(mostly) Fix configobj copying for py3.6+

src/configobj/__init__.py

@@ -433,7 +433,7 @@ def __setstate__(self, state):
         self.__dict__.update(state[1])
 
     def __reduce__(self):
-        state = (dict(self), self.__dict__)
+        state = (self.copy(), self.__dict__)
         return (__newobj__, (self.__class__,), state)
 
 
@@ -462,6 +462,21 @@ def __init__(self, parent, depth, main, indict=None, name=None):
         for entry, value in indict.items():
             self[entry] = value
 
+    def copy(self):
+        """
+        This will return a dictionary representation without
+        interpolating strings.
+        """
+        # In py36, dict.copy() was changed
+        # so that it used the subclass's __getitem__,
+        # which causes interpolation to occur.
+        # See github issue #188.
+        orig_interp = self.main.interpolation
+        self.main.interpolation = False
+        try:
+            return dict.copy(self)
+        finally:
+            self.main.interpolation = orig_interp
 
     def _initialise(self):
         # the sequence of scalar values in this Section

src/tests/test_configobj.py

@@ -2,7 +2,9 @@
 # pylint: disable=wildcard-import, missing-docstring, no-self-use, bad-continuation
 # pylint: disable=invalid-name, redefined-outer-name, too-few-public-methods
 from __future__ import unicode_literals
+import copy
 import os
+import sys
 import re
 import warnings
 
@@ -176,6 +178,92 @@ def test_interoplation_repr():
     repr(c)
 
 
+class TestCopies(object):
+    @pytest.fixture
+    def simple_conf(self):
+        return ConfigObj(['foo = bar', 'baz = $foo'], interpolation='Template')
+
+    @pytest.fixture
+    def nested_conf(self):
+        return ConfigObj(['[a]', 'foo = bar', 'baz = $foo'],
+                         interpolation='Template')
+
+    def test_simple_copy_method(self, simple_conf):
+        conf_dict = simple_conf.copy()
+        assert conf_dict == {'foo': 'bar', 'baz': '$foo'}
+
+    def test_nested_copy_method(self, nested_conf):
+        conf_dict = nested_conf.copy()
+        assert conf_dict == {'a': {'foo': 'bar', 'baz': '$foo'}}
+
+    @pytest.mark.xfail(sys.version_info >= (3, 6, 7),
+                       reason="dict() now uses self.items()"
+                              " instead of dict.items()",
+                       strict=True)
+    def test_simple_dict(self, simple_conf):
+        conf_dict = dict(simple_conf)
+        assert conf_dict == {'foo': 'bar', 'baz': '$foo'}
+
+    # Not exactly sure why this one does not fail in the same
+    # case as test_simple_dict, but at least this is a step in
+    # the right direction.
+    def test_nested_dict(self, nested_conf):
+        # NOTE: this is a subtle behavior change for v5.1.0.
+        # previously, it would interpolate 'baz'.
+        conf_dict = dict(nested_conf)
+        assert conf_dict == {'a': {'foo': 'bar', 'baz': '$foo'}}
+
+    def test_simple_copy(self, simple_conf):
+        conf_new = copy.copy(simple_conf)
+        assert conf_new is not simple_conf
+        assert isinstance(conf_new, ConfigObj)
+        assert conf_new.copy() == simple_conf.copy()
+        conf_new['foo'] = 'abc'
+        # Ensure the original configobj remains unchanged
+        assert simple_conf['foo'] == 'bar'
+        assert simple_conf['baz'] == 'bar'
+        assert conf_new['baz'] == 'abc'
+        assert conf_new.copy() == {'foo': 'abc', 'baz': '$foo'}
+
+    def test_nested_copy(self, nested_conf):
+        conf_new = copy.copy(nested_conf)
+        assert conf_new is not nested_conf
+        assert isinstance(conf_new, ConfigObj)
+        assert conf_new['a'] is nested_conf['a']
+        assert conf_new.copy() == nested_conf.copy()
+        conf_new['a']['foo'] = 'abc'
+        # Ensure the original configobj was changed
+        assert nested_conf['a']['foo'] == 'abc'
+        assert nested_conf['a']['baz'] == 'abc'
+        assert conf_new['a']['baz'] == 'abc'
+        assert conf_new.copy() == {'a': {'foo': 'abc', 'baz': '$foo'}}
+
+    def test_simple_deepcopy(self, simple_conf):
+        conf_new = copy.deepcopy(simple_conf)
+        assert conf_new is not simple_conf
+        assert isinstance(conf_new, ConfigObj)
+        assert conf_new.copy() == simple_conf.copy()
+        conf_new['foo'] = 'abc'
+        # Ensure the original configobj remains unchanged
+        assert simple_conf['foo'] == 'bar'
+        assert simple_conf['baz'] == 'bar'
+        assert conf_new['baz'] == 'abc'
+        assert conf_new.copy() == {'foo': 'abc', 'baz': '$foo'}
+
+    def test_nested_copy(self, nested_conf):
+        conf_new = copy.deepcopy(nested_conf)
+        assert conf_new is not nested_conf
+        assert isinstance(conf_new, ConfigObj)
+        assert conf_new['a'] is not nested_conf['a']
+        assert conf_new.copy() == nested_conf.copy()
+        conf_new['a']['foo'] = 'abc'
+        # Ensure the original configobj remains unchanged
+        assert nested_conf['a']['foo'] == 'bar'
+        assert nested_conf['a']['baz'] == 'bar'
+        assert conf_new['a']['baz'] == 'abc'
+        assert conf_new.copy() == {'a': {'foo': 'abc', 'baz': '$foo'}}
+
+
 class TestEncoding(object):
     @pytest.fixture
     def ant_cfg(self):