1 files changed, 27 insertions, 0 deletions
diff --git a/lib/rake/ext/core.rb b/lib/rake/ext/core.rb
new file mode 100644
index 0000000000..1f3a738906
--- /dev/null
+++ b/lib/rake/ext/core.rb
@@ -0,0 +1,27 @@
+######################################################################
+# Core extension library
+#
+class Module
+  # Check for an existing method in the current class before extending.  IF
+  # the method already exists, then a warning is printed and the extension is
+  # not added.  Otherwise the block is yielded and any definitions in the
+  # block will take effect.
+  #
+  # Usage:
+  #
+  #   class String
+  #     rake_extension("xyz") do
+  #       def xyz
+  #         ...
+  #       end
+  #     end
+  #   end
+  #
+  def rake_extension(method)
+    if method_defined?(method)
+      $stderr.puts "WARNING: Possible conflict with Rake extension: #{self}##{method} already exists"
+    else
+      yield
+    end
+  end
+end