backend: auto-generate error constants on const_missing

This way, folks can rescue for exceptions we haven't defined,
yet.

1 files changed, 8 insertions, 0 deletions

diff --git a/lib/mogilefs/backend.rb b/lib/mogilefs/backend.rb
index 0319525..b48764c 100644
--- a/lib/mogilefs/backend.rb
+++ b/lib/mogilefs/backend.rb
@@ -42,6 +42,14 @@ class MogileFS::Backend
     BACKEND_ERRORS[err_snake] = const_get(err_camel)
   end
 
+  def self.const_missing(name)
+    if /Error\z/ =~ name.to_s
+      const_set(name, Class.new(MogileFS::Error))
+    else
+      super name
+    end
+  end
+
   ##
   # The last error