[expectations] Revert "Merge pull request rspec/rspec-expectations#1125…

… from pirj/prevent-block-matchers-from-being-used-with-value-expectation-target"

This reverts commit f5bf9d8264ffd786a66fe25c3bb1125c93b59d89.

---
This commit was imported from rspec/rspec-expectations@9423442.

rspec-expectations/Changelog.md

@@ -1,3 +1,10 @@
+### Development
+
+Bug Fixes:
+
+* Revert #1125 due to the change being incompatible with our semantic versioning
+  policy.
+
 ### 3.8.5 / 2019-10-02
 [Full Changelog](http://github.com/rspec/rspec-expectations/compare/v3.8.4...v3.8.5)
 
@@ -22,7 +29,7 @@ Bug Fixes:
 * Prevent composed `all` matchers from leaking into their siblings leading to duplicate
   failures. (Jamie English, #1086)
 * Prevent objects which change their hash on comparison from failing change checks.
-  (Phil Pirozhkov, #1100)
+  (Phil Pirozhkov, #1110)
 * Issue an `ArgumentError` rather than a `NoMethodError` when `be_an_instance_of` and
   `be_kind_of` matchers encounter objects not supporting those methods.
   (Taichi Ishitani, #1107)

rspec-expectations/lib/rspec/expectations/expectation_target.rb

@@ -33,16 +33,16 @@ def initialize(value)
       end
 
       # @private
-      def self.for(value, &block)
+      def self.for(value, block)
         if UndefinedValue.equal?(value)
-          unless block_given?
+          unless block
             raise ArgumentError, "You must pass either an argument or a block to `expect`."
           end
           BlockExpectationTarget.new(block)
-        elsif block_given?
+        elsif block
           raise ArgumentError, "You cannot pass both an argument and a block to `expect`."
         else
-          ValueExpectationTarget.new(value)
+          new(value)
         end
       end
 
@@ -90,40 +90,6 @@ def prevent_operator_matchers(verb)
       include InstanceMethods
     end
 
-    # @private
-    # Validates the provided matcher to ensure it supports block
-    # expectations, in order to avoid user confusion when they
-    # use a block thinking the expectation will be on the return
-    # value of the block rather than the block itself.
-    class ValueExpectationTarget < ExpectationTarget
-      def to(matcher=nil, message=nil, &block)
-        enforce_value_expectation(matcher)
-        super
-      end
-
-      def not_to(matcher=nil, message=nil, &block)
-        enforce_value_expectation(matcher)
-        super
-      end
-
-    private
-
-      def enforce_value_expectation(matcher)
-        return if supports_value_expectations?(matcher)
-
-        raise ExpectationNotMetError, "You must pass a block rather than an argument to `expect` to use the provided " \
-          "block expectation matcher (#{RSpec::Support::ObjectFormatter.format(matcher)})."
-      end
-
-      def supports_value_expectations?(matcher)
-        if matcher.respond_to?(:supports_value_expectations?)
-          matcher.supports_value_expectations?
-        else
-          true
-        end
-      end
-    end
-
     # @private
     # Validates the provided matcher to ensure it supports block
     # expectations, in order to avoid user confusion when they
@@ -152,11 +118,9 @@ def enforce_block_expectation(matcher)
       end
 
       def supports_block_expectations?(matcher)
-        if matcher.respond_to?(:supports_block_expectations?)
-          matcher.supports_block_expectations?
-        else
-          false
-        end
+        matcher.supports_block_expectations?
+      rescue NoMethodError
+        false
       end
     end
   end

rspec-expectations/lib/rspec/expectations/syntax.rb

@@ -70,7 +70,7 @@ def enable_expect(syntax_host=::RSpec::Matchers)
 
         syntax_host.module_exec do
           def expect(value=::RSpec::Expectations::ExpectationTarget::UndefinedValue, &block)
-            ::RSpec::Expectations::ExpectationTarget.for(value, &block)
+            ::RSpec::Expectations::ExpectationTarget.for(value, block)
           end
         end
       end

rspec-expectations/lib/rspec/matchers/built_in/base_matcher.rb

@@ -78,11 +78,6 @@ def supports_block_expectations?
           false
         end
 
-        # @private
-        def supports_value_expectations?
-          true
-        end
-
         # @api private
         def expects_call_stack_jump?
           false

rspec-expectations/lib/rspec/matchers/built_in/change.rb

@@ -77,11 +77,6 @@ def supports_block_expectations?
           true
         end
 
-        # @private
-        def supports_value_expectations?
-          false
-        end
-
       private
 
         def initialize(receiver=nil, message=nil, &block)
@@ -112,10 +107,12 @@ def raise_block_syntax_error
         end
 
         def positive_failure_reason
+          return "was not given a block" unless Proc === @event_proc
           "is still #{@actual_before_description}"
         end
 
         def negative_failure_reason
+          return "was not given a block" unless Proc === @event_proc
           "did change from #{@actual_before_description} " \
           "to #{description_of change_details.actual_after}"
         end
@@ -161,14 +158,10 @@ def supports_block_expectations?
           true
         end
 
