detect being inside a rails application even from a subdirectory

Signed-off-by: David Heinemeier Hansson <david@loudthinking.com>

1 files changed, 28 insertions, 0 deletions

diff --git a/railties/lib/rails/script_rails_loader.rb b/railties/lib/rails/script_rails_loader.rb
new file mode 100644
index 0000000000..8fbd3bf492
--- /dev/null
+++ b/railties/lib/rails/script_rails_loader.rb
@@ -0,0 +1,28 @@
+require 'pathname'
+
+module Rails
+  module ScriptRailsLoader
+    RUBY = File.join(*RbConfig::CONFIG.values_at("bindir", "ruby_install_name")) + RbConfig::CONFIG["EXEEXT"]
+    SCRIPT_RAILS = File.join('script', 'rails')
+
+    def self.exec_script_rails!
+      cwd = Dir.pwd
+      exec RUBY, SCRIPT_RAILS, *ARGV if in_rails_application?
+      Dir.chdir("..") do
+        # Recurse in a chdir block: if the search fails we want to be sure
+        # the application is generated in the original working directory.
+        exec_script_rails! unless cwd == Dir.pwd
+      end
+    rescue SystemCallError
+      # could not chdir, no problem just return
+    end
+    
+    def self.in_rails_application?
+      File.exists?(SCRIPT_RAILS) || in_rails_application_subdirectory?
+    end
+    
+    def self.in_rails_application_subdirectory?(path = Pathname.new(Dir.pwd))
+      File.exists?(File.join(path, SCRIPT_RAILS)) || !path.root? && in_rails_application_subdirectory?(path.parent)
+    end
+  end
+end
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