rt set handling now checks for duplicate keys

4 files changed, 23 insertions, 3 deletions

diff --git a/README.rst b/README.rst
index f5130b0..6422b7c 100644
--- a/README.rst
+++ b/README.rst
@@ -32,6 +32,9 @@ ChangeLog
 
 .. should insert NEXT: at the beginning of line for next key
 
+NEXT:
+  - a set with duplicate elements now throws error in rt loading
+
 0.15.5 (2017-06-08):
   - repeat `load()` on a single `YAML()` instance would fail.
 
diff --git a/__init__.py b/__init__.py
index d8bd99c..037bed1 100644
--- a/__init__.py
+++ b/__init__.py
@@ -11,8 +11,8 @@ if False:  # MYPY
 
 _package_data = dict(
     full_package_name='ruamel.yaml',
-    version_info=(0, 15, 5),
-    __version__='0.15.5',
+    version_info=(0, 15, 6, 'dev'),
+    __version__='0.15.6.dev',
     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/_test/test_api_change.py b/_test/test_api_change.py
index e33e8bc..bd56881 100644
--- a/_test/test_api_change.py
+++ b/_test/test_api_change.py
@@ -7,6 +7,7 @@ testing of anchors and the aliases referring to them
 """
 
 import sys
+import textwrap
 import pytest
 from ruamel.yaml import YAML
 from ruamel.yaml.constructor import DuplicateKeyError
@@ -97,3 +98,17 @@ class TestRead:
         yaml = YAML()
         yaml.load('a: 1')
         yaml.load('a: 1')  # did not work in 0.15.4
+
+
+class TestDuplSet:
+    def test_dupl_set_00(self):
+        # round-trip-loader should except
+        yaml = YAML()
+        with pytest.raises(DuplicateKeyError):
+            yaml.load(textwrap.dedent("""\
+            !!set
+            ? a
+            ? b
+            ? c
+            ? a
+            """))
diff --git a/constructor.py b/constructor.py
index 83cbbec..a37f794 100644
--- a/constructor.py
+++ b/constructor.py
@@ -246,7 +246,7 @@ class BaseConstructor(object):
                     "while constructing a mapping", node.start_mark,
                     'found duplicate key "{}" with value "{}" '
                     '(original value: "{}")'.format(
-                        key, value, mapping[key]), key_node.start_mark,
+                        key, value, mapping.get(key)), key_node.start_mark,
                     """
                     To suppress this check see:
                         http://yaml.readthedocs.io/en/latest/api.html#duplicate-keys
@@ -1243,7 +1243,9 @@ class RoundTripConstructor(SafeConstructor):
                     raise ConstructorError(
                         "while constructing a mapping", node.start_mark,
                         "found unhashable key", key_node.start_mark)
+            # construct but should be null
             value = self.construct_object(value_node, deep=deep)  # NOQA
+            self.check_mapping_key(node, key_node, typ, key, value)
             if key_node.comment:
                 typ._yaml_add_comment(key_node.comment, key=key)
             if value_node.comment: