Support a danger local command

lib/danger.rb

@@ -1,7 +1,7 @@
 require "danger/version"
 require "danger/dangerfile"
 require "danger/environment_manager"
-require "danger/runner"
+require "danger/commands/runner"
 require "danger/init"
 require "danger/available_values"
 

lib/danger/ci_source/local_git_repo.rb

@@ -0,0 +1,43 @@
+# For more info see: https://github.com/schacon/ruby-git
+
+require 'git'
+require 'uri'
+
+module Danger
+  module CISource
+    class LocalGitRepo < CI
+
+      # Never validate, it's not useful in production
+      def self.validates?(env)
+        false
+      end
+
+      def initialize(env)
+
+        git = Git.open(".")
+        if git.remote("origin")
+          url = git.remote("origin").url
+          # deal with https://
+          if url.starts_with "https://github.com/"
+            self.repo_slug = url.replace("https://github.com/", "").replace(".git", '')
+
+          # deal with SSH origin
+          elsif url.starts_with "git@github.com:"
+            self.repo_slug = url.replace("git@github.com:", "").replace(".git", '')
+          end
+        end
+
+        logs = git.log.since('2 weeks ago')
+        # Look for something like
+        # "Merge pull request #38 from KrauseFx/funky_circles\n\nAdd support for GitHub compare URLs that don't conform
+        pr_merge = logs.detect { |log| (/Merge pull request #[0-9]* from/ =~ log.message) == 0 }
+        if pr_merge
+          # then pull out the 38, to_i
+          self.pull_request_id = pr_merge.replace("Merge pull request #", "").to_i
+          self.base_commit = pr_merge.parents.[0].sha
+          self.head_commit = pr_merge.parents.[1].sha
+        end
+      end
+    end
+  end
+end

lib/danger/commands/local.rb

@@ -0,0 +1,35 @@
+module Danger
+  class Local < Runner
+    self.description = 'Run the Dangerfile locally.'
+    self.command = 'local'
+
+    def initialize(argv)
+      @dangerfile_path = "Dangerfile" if File.exist? "Dangerfile"
+      super
+    end
+
+    def validate!
+      super
+      unless @dangerfile_path
+        help! "Could not find a Dangerfile."
+      end
+    end
+
+    def run
+      # The order of the following commands is *really* important
+      dm = Dangerfile.new
+      dm.env = EnvironmentManager.new(ENV)
+      dm.env.ci_source = 
+      dm.env.fill_environment_vars
+      dm.env.scm.diff_for_folder(".", dm.env.ci_source.base_commit, dm.env.ci_source.head_commit)
+      dm.parse Pathname.new(@dangerfile_path)
+
+      post_results(dm)
+    end
+
+    def post_results(dm)
+      gh = dm.env.request_source
+      gh.update_pull_request!(warnings: dm.warnings, errors: dm.errors, messages: dm.messages)
+    end
+  end
+end