From 01c9782fa2392729bea08409e348fe049857d9d6 Mon Sep 17 00:00:00 2001 From: Xavier Noria Date: Fri, 6 Dec 2013 19:13:51 +0100 Subject: better error message for constants autoloaded from anonymous modules [fixes #13204] load_missing_constant is a private method that basically plays the role of const_missing. This method has an error condition that is surprising: it raises if the class or module already has the missing constant. How is it possible that if the class of module has the constant Ruby has called const_missing in the first place? The answer is that the from_mod argument is self except for anonymous modules, because const_missing passes down Object in such case (see the comment in the source code of the patch for the rationale). But then, it is better to pass down Object *if Object is also missing the constant* and otherwise err with an informative message right away. --- activesupport/lib/active_support/dependencies.rb | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) (limited to 'activesupport/lib') diff --git a/activesupport/lib/active_support/dependencies.rb b/activesupport/lib/active_support/dependencies.rb index 19d4ff51d7..6be19771f5 100644 --- a/activesupport/lib/active_support/dependencies.rb +++ b/activesupport/lib/active_support/dependencies.rb @@ -176,14 +176,22 @@ module ActiveSupport #:nodoc: end def const_missing(const_name) - # The interpreter does not pass nesting information, and in the - # case of anonymous modules we cannot even make the trade-off of - # assuming their name reflects the nesting. Resort to Object as - # the only meaningful guess we can make. - from_mod = anonymous? ? ::Object : self + from_mod = anonymous? ? guess_for_anonymous(const_name) : self Dependencies.load_missing_constant(from_mod, const_name) end + # Dependencies assumes the name of the module reflects the nesting (unless + # it can be proven that is not the case), and the path to the file that + # defines the constant. Anonymous modules cannot follow these conventions + # and we assume therefore the user wants to refer to a top-level constant. + def guess_for_anonymous(const_name) + if Object.const_defined?(const_name) + raise NameError, "#{const_name} cannot be autoloaded from an anonymous class or module" + else + Object + end + end + def unloadable(const_desc = self) super(const_desc) end @@ -456,8 +464,6 @@ module ActiveSupport #:nodoc: raise ArgumentError, "A copy of #{from_mod} has been removed from the module tree but is still active!" end - raise NameError, "#{from_mod} is not missing constant #{const_name}!" if from_mod.const_defined?(const_name, false) - qualified_name = qualified_name_for from_mod, const_name path_suffix = qualified_name.underscore -- cgit v1.2.3