fix issue #165 Python2 raising error when Unicode text involved in duplicate key warning.0.15.55

I could only reproduce this in Python2, finally fixed it.

*When this change indeed resolves your problem, please **Close** this issue*.
*(You can do so using the WorkFlow pull-down (close to the top right of this page))*

6 files changed, 49 insertions, 7 deletions

diff --git a/CHANGES b/CHANGES
index c7f4cb9..9d44f14 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,19 @@
+[0, 15, 55]: 2018-08-14
+
+  - unmade ``CommentedSeq`` a subclass of ``list``. It is now
+    indirectly a subclass of the standard
+    ``collections.abc.MutableSequence`` (without .abc if you are
+    still on Python2.7). If you do ``isinstance(yaml.load('[1, 2]'),
+    list)``) anywhere in your code replace ``list`` with
+    ``MutableSequence``.  Directly, ``CommentedSeq`` is a subclass of
+    the abstract baseclass ``ruamel.yaml.compat.MutableScliceableSequence``,
+    with the result that *(extended) slicing is supported on 
+    ``CommentedSeq``*.
+    (reported by `Stuart Berg <https://bitbucket.org/stuarteberg/>`__)
+  - duplicate keys (or their values) with non-ascii now correctly
+    report in Python2, instead of raising a Unicode error.
+    (Reported by `Jonathan Pyle <https://bitbucket.org/jonathan_pyle/>`__)
+
 [0, 15, 54]: 2018-08-13
 
   - fix issue where a comment could pop-up twice in the output (reported by 
diff --git a/README.rst b/README.rst
index 9182e43..7668f3b 100644
--- a/README.rst
+++ b/README.rst
@@ -4,8 +4,8 @@ ruamel.yaml
 
 ``ruamel.yaml`` is a YAML 1.2 loader/dumper package for Python.
 
-:version:       0.15.54
-:updated:       2018-08-13
+:version:       0.15.55
+:updated:       2018-08-14
 :documentation: http://yaml.readthedocs.io
 :repository:    https://bitbucket.org/ruamel/
 :pypi:          https://pypi.org/project/ruamel.yaml/
@@ -54,6 +54,22 @@ ChangeLog
 
 .. should insert NEXT: at the beginning of line for next key (with empty line)
 
+0.15.55 (2018-08-14):
+
+  - unmade ``CommentedSeq`` a subclass of ``list``. It is now
+    indirectly a subclass of the standard
+    ``collections.abc.MutableSequence`` (without .abc if you are
+    still on Python2.7). If you do ``isinstance(yaml.load('[1, 2]'),
+    list)``) anywhere in your code replace ``list`` with
+    ``MutableSequence``.  Directly, ``CommentedSeq`` is a subclass of
+    the abstract baseclass ``ruamel.yaml.compat.MutableScliceableSequence``,
+    with the result that *(extended) slicing is supported on 
+    ``CommentedSeq``*.
+    (reported by `Stuart Berg <https://bitbucket.org/stuarteberg/>`__)
+  - duplicate keys (or their values) with non-ascii now correctly
+    report in Python2, instead of raising a Unicode error.
+    (Reported by `Jonathan Pyle <https://bitbucket.org/jonathan_pyle/>`__)
+
 0.15.54 (2018-08-13):
 
   - fix issue where a comment could pop-up twice in the output (reported by 
diff --git a/__init__.py b/__init__.py
index cfddf1b..5c994e3 100644
--- a/__init__.py
+++ b/__init__.py
@@ -7,8 +7,8 @@ if False:  # MYPY
 
