Fix multiple leading dots in GlobalObject/Interface.issue41

Fixes #41.

3 files changed, 15 insertions, 6 deletions

diff --git a/CHANGES.rst b/CHANGES.rst
index 1a85654..52a1426 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -4,7 +4,9 @@ Changes
 4.2.2 (unreleased)
 ------------------
 
-- Nothing changed yet.
+- Fix ``GlobalObject`` (and ``GlobalInterface``) no longer allowing
+  multiple leading dots. See `issue 41
+  <https://github.com/zopefoundation/zope.configuration/issues/41>`_.
 
 
 4.2.1 (2018-09-26)
diff --git a/src/zope/configuration/fields.py b/src/zope/configuration/fields.py
index 70527a5..1730431 100644
--- a/src/zope/configuration/fields.py
+++ b/src/zope/configuration/fields.py
@@ -80,7 +80,7 @@ class GlobalObject(Field):
             # package, but not accepted by DottedName. Take care,
             # though, because a single dot is valid to resolve, but
             # not valid to pass to DottedName (as an empty string)
-            to_validate = name[1:] if name.startswith('.') else name
+            to_validate = name.lstrip('.')
             if to_validate:
                 self._DOT_VALIDATOR.validate(to_validate)
         except ValidationError as v:
diff --git a/src/zope/configuration/tests/test_fields.py b/src/zope/configuration/tests/test_fields.py
index 6964957..baa4023 100644
--- a/src/zope/configuration/tests/test_fields.py
+++ b/src/zope/configuration/tests/test_fields.py
@@ -95,7 +95,7 @@ class GlobalObjectTests(unittest.TestCase, _ConformsToIFromUnicode):
         self.assertIs(found, _target)
         self.assertEqual(context._resolved, 'tried')
 
-    def test_fromUnicode_w_resolve_dot(self):
+    def test_fromUnicode_w_resolve_dots(self):
         _target = object()
         class Context(object):
             _resolved = None
@@ -105,9 +105,16 @@ class GlobalObjectTests(unittest.TestCase, _ConformsToIFromUnicode):
         go = self._makeOne()
         context = Context()
         bound = go.bind(context)
-        found = bound.fromUnicode('.')
-        self.assertIs(found, _target)
-        self.assertEqual(context._resolved, '.')
+        for name in (
+                '.',
+                '..',
+                '.foo',
+                '..foo.bar'
+        ):
+            __traceback_info__ = name
+            found = bound.fromUnicode(name)
+            self.assertIs(found, _target)
+            self.assertEqual(context._resolved, name)
 
     def test_fromUnicode_w_resolve_but_validation_fails(self):
         from zope.schema import Text