Don't silently ignore arbitrary method expectations when combining them with 'and_call_original' #382

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merged 3 commits into from Oct 5, 2013

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JonRowe commented Jul 28, 2013

I had a discussion with @myronmarston about a problem I ran into during the conversion of our RSpec suite to the new expect/allow syntax. The gist of it can be found here.

Funnily what I thought was a bug, never quite worked the way I thought it was and I refactored the spec after reading his suggestions. Myron asked me to also add an issue for it, though. So here we go :-)

The spec we talked about had used the following expectation.

CachedUser.should_receive(:where) do |args|
    expect(args[:id]).to have(3).items
    expect(contact_ids).to include(*args[:id])
end.and_call_original

The values passed to 'where' are sort of random so you can't really setup an argument matcher with 'with'. That's why we tried to verify them in the block. The whole code under test there was also part of an AREL call comparable to this one. That's where the 'and_call_original' came into the game

CachedUser.where(id: random_related_user_ids).all

The spec passed. Though, as Myron pointed out, 'and_call_original' completely replaces the block expectation, resulting in the inner expectations never to be executed.

That was a bit surprising to find out, but to be honest also a fault on my side, since I probably never saw the expectation fail in the first place :-/

To make that behavior more obvious I think it would be good to either raise an exception or to output a warning in that case.

Coverage Status

Coverage decreased (-0%) when pulling c05a378 on warn_when_overriding_implementation into 9202615 on master.

BjRo commented Jul 28, 2013

Awesome, thx!

@myronmarston myronmarston and 2 others commented on an outdated diff Jul 31, 2013

lib/rspec/mocks/warning.rb
+ def warning(text, options={})
+ warn_with "WARNING: #{text}.", options
+ end
+
+ def warn_with(message, options = {})
+ line = caller.find { |line| line !~ %r{/lib/rspec/(core|mocks|expectations|matchers|rails)/} }
+ message << " Use #{options[:replacement]} instead." if options[:replacement]
+ message << " Called from #{line}."
+ ::Kernel.warn message
+ end
+ end
+ end
+
+ extend(Mocks::Warning) unless respond_to?(:warning) && respond_to?(:warn_with)
+end
+
@myronmarston

myronmarston Jul 31, 2013

Owner

This file is really small and seems to have a lot in common with lib/rspec/mocks/deprecation.rb. Given that ruby (particularly 1.9) has had well-known perf problems with requires, I think it behooves us to not split things into so many small files. What do you think about combining these into one file?

@myronmarston

myronmarston Jul 31, 2013

Owner

Also, do you think this kind of warning should be printed in the deprecation stream or always to STDERR?

@JonRowe

JonRowe Jul 31, 2013

Owner

I've taken care of this in the other PR, and I will rebase off that when we've worked it into something we want to use :)

@xaviershay

xaviershay Oct 1, 2013

Member

@JonRowe which other PR? Has it been merged yet and can we move forward with this fix?

@JonRowe

JonRowe Oct 1, 2013

Owner

Really wishing I had noted the number...

@JonRowe

JonRowe Oct 2, 2013

Owner

Ah hah! Yes that makes sense :)

@myronmarston myronmarston commented on an outdated diff Jul 31, 2013

spec/rspec/mocks/and_call_original_spec.rb
@@ -22,24 +22,30 @@ def self.new_instance
let(:instance) { klass.new }
it 'passes the received message through to the original method' do
- instance.should_receive(:meth_1).and_call_original
+ allow(instance).to receive(:meth_1).and_call_original
@myronmarston

myronmarston Jul 31, 2013

Owner

Why did you change this from a message expectation to a stub? IMO, and_call_original doesn't really make sense with a stub, given that the and_call_original is only possible on a partial mock, and it would call the original normally anyway....

@myronmarston myronmarston commented on an outdated diff Jul 31, 2013

spec/rspec/mocks/and_call_original_spec.rb
expect(instance.meth_1).to eq(:original)
end
it 'passes args and blocks through to the original method' do
- instance.should_receive(:meth_2).and_call_original
+ allow(instance).to receive(:meth_2).and_call_original
@myronmarston

myronmarston Jul 31, 2013

Owner

Same here: why the change from a mock expectation?

@myronmarston myronmarston commented on an outdated diff Jul 31, 2013

lib/rspec/mocks/message_expectation.rb
@@ -116,6 +116,9 @@ def and_call_original
if @method_double.object.is_a?(RSpec::Mocks::TestDouble)
@error_generator.raise_only_valid_on_a_partial_mock(:and_call_original)
else
+ if implementation.inner_action
@myronmarston

myronmarston Jul 31, 2013

Owner

I think implementation.has_inner_action? would make more sense...thoughts?

@myronmarston myronmarston commented on the diff Jul 31, 2013

lib/rspec/mocks/message_expectation.rb
@@ -464,6 +467,7 @@ def initial_implementation_action=(action)
end
def inner_implementation_action=(action)
+ RSpec.warning("You're overriding a previous implementation for this stub") if implementation.inner_action
@myronmarston

myronmarston Jul 31, 2013

Owner

I think RSpec.warn reads better (as its a verb) than RSpec.warning (as warning is a noun). Thoughts?

