Make force work in conditions for futures, not only promises.

lib/future.rb

@@ -27,7 +27,7 @@ def initialize(&block)
   # @return [Object]
   def __force__
     @thread.join if @thread
-    @promise
+    @promise.__force__
   end
   alias_method :force, :__force__
 

spec/promise_spec.rb

@@ -33,6 +33,18 @@
     expect {x = [ 1, @method.call { x / 0 }]}.to_not raise_error
   end
 
+  describe 'compatibility with Marshal' do
+    it 'should not respond_to? marshal_dump' do
+      x = @method.call { 3 + 5 }
+      expect(x).to_not respond_to(:marshal_dump)
+    end
+
+    it 'should respond_to? _dump' do
+      x = @method.call { 3 + 5 }
+      expect(x).to respond_to(:_dump)
+    end
+  end
+
   describe 'an object referencing a promise' do
     class ClassResulting
       attr_reader :value

spec/shared_promise.rb

@@ -21,6 +21,20 @@
     expect(x).to eq 8
   end
 
+  it "should work in conditions (at least when forced)" do
+    for value in [true, false, nil, 1, "test", [], {}, Object.new]
+      result = (value if value)
+      x = @method.call { value }
+      expect(x.__force__).to eq value
+      expect(x).to eq value
+      expect((value if x.__force__)).to eq result
+      # Unfortunately this can't be done:
+      # expect((value if x)).to eq result
+      # The promise/future itself is always not nil, so we get this instead:
+      expect((value if x)).to eq value
+    end
+  end
+
   it "should respond_to? force" do
     x = @method.call { 3 + 5 }
     expect(x).to respond_to(:force)
@@ -129,15 +143,4 @@
     expect(changeds.size).to eq 10
   end
 
-  describe 'compatibility with Marshal' do
-    it 'should not respond_to? marshal_dump' do
-      x = @method.call { 3 + 5 }
-      expect(x).to_not respond_to(:marshal_dump)
-    end
-
-    it 'should respond_to? _dump' do
-      x = @method.call { 3 + 5 }
-      expect(x).to respond_to(:_dump)
-    end
-  end
 end