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#
# -------------------------------------------------------------------------
# Copyright (c) 2015-2017 AT&T Intellectual Property
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# -------------------------------------------------------------------------
#
from yaml.constructor import ConstructorError
from yaml.nodes import MappingNode
try:
from yaml import CLoader as Loader
except ImportError:
from yaml import Loader
class UniqueKeyLoader(Loader):
"""Unique Key Loader for PyYAML
Ensures no duplicate keys on any given level.
https://gist.github.com/pypt/94d747fe5180851196eb#gistcomment-2084028
"""
DUPLICATE_KEY_PROBLEM_MARK = "found duplicate key"
def construct_mapping(self, node, deep=False):
"""Check for duplicate keys while constructing a mapping."""
if not isinstance(node, MappingNode):
raise ConstructorError(
None, None, "expected a mapping node, but found %s" % node.id,
node.start_mark)
mapping = {}
for key_node, value_node in node.value:
key = self.construct_object(key_node, deep=deep)
try:
hash(key)
except (TypeError) as exc:
raise ConstructorError("while constructing a mapping",
node.start_mark,
"found unacceptable key (%s)" % exc,
key_node.start_mark)
# check for duplicate keys
if key in mapping:
raise ConstructorError("while constructing a mapping",
node.start_mark,
self.DUPLICATE_KEY_PROBLEM_MARK,
key_node.start_mark)
value = self.construct_object(value_node, deep=deep)
mapping[key] = value
return mapping
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