From ac7f5157ac9d35b40da74ad932e9997f3f3e38a4 Mon Sep 17 00:00:00 2001
From: tenderlove <tenderlove@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Tue, 6 Nov 2012 11:42:24 +0000
Subject: [PATCH] * object.c (rb_mod_const_get): Fix constant missing exception
 class   and message to maintain backwards compatibility. Constant search  
 should start at Object when constant starts with '::'

* test/ruby/test_module.rb: test for fixes

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@37494 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 ChangeLog                |  8 ++++++++
 object.c                 | 18 +++++++++++++++++-
 test/ruby/test_module.rb | 18 ++++++++++++++++++
 3 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/ChangeLog b/ChangeLog
index 0ff497f976..596f970955 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+Tue Nov  6 20:40:28 2012  Aaron Patterson <aaron@tenderlovemaking.com>
+
+	* object.c (rb_mod_const_get): Fix constant missing exception class
+	  and message to maintain backwards compatibility. Constant search
+	  should start at Object when constant starts with '::'
+
+	* test/ruby/test_module.rb: test for fixes
+
 Tue Nov  6 16:50:00 2012  Masaki Matsushita  <glass.saga@gmail.com>
 
 	* lib/tempfile.rb (Tempfile#inspect): fix confusing #inspect.
diff --git a/object.c b/object.c
index 1b020beaa3..89706dd9e7 100644
--- a/object.c
+++ b/object.c
@@ -1935,12 +1935,28 @@ rb_mod_const_get(int argc, VALUE *argv, VALUE mod)
     }
 
     pbeg = p = path;
+
+    if (!*p) {
+	rb_raise(rb_eNameError, "wrong constant name %s", path);
+    }
+
+    if (p[0] == ':' && p[1] == ':') {
+	mod = rb_cObject;
+	p += 2;
+	pbeg = p;
+    }
+
     while (*p) {
 	while (*p && *p != ':') p++;
+
+	if (pbeg == p) {
+	    rb_raise(rb_eNameError, "wrong constant name %s", path);
+	}
+
 	id = rb_intern3(pbeg, p-pbeg, enc);
 	if (p[0] == ':') {
 	    if (p[1] != ':') {
-              rb_raise(rb_eArgError, "undefined class/module %.*s", (int)(p-path), path);
+		rb_raise(rb_eNameError, "wrong constant name %s", path);
             }
 	    p += 2;
 	    pbeg = p;
diff --git a/test/ruby/test_module.rb b/test/ruby/test_module.rb
index 774139b9bc..6cdd832e4d 100644
--- a/test/ruby/test_module.rb
+++ b/test/ruby/test_module.rb
@@ -240,6 +240,24 @@ class TestModule < Test::Unit::TestCase
     assert(!Math.const_defined?("IP"))
   end
 
+  def test_bad_constants
+    [
+      "#<Class:0x7b8b718b>",
+      ":Object",
+      "",
+      ":",
+    ].each do |name|
+      e = assert_raises(NameError) {
+        Object.const_get name
+      }
+      assert_equal("wrong constant name %s" % name, e.message)
+    end
+  end
+
+  def test_leading_colons
+    assert_equal Object, AClass.const_get('::Object')
+  end
+
   def test_const_get
     assert_equal(Math::PI, Math.const_get("PI"))
     assert_equal(Math::PI, Math.const_get(:PI))