-        # @private
-        def supports_value_expectations?
-          false
-        end
-
       private
 
         def failure_reason
+          return "was not given a block" unless Proc === @event_proc
           "was changed by #{description_of @change_details.actual_delta}"
         end
       end
@@ -197,6 +190,7 @@ def description
 
         # @private
         def failure_message
+          return not_given_a_block_failure unless Proc === @event_proc
           return before_value_failure      unless @matches_before
           return did_not_change_failure    unless @change_details.changed?
           after_value_failure
@@ -207,11 +201,6 @@ def supports_block_expectations?
           true
         end
 
-        # @private
-        def supports_value_expectations?
-          false
-        end
-
       private
 
         def perform_change(event_proc)
@@ -253,6 +242,11 @@ def did_change_failure
           "did change from #{@actual_before_description} " \
           "to #{description_of @change_details.actual_after}"
         end
+
+        def not_given_a_block_failure
+          "expected #{@change_details.value_representation} to have changed " \
+          "#{change_description}, but was not given a block"
+        end
       end
 
       # @api private
@@ -284,6 +278,7 @@ def does_not_match?(event_proc)
 
         # @private
         def failure_message_when_negated
+          return not_given_a_block_failure unless Proc === @event_proc
           return before_value_failure unless @matches_before
           did_change_failure
         end

rspec-expectations/lib/rspec/matchers/built_in/compound.rb

@@ -26,19 +26,11 @@ def description
           "#{matcher_1.description} #{conjunction} #{matcher_2.description}"
         end
 
-        # @api private
         def supports_block_expectations?
           matcher_supports_block_expectations?(matcher_1) &&
           matcher_supports_block_expectations?(matcher_2)
         end
 
-        # @api private
-        def supports_value_expectations?
-          matcher_supports_value_expectations?(matcher_1) &&
-          matcher_supports_value_expectations?(matcher_2)
-        end
-
-        # @api private
         def expects_call_stack_jump?
           NestedEvaluator.matcher_expects_call_stack_jump?(matcher_1) ||
           NestedEvaluator.matcher_expects_call_stack_jump?(matcher_2)
@@ -110,12 +102,6 @@ def matcher_supports_block_expectations?(matcher)
           false
         end
 
-        def matcher_supports_value_expectations?(matcher)
-          matcher.supports_value_expectations?
-        rescue NoMethodError
-          true
-        end
-
         def matcher_is_diffable?(matcher)
           matcher.diffable?
         rescue NoMethodError

rspec-expectations/lib/rspec/matchers/built_in/output.rb

@@ -94,25 +94,20 @@ def supports_block_expectations?
           true
         end
 
-        # @api private
-        # Indicates this matcher matches against a block only.
-        # @return [False]
-        def supports_value_expectations?
-          false
-        end
-
       private
 
         def captured?
           @actual.length > 0
         end
 
         def positive_failure_reason
+          return "was not a block" unless Proc === @block
           return "output #{actual_output_description}" if @expected
           "did not"
         end
 
         def negative_failure_reason
+          return "was not a block" unless Proc === @block
           "output #{actual_output_description}"
         end
 

rspec-expectations/lib/rspec/matchers/built_in/raise_error.rb

@@ -76,12 +76,6 @@ def supports_block_expectations?
           true
         end
 
-        # @private
-        def supports_value_expectations?
-          false
-        end
-
-        # @private
         def expects_call_stack_jump?
           true
         end
@@ -205,6 +199,7 @@ def format_backtrace(backtrace)
         end
 
         def given_error
+          return " but was not given a block" unless Proc === @given_proc
           return " but nothing was raised" unless @actual_error
 
           backtrace = format_backtrace(@actual_error.backtrace)

rspec-expectations/lib/rspec/matchers/built_in/throw_symbol.rb

@@ -88,23 +88,20 @@ def description
         end
 
         # @api private
+        # Indicates this matcher matches against a block.
+        # @return [True]
         def supports_block_expectations?
           true
         end
 
-        # @api private
-        def supports_value_expectations?
-          false
-        end
-
-        # @api private
         def expects_call_stack_jump?
           true
         end
 
       private
 
         def actual_result
+          return "but was not a block" unless Proc === @block
           "got #{caught}"
         end