added workaround for py3 issue #21265

2 files changed, 22 insertions, 1 deletions

diff --git a/iniherit/parser.py b/iniherit/parser.py
index 95ccba4..ee9ae6e 100644
--- a/iniherit/parser.py
+++ b/iniherit/parser.py
@@ -154,7 +154,17 @@ class IniheritMixin(object):
         if src.has_option(self.IM_DEFAULTSECT, option) \
             and value == src.get(self.IM_DEFAULTSECT, option):
           continue
-        _real_RawConfigParser.set(dst, dstsect, option, value)
+        if six.PY3 and hasattr(dst, '_interpolation'):
+          # todo: don't do this for systems that have
+          #       http://bugs.python.org/issue21265 fixed
+          try:
+            tmp = dst._interpolation.before_set
+            dst._interpolation.before_set = lambda self,s,o,v,*a,**k: v
+            _real_RawConfigParser.set(dst, dstsect, option, value)
+          finally:
+            dst._interpolation.before_set = tmp
+        else:
+          _real_RawConfigParser.set(dst, dstsect, option, value)
 
 #------------------------------------------------------------------------------
 # todo: i'm a little worried about the diamond inheritance here...
diff --git a/iniherit/test.py b/iniherit/test.py
index dc66e96..676eed7 100644
--- a/iniherit/test.py
+++ b/iniherit/test.py
@@ -133,6 +133,17 @@ kw6 = extend-kw6
                      sorted(dict(foo='bar', zig='zag', x='z').items()))
 
   #----------------------------------------------------------------------------
+  def test_iniherit_interpolation(self):
+    files = [
+      ('config.ini', '[app]\noutput = %(tmpdir)s/var/result.log\n'),
+      ]
+    parser = SafeConfigParser(
+      defaults={'tmpdir': '/tmp'}, loader=ByteLoader(dict(files)))
+    parser.read('config.ini')
+    self.assertEqual(parser.get('app', 'output'), '/tmp/var/result.log')
+    self.assertEqual(parser.get('app', 'output', raw=True), '%(tmpdir)s/var/result.log')
+
+  #----------------------------------------------------------------------------
   def test_iniherit_invalidInterpolationValues(self):
     files = [
       ('config.ini', '[logger]\ntimefmt=%H:%M:%S\n'),