let app_file default to the file subclassing Sinatra::Base in modular apps

CHANGES

@@ -10,6 +10,9 @@
    explicitly to prevent that behavior. (Magnus Holm, Ryan Tomayko, Konstantin
    Haase)
 
+ * `settings.app_file` now defaults to the file subclassing `Sinatra::Base` in
+   modular applications. (Konstantin Haase)
+
  * Set up `Rack::Logger` or `Rack::NullLogger` depending on whether logging
    was enabled or not. Also, expose that logger with the `logger` helper
    method. (Konstantin Haase)

README.rdoc

@@ -1382,7 +1382,7 @@ different default settings:
 
   Setting             Classic                 Modular
 
-  app_file            file loading sinatra    nil
+  app_file            file loading sinatra    file subclassing Sinatra::Base
   run                 $0 == app_file          false
   logging             true                    false
   method_override     true                    false

lib/sinatra/base.rb

@@ -1310,6 +1310,7 @@ module Sinatra
 
       def inherited(subclass)
         subclass.reset!
+        subclass.set :app_file, caller_files.first unless subclass.app_file?
         super
       end
 
@@ -1471,6 +1472,7 @@ module Sinatra
     set :method_override, true
     set :run, Proc.new { ! test? }
     set :session_secret, Proc.new { super() unless development? }
+    set :app_file, nil
 
     def self.register(*extensions, &block) #:nodoc:
       added_methods = extensions.map {|m| m.public_instance_methods }.flatten

test/settings_test.rb

@@ -3,10 +3,10 @@ require File.dirname(__FILE__) + '/helper'
 class SettingsTest < Test::Unit::TestCase
   setup do
     @base = Sinatra.new(Sinatra::Base)
-    @base.set :environment, :foo
+    @base.set :environment => :foo, :app_file => nil
 
     @application = Sinatra.new(Sinatra::Application)
-    @application.set :environment, :foo
+    @application.set :environment => :foo, :app_file => nil
   end
 
   it 'sets settings to literal values' do
@@ -358,9 +358,13 @@ class SettingsTest < Test::Unit::TestCase
   end
 
   describe 'app_file' do
-    it 'is nil' do
-      assert_nil @base.app_file
-      assert_nil @application.app_file
+    it 'is nil for base classes' do
+      assert_nil Sinatra::Base.app_file
+      assert_nil Sinatra::Application.app_file
+    end
+
+    it 'defaults to the file subclassing' do
+      assert_equal __FILE__, Sinatra.new.app_file
     end
   end