharedContext
+lib/rspec/core/dsl.rb:extend RSpec::Core::DSL
+lib/rspec/core/example_group.rb:      extend  Hooks
+lib/rspec/core/example_group.rb:      extend SharedExampleGroup
+lib/rspec/core/memoized_helpers.rb:        mod.extend(ClassMethods)
+lib/rspec/core/shared_example_group.rb:extend RSpec::Core::SharedExampleGroup::TopLevelDSL
+
+# These uses of `extend` would be nice to get rid of, but our prior attempts
+# to convert the metadata hash to a composition-based design have created perf
+# regressions. These lines also only are only executed when an example or
+# example group is defined, so they shouldn't ever blow the method cache
+# at spec run time.
+lib/rspec/core/metadata.rb:          store(:example_group, {:example_group => parent_group_metadata\[:example_group\].extend(GroupMetadataHash)}.extend(GroupMetadataHash))
+lib/rspec/core/metadata.rb:          store(:example_group, {}.extend(GroupMetadataHash))
+lib/rspec/core/metadata.rb:        dup.extend(ExampleMetadataHash).configure_for_example(description, user_metadata)
+
+# This use of `extend` only happens on 1.8.7, when a shared example group
+# is defined (to provide the Proc#source_location method on the provided
+# block). It should only happen at spec definition time (unless users are
+# defining shared example groups at spec run time).
+lib/rspec/core/shared_example_group.rb:            block.extend Module.new {
+
+# This happens when an example group is defined, not at spec run time.
+lib/rspec/core/example_group.rb:        subclass = Class.new(parent)
+
+# This happens at file load time.
+lib/rspec/core/formatters/deprecation_formatter.rb:    DeprecationError = Class.new(StandardError)
+

script/list_method_cache_busters.sh

@@ -0,0 +1,23 @@
+#!/bin/bash
+# set -x
+
+# This list is from https://charlie.bz/blog/things-that-clear-rubys-method-cache
+
+IGNORE_FILE=/tmp/cache_busters_ignore
+COMMENT_LINE_RE="^(\w|\/)+\.rb: +#"
+
+cat script/ignores | grep -v "^$" | ruby -ne 'puts $_.split(/\s+###/)[0]' > $IGNORE_FILE
+
+egrep 'def [a-z]*\..*' -R lib | grep -v "def self" | grep -v -f $IGNORE_FILE | egrep -v "$COMMENT_LINE_RE"
+grep undef -R lib | grep -v -f $IGNORE_FILE | egrep -v "$COMMENT_LINE_RE"
+grep alias_method -R lib | grep -v -f $IGNORE_FILE | egrep -v "$COMMENT_LINE_RE"
+grep remove_method -R lib | grep -v -f $IGNORE_FILE | egrep -v "$COMMENT_LINE_RE"
+grep const_set -R lib | grep -v -f $IGNORE_FILE | egrep -v "$COMMENT_LINE_RE"
+grep remove_const -R lib | grep -v -f $IGNORE_FILE | egrep -v "$COMMENT_LINE_RE"
+egrep '\bextend\b' -R lib | grep -v -f $IGNORE_FILE | egrep -v "$COMMENT_LINE_RE"
+grep 'Class.new' -R lib | grep -v -f $IGNORE_FILE | egrep -v "$COMMENT_LINE_RE"
+grep private_constant -R lib | grep -v -f $IGNORE_FILE | egrep -v "$COMMENT_LINE_RE"
+grep public_constant -R lib | grep -v -f $IGNORE_FILE | egrep -v "$COMMENT_LINE_RE"
+grep "Marshal.load" -R lib | grep -v -f $IGNORE_FILE | egrep -v "$COMMENT_LINE_RE"
+grep "OpenStruct.new" -R lib | grep -v -f $IGNORE_FILE | egrep -v "$COMMENT_LINE_RE"
+

script/prevent_runtime_method_cache_busters

@@ -0,0 +1,15 @@
+#!/usr/bin/env ruby
+
+method_cache_busters = `script/list_method_cache_busters.sh`.split("\n").map(&:chomp)
+
+if method_cache_busters.any?
+  puts "=" * 80
+  puts "Found #{method_cache_busters.size} new constructs that bust the method cache."
+  puts "These should be eliminated or added to the `ignores` file."
+  puts
+  puts "For more information, see https://charlie.bz/blog/things-that-clear-rubys-method-cache"
+  puts
+  puts method_cache_busters.join("\n")
+  puts "=" * 80
+  exit(1)
+end

script/test_all

@@ -42,6 +42,8 @@ fi
 # https://github.com/carlhuda/bundler/issues/2382
 bundle exec bin/cucumber --strict
 
+script/prevent_runtime_method_cache_busters
+
 # Test against other RSpec gems.
 
 # Delete the directory for idempotency when running locally

spec/rspec/core/shared_example_group_spec.rb

@@ -72,12 +72,12 @@ module SharedExampleGroup
         end
 
         context "given a hash" do
-          it "delegates extend on configuration" do
+          it "delegates include on configuration" do
             implementation = Proc.new { def bar; 'bar'; end }
             define_shared_group(:foo => :bar, &implementation)
             a = RSpec.configuration.include_or_extend_modules.first
-            expect(a[0]).to eq(:extend)
-            expect(Class.new.extend(a[1]).new.bar).to eq('bar')
+            expect(a[0]).to eq(:include)
+            expect(Class.new.send(:include, a[1]).new.bar).to eq('bar')
             expect(a[2]).to eq(:foo => :bar)
           end
         end
@@ -89,12 +89,12 @@ module SharedExampleGroup
             expect(SharedExampleGroup.registry.shared_example_groups[group]["name"]).to eq implementation
           end
 
-          it "delegates extend on configuration" do
+          it "delegates include on configuration" do
             implementation = Proc.new { def bar; 'bar'; end }
             define_shared_group("name", :foo => :bar, &implementation)
             a = RSpec.configuration.include_or_extend_modules.first
-            expect(a[0]).to eq(:extend)
-            expect(Class.new.extend(a[1]).new.bar).to eq('bar')
+            expect(a[0]).to eq(:include)
+            expect(Class.new.send(:include, a[1]).new.bar).to eq('bar')
             expect(a[2]).to eq(:foo => :bar)
           end
         end