Prevent duplicate tags

Author: bootstraponline

Gemfile

@@ -1,4 +1,2 @@
 source 'https://rubygems.org'
-gemspec
-
-gem 'yard'
+gemspec

Rakefile

@@ -1,7 +1,9 @@
 # encoding: utf-8
+# ruby_lib Rakefile
 require 'rubygems'
 require 'rake'
 require 'date'
+require 'posix/spawn'
 
 # Defines gem name.
 def repo_name; 'appium_lib' end # ruby_lib published as appium_lib
@@ -63,6 +65,11 @@ task :dev do
   sh 'gem install --no-rdoc --no-ri redcarpet'
 end
 
+def tag_exists tag_name
+  cmd = %Q(git branch -a --contains "#{tag_name}")
+  POSIX::Spawn::Child.new(cmd).out.include? '* master'
+end
+
 # Inspired by Gollum's Rakefile
 desc 'Build and release a new gem to rubygems.org'
 task :release => :gem do
@@ -71,16 +78,20 @@ task :release => :gem do
     exit!
   end
 
+  # Commit then pull before pushing.
+  tag_name = "v#{version}"
+  raise 'Tag already exists!' if tag_exists tag_name
+
   # Commit then pull before pushing.
   sh "git commit --allow-empty -am 'Release #{version}'"
   sh 'git pull'
-  sh "git tag v#{version}"
-  # update notes and docs now that there's a new tag
+  sh "git tag #{tag_name}"
+  # update notes now that there's a new tag
   Rake::Task['notes'].execute
   Rake::Task['docs'].execute
   sh "git commit --allow-empty -am 'Update release notes'"
   sh 'git push origin master'
-  sh "git push origin v#{version}"
+  sh "git push origin #{tag_name}"
   sh "gem push #{repo_name}-#{version}.gem"
 end
 

appium_lib.gemspec

@@ -30,6 +30,8 @@ Gem::Specification.new do |s|
   s.add_runtime_dependency 'toml', '~> 0.0.4'
 
   s.add_development_dependency 'rake', '~> 10.0.4'
+  s.add_development_dependency 'yard', '~> 0.8.7.3'
+  s.add_development_dependency 'posix/spawn', '~> 0.3.6'
 
   s.files = `git ls-files`.split "\n"
 end