any_instance_of stubs failing with class hierarchies

[etiennebarrie]

We’re seeing issues with the way any_instance_of stubs are reset.

These stubs apparently work by using on method_missing on the class, but the code (RR::Injections::MethodMissingInjection#reset line 44 called from RR::Space#reset_method_missing_injection) seems to be trying to remove method_missing even when it’s not defined on the subject class, but only on its parent class. RR::Injections::Injection#subject_has_method_defined? checks for all methods, even inherited ones, which then makes it fail when trying to remove the method.

Included is a failing spec showing the issue as a user of the lib. We also have a workaround that first orders the injections by @subject_class.ancestors.size before resetting them, which ensures that the parent classes’ method_missings are removed before those in inherited classes but it’s super ugly, so I’d rather not push that.

[mcmire]

This is what I'm getting using my fork:

$ ruby -I ~/code/github/forks/rr/lib -S rspec -b /tmp/rr-test.rb

with a class hierarchy
  stubs methods (FAILED - 1)

Failures:

  1) with a class hierarchy stubs methods
     Failure/Error: subject.to_s.should_not == "Subject is stubbed"
     NoMethodError:
       undefined method `dispatch_method' for nil:NilClass
     # /tmp/rr-test.rb:32:in `block (2 levels) in <top (required)>'
     # /Users/elliot/.rbenv/versions/1.9.3-p194-falcon/lib/ruby/gems/1.9.1/gems/rspec-core-2.12.2/lib/rspec/core/example.rb:114:in `instance_eval'
     # /Users/elliot/.rbenv/versions/1.9.3-p194-falcon/lib/ruby/gems/1.9.1/gems/rspec-core-2.12.2/lib/rspec/core/example.rb:114:in `block in run'
     # /Users/elliot/.rbenv/versions/1.9.3-p194-falcon/lib/ruby/gems/1.9.1/gems/rspec-core-2.12.2/lib/rspec/core/example.rb:254:in `with_around_each_hooks'
     # /Users/elliot/.rbenv/versions/1.9.3-p194-falcon/lib/ruby/gems/1.9.1/gems/rspec-core-2.12.2/lib/rspec/core/example.rb:111:in `run'
     # /Users/elliot/.rbenv/versions/1.9.3-p194-falcon/lib/ruby/gems/1.9.1/gems/rspec-core-2.12.2/lib/rspec/core/example_group.rb:388:in `block in run_examples'
     # /Users/elliot/.rbenv/versions/1.9.3-p194-falcon/lib/ruby/gems/1.9.1/gems/rspec-core-2.12.2/lib/rspec/core/example_group.rb:384:in `map'
     # /Users/elliot/.rbenv/versions/1.9.3-p194-falcon/lib/ruby/gems/1.9.1/gems/rspec-core-2.12.2/lib/rspec/core/example_group.rb:384:in `run_examples'
     # /Users/elliot/.rbenv/versions/1.9.3-p194-falcon/lib/ruby/gems/1.9.1/gems/rspec-core-2.12.2/lib/rspec/core/example_group.rb:369:in `run'
     # /Users/elliot/.rbenv/versions/1.9.3-p194-falcon/lib/ruby/gems/1.9.1/gems/rspec-core-2.12.2/lib/rspec/core/command_line.rb:28:in `block (2 levels) in run'
     # /Users/elliot/.rbenv/versions/1.9.3-p194-falcon/lib/ruby/gems/1.9.1/gems/rspec-core-2.12.2/lib/rspec/core/command_line.rb:28:in `map'
     # /Users/elliot/.rbenv/versions/1.9.3-p194-falcon/lib/ruby/gems/1.9.1/gems/rspec-core-2.12.2/lib/rspec/core/command_line.rb:28:in `block in run'
     # /Users/elliot/.rbenv/versions/1.9.3-p194-falcon/lib/ruby/gems/1.9.1/gems/rspec-core-2.12.2/lib/rspec/core/reporter.rb:34:in `report'
     # /Users/elliot/.rbenv/versions/1.9.3-p194-falcon/lib/ruby/gems/1.9.1/gems/rspec-core-2.12.2/lib/rspec/core/command_line.rb:25:in `run'
     # /Users/elliot/.rbenv/versions/1.9.3-p194-falcon/lib/ruby/gems/1.9.1/gems/rspec-core-2.12.2/lib/rspec/core/runner.rb:80:in `run'
     # /Users/elliot/.rbenv/versions/1.9.3-p194-falcon/lib/ruby/gems/1.9.1/gems/rspec-core-2.12.2/lib/rspec/core/runner.rb:17:in `block in autorun'

Finished in 0.00229 seconds
1 example, 1 failure

Failed examples:

rspec /tmp/rr-test.rb:20 # with a class hierarchy stubs methods

using this test file:

require 'rr'

require 'rspec/core'
require 'rspec/expectations'
RSpec.configure do |c|
  c.mock_with :nothing
end

class ParentClass; end
class SubjectClass < ParentClass; end

describe "with a class hierarchy" do
  include RR::Adapters::RSpec2

  before :each do
    any_instance_of(ParentClass, :to_s => "Subject is stubbed")
    any_instance_of(ParentClass, :foobar => lambda {:baz})
  end

  it "stubs methods" do
    any_instance_of(SubjectClass, :to_s => "Subject is stubbed")

    subject = SubjectClass.new
    subject.should_not respond_to(:baz)

    ParentClass.new.to_s.should == "Subject is stubbed"
    subject.to_s.should == "Subject is stubbed"
    subject.foobar.should == :baz

    RR.reset

    subject.to_s.should_not == "Subject is stubbed"
    subject.should_not respond_to(:baz)
  end
end