 _package_data = dict(
     full_package_name='ruamel.yaml',
-    version_info=(0, 15, 54),
-    __version__='0.15.54',
+    version_info=(0, 15, 55),
+    __version__='0.15.55',
     author='Anthon van der Neut',
     author_email='a.van.der.neut@ruamel.eu',
     description='ruamel.yaml is a YAML parser/emitter that supports roundtrip preservation of comments, seq/map flow style, and map key order',  # NOQA
diff --git a/_doc/_static/pypi.svg b/_doc/_static/pypi.svg
index 369335f..aa24ad4 100644
--- a/_doc/_static/pypi.svg
+++ b/_doc/_static/pypi.svg
@@ -1 +1 @@
-<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="86" height="20"><linearGradient id="b" x2="0" y2="100%"><stop offset="0" stop-color="#bbb" stop-opacity=".1"/><stop offset="1" stop-opacity=".1"/></linearGradient><clipPath id="a"><rect width="86" height="20" rx="3" fill="#fff"/></clipPath><g clip-path="url(#a)"><path fill="#555" d="M0 0h33v20H0z"/><path fill="#007ec6" d="M33 0h53v20H33z"/><path fill="url(#b)" d="M0 0h86v20H0z"/></g><g fill="#fff" text-anchor="middle" font-family="DejaVu Sans,Verdana,Geneva,sans-serif" font-size="110"> <text x="175" y="150" fill="#010101" fill-opacity=".3" transform="scale(.1)" textLength="230">pypi</text><text x="175" y="140" transform="scale(.1)" textLength="230">pypi</text><text x="585" y="150" fill="#010101" fill-opacity=".3" transform="scale(.1)" textLength="430">0.15.54</text><text x="585" y="140" transform="scale(.1)" textLength="430">0.15.54</text></g> </svg>
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="86" height="20"><linearGradient id="b" x2="0" y2="100%"><stop offset="0" stop-color="#bbb" stop-opacity=".1"/><stop offset="1" stop-opacity=".1"/></linearGradient><clipPath id="a"><rect width="86" height="20" rx="3" fill="#fff"/></clipPath><g clip-path="url(#a)"><path fill="#555" d="M0 0h33v20H0z"/><path fill="#007ec6" d="M33 0h53v20H33z"/><path fill="url(#b)" d="M0 0h86v20H0z"/></g><g fill="#fff" text-anchor="middle" font-family="DejaVu Sans,Verdana,Geneva,sans-serif" font-size="110"> <text x="175" y="150" fill="#010101" fill-opacity=".3" transform="scale(.1)" textLength="230">pypi</text><text x="175" y="140" transform="scale(.1)" textLength="230">pypi</text><text x="585" y="150" fill="#010101" fill-opacity=".3" transform="scale(.1)" textLength="430">0.15.55</text><text x="585" y="140" transform="scale(.1)" textLength="430">0.15.55</text></g> </svg>
diff --git a/_test/test_api_change.py b/_test/test_api_change.py
index 43c8c90..b5b3d00 100644
--- a/_test/test_api_change.py
+++ b/_test/test_api_change.py
@@ -215,7 +215,6 @@ class TestFlowStyle:
 
 class TestOldAPI:
     @pytest.mark.skipif(sys.version_info >= (3, 0), reason='ok on Py3')
-    @pytest.mark.xfail(strict=True)
     def test_duplicate_keys_02(self):
         # Issue 165 unicode keys in error/warning
         from ruamel.yaml import safe_load
diff --git a/constructor.py b/constructor.py
index 9de28d0..8e1da70 100644
--- a/constructor.py
+++ b/constructor.py
@@ -248,11 +248,19 @@ class BaseConstructor(object):
         # type: (Any, Any, Any, Any, Any) -> None
         if key in mapping:
             if not self.allow_duplicate_keys:
+                mk = mapping.get(key)
+                if PY2:
+                    if isinstance(key, unicode):
+                        key = key.encode('utf-8')
+                    if isinstance(value, unicode):
+                        value = value.encode('utf-8')
+                    if isinstance(mk, unicode):
+                        mk = mk.encode('utf-8')
                 args = [
                     'while constructing a mapping',
                     node.start_mark,
                     'found duplicate key "{}" with value "{}" '
-                    '(original value: "{}")'.format(key, value, mapping.get(key)),
+                    '(original value: "{}")'.format(key, value, mk),
                     key_node.start_mark,
                     """
                     To suppress this check see:
@@ -272,6 +280,9 @@ class BaseConstructor(object):
         # type: (Any, Any, Any, Any, Any) -> None
         if key in setting:
             if not self.allow_duplicate_keys:
+                if PY2:
+                    if isinstance(key, unicode):
+                        key = key.encode('utf-8')
                 args = [
                     'while constructing a set',
                     node.start_mark,