feat: fallback ask to default when in non interactive run

CHANGELOG.md

@@ -19,6 +19,7 @@ gem "capistrano", github: "capistrano/capistrano", require: false
 [master]: https://github.com/capistrano/capistrano/compare/v3.10.2...HEAD
 
 * Your contribution here!
+* [#1972](https://github.com/capistrano/capistrano/pull/1972): fallback ask to default when used in non interactive session
 
 ## [`3.10.2`] (2018-04-15)
 

lib/capistrano/configuration/question.rb

@@ -36,6 +36,8 @@ module Capistrano
       end
 
       def gets
+        return unless $stdin.tty?
+
         if echo?
           $stdin.gets
         else

spec/lib/capistrano/configuration/question_spec.rb

@@ -57,6 +57,17 @@ module Capistrano
             expect(question.call).to eq(branch)
           end
         end
+
+        context "tty unavailable" do
+          before do
+            $stdin.expects(:gets).never
+            $stdin.expects(:tty?).returns(false)
+          end
+
+          it "returns the default as the value" do
+            expect(question.call).to eq(default)
+          end
+        end
       end
     end
   end