@JonRowe

JonRowe Oct 2, 2013

Owner

This matches up with the stuff in rspec/rspec-core#1024, happy to have that discussion there :)

@myronmarston myronmarston commented on an outdated diff Jul 31, 2013

lib/rspec/mocks/message_expectation.rb
@@ -116,6 +116,9 @@ def and_call_original
if @method_double.object.is_a?(RSpec::Mocks::TestDouble)
@error_generator.raise_only_valid_on_a_partial_mock(:and_call_original)
else
+ if implementation.inner_action
+ RSpec.warning("You're overriding a previous implementation for this stub")
@myronmarston

myronmarston Jul 31, 2013

Owner

I think the "for this stub" language could be a bit confusing when it's a mock expectation and not a stub. Not sure if there's a more generic way to phrase it, though...

Owner

myronmarston commented Jul 31, 2013

In @BjRo's gist, it also came up that an expression like this:

      expect(CachedUser).to receive(:where) do |args|
        expect(args[:id]).to have(3).items
        expect(contact_ids).to include(*args[:id])
      end.and_call_original

...raises a confusing error (NoMethodError: undefined method 'and_call_original' for []:Array). It would be good to fix that as well.

Coverage Status

Changes Unknown when pulling d8bca94 on warn_when_overriding_implementation into * on master*.

Coverage Status

Changes Unknown when pulling 650bee8 on warn_when_overriding_implementation into * on master*.

Coverage Status

Changes Unknown when pulling 650bee8 on warn_when_overriding_implementation into * on master*.

Owner

JonRowe commented Oct 2, 2013

Ready for a review I guess.

@xaviershay xaviershay and 1 other commented on an outdated diff Oct 5, 2013

lib/rspec/mocks/warnings.rb
@@ -0,0 +1,31 @@
+module RSpec
+
+ unless respond_to?(:deprecate)
@xaviershay

xaviershay Oct 5, 2013

Member

Where else would this be defined? Comment required.

@JonRowe

JonRowe Oct 5, 2013

Owner

This whole file is for when the gems are used individually.

@xaviershay

xaviershay Oct 5, 2013

Member

Otherwise it picks up the one from rspec-core. I get it, think it's unusual enough to deserve a comment.

@JonRowe

JonRowe Oct 5, 2013

Owner

Yep I was already writing one ;)

Member

xaviershay commented Oct 5, 2013

Could final commit be squashed into another?

Member

xaviershay commented Oct 5, 2013

Looks good otherwise when build is green.

Owner

JonRowe commented Oct 5, 2013

It's awaiting rspec/rspec-core#1024 (to sync the warning stuff)

Coverage Status

Changes Unknown when pulling 894dd8b on warn_when_overriding_implementation into * on master*.

Owner

JonRowe commented Oct 5, 2013

Actually I think we can merge this now and sync up the warnings stuff later if need be

@xaviershay xaviershay commented on the diff Oct 5, 2013

lib/rspec/mocks/warnings.rb
@@ -0,0 +1,37 @@
+module RSpec
+
+ # We don't redefine the deprecation helpers
+ # when they already exist (defined by rspec-core etc)
Member

xaviershay commented Oct 5, 2013

Yeah I don't see a reason to gate this on the core PR. Worst case scenario we just need to come back here and change it again if core PR changes, that's not terrible.

Coverage Status

Changes Unknown when pulling 659b039 on warn_when_overriding_implementation into * on master*.

@JonRowe JonRowe added a commit that referenced this pull request Oct 5, 2013

@JonRowe JonRowe Merge pull request #382 from rspec/warn_when_overriding_implementation
Don't silently ignore arbitrary method expectations when combining them with 'and_call_original'
f434af5

@JonRowe JonRowe merged commit f434af5 into master Oct 5, 2013

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JonRowe deleted the warn_when_overriding_implementation branch Oct 5, 2013

Owner

myronmarston commented Oct 5, 2013

This looks good, but did we address the other odd error (NoMethodError: undefined method 'and_call_original' for []:Array) I mentioned above ?

Owner

JonRowe commented Oct 5, 2013

Hmm, no, but thats a block capture issue... e.g.

expect(user).to receive(:where) do |args|
  expect(args[:id].size).to eq 3
end.and_call_original

produces the weird error

expect(user).to( receive(:where) do |args|
  expect(args[:id].size).to eq 3
end.and_call_original )

Works fine.

Owner

myronmarston commented Oct 5, 2013

Ah...I know what's going on: that expression passes the block to to due to ruby's precedence rules. So and_call_original is being called from the return value of to. which is the return value of handle_matcher, which returns whatever matcher.matches? returns, which, in this case, is returning @recorded_customizations, which is an array:

https://github.com/rspec/rspec-mocks/blob/f434af58f87937aa09c44b4f50719aaa836bf6b0/lib/rspec/mocks/matchers/receive.rb#L76-L78

So, I think if we changed RSpec::Mocks::Matchers::Recive#setup_method_substitute to return expectation, it would allow further chaining. Want to take a stab at writing a failing spec, adding that, and seeing if it passes?

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