From 1adf2508bdc70f377fc88f8912e842d7bc399db5 Mon Sep 17 00:00:00 2001
From: Matt Brictson <matt@mattbrictson.com>
Date: Sat, 21 May 2016 11:55:57 -0700
Subject: [PATCH] Raise if a stage has an invalid name like "deploy"

---
 features/stage_failure.feature     |  9 +++++++++
 features/step_definitions/setup.rb |  4 ++++
 lib/capistrano/dsl/stages.rb       | 16 +++++++++++++++-
 lib/capistrano/i18n.rb             |  1 +
 spec/support/test_app.rb           |  6 ++++++
 5 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 features/stage_failure.feature

diff --git a/features/stage_failure.feature b/features/stage_failure.feature
new file mode 100644
index 00000000..9201f2b7
--- /dev/null
+++ b/features/stage_failure.feature
@@ -0,0 +1,9 @@
+Feature: Stage failure
+
+  Background:
+    Given a test app with the default configuration
+    And a stage file named deploy.rb
+
+  Scenario: Running a task
+    When I run cap "doctor"
+    Then the task fails
diff --git a/features/step_definitions/setup.rb b/features/step_definitions/setup.rb
index a733813d..e1b7e5a5 100644
--- a/features/step_definitions/setup.rb
+++ b/features/step_definitions/setup.rb
@@ -52,3 +52,7 @@ Given(/^a custom task to run in the event of a failure$/) do
   safely_remove_file(TestApp.shared_path.join("failed"))
   TestApp.copy_task_to_test_app("spec/support/tasks/failed.rake")
 end
+
+Given(/^a stage file named (.+)$/) do |filename|
+  TestApp.write_local_stage_file(filename)
+end
diff --git a/lib/capistrano/dsl/stages.rb b/lib/capistrano/dsl/stages.rb
index 57c9dcc9..18dd91c9 100644
--- a/lib/capistrano/dsl/stages.rb
+++ b/lib/capistrano/dsl/stages.rb
@@ -1,8 +1,13 @@
 module Capistrano
   module DSL
     module Stages
+      RESERVED_NAMES = %w(deploy doctor install).freeze
+      private_constant :RESERVED_NAMES
+
       def stages
-        Dir[stage_definitions].map { |f| File.basename(f, ".rb") }
+        names = Dir[stage_definitions].map { |f| File.basename(f, ".rb") }
+        assert_valid_stage_names(names)
+        names
       end
 
       def stage_definitions
@@ -12,6 +17,15 @@ module Capistrano
       def stage_set?
         !!fetch(:stage, false)
       end
+
+      private
+
+      def assert_valid_stage_names(names)
+        invalid = names.find { |n| RESERVED_NAMES.include?(n) }
+        return if invalid.nil?
+
+        raise t("error.invalid_stage_name", name: invalid, path: stage_config_path.join("#{invalid}.rb"))
+      end
     end
   end
 end
diff --git a/lib/capistrano/i18n.rb b/lib/capistrano/i18n.rb
index c18cef5f..eb0a7db5 100644
--- a/lib/capistrano/i18n.rb
+++ b/lib/capistrano/i18n.rb
@@ -24,6 +24,7 @@ en = {
     bye: "bye"
   },
   error: {
+    invalid_stage_name: '"%{name}" is a reserved word and cannot be used as a stage. Rename "%{path}" to something else.',
     user: {
       does_not_exist: "User %{user} does not exists",
       cannot_switch: "Cannot switch to user %{user}"
diff --git a/spec/support/test_app.rb b/spec/support/test_app.rb
index ef0acbc6..299fe501 100644
--- a/spec/support/test_app.rb
+++ b/spec/support/test_app.rb
@@ -61,6 +61,12 @@ module TestApp
     end
   end
 
+  def write_local_stage_file(filename, config=nil)
+    File.open(test_app_path.join("config/deploy/#{filename}"), "w") do |file|
+      file.write(config) if config
+    end
+  end
+
   def append_to_deploy_file(config)
     File.open(test_stage_path, "a") do |file|
       file.write config + "\n"