From 00a8b79dd67db8eaa851bcfed4db6147b976db98 Mon Sep 17 00:00:00 2001
From: Troels Knak-Nielsen <troelskn@gmail.com>
Date: Thu, 14 Jul 2016 13:24:56 +0200
Subject: [PATCH] Print a warning if a task is skipped because of
 re-invocation. Resolves #1689

---
 CHANGELOG.md                    |  1 +
 lib/capistrano/dsl.rb           | 14 ++++++++++++--
 spec/lib/capistrano/dsl_spec.rb | 11 +++++++++++
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index be48e9e4..0da065eb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@ Reverse Chronological Order:
 
 https://github.com/capistrano/capistrano/compare/v3.5.0...HEAD
 
+  * Added warning about future deprecation of reinvocation behaviour (@troelskn)
   * Added a `doctor:servers` subtask that outputs a summary of servers, roles & properties (@irvingwashington)
   * Raise a better error when an ‘after’ hook isn’t found (@jdelStrother)
   * Restrict the uploaded git wrapper script permissions to 700 (@irvingwashington)
diff --git a/lib/capistrano/dsl.rb b/lib/capistrano/dsl.rb
index 22c77f23..f9f8bc9c 100644
--- a/lib/capistrano/dsl.rb
+++ b/lib/capistrano/dsl.rb
@@ -11,8 +11,18 @@ module Capistrano
     include Paths
     include Stages
 
-    def invoke(task, *args)
-      Rake::Task[task].invoke(*args)
+    def invoke(task_name, *args)
+      task = Rake::Task[task_name]
+      if task && task.already_invoked
+        file, line, = caller.first.split(":")
+        colors = SSHKit::Color.new($stderr)
+        $stderr.puts colors.colorize("Skipping task `#{task_name}'.", :yellow)
+        $stderr.puts "Capistrano tasks may only be invoked once. Since task `#{task}' was previously invoked, invoke(\"#{task_name}\") at #{file}:#{line} will be skipped."
+        $stderr.puts "If you really meant to run this task again, first call Rake::Task[\"#{task_name}\"].reenable"
+        $stderr.puts colors.colorize("THIS BEHAVIOR MAY CHANGE IN A FUTURE VERSION OF CAPISTRANO. Please join the conversation here if this affects you.", :red)
+        $stderr.puts colors.colorize("https://github.com/capistrano/capistrano/issues/1686", :red)
+      end
+      task.invoke(*args)
     end
 
     def t(key, options={})
diff --git a/spec/lib/capistrano/dsl_spec.rb b/spec/lib/capistrano/dsl_spec.rb
index 82d208d3..f7b44229 100644
--- a/spec/lib/capistrano/dsl_spec.rb
+++ b/spec/lib/capistrano/dsl_spec.rb
@@ -69,5 +69,16 @@ module Capistrano
         end
       end
     end
+
+    describe "#invoke" do
+      it "will print a message on stderr, when reinvoking task" do
+        Rake::Task.define_task("some_task")
+
+        dsl.invoke("some_task")
+        expect do
+          dsl.invoke("some_task")
+        end.to output(/.*Capistrano tasks may only be invoked once.*/).to_stderr
+      end
+    end
   end
 end