# Copyright 2020 The Bazel Authors. All rights reserved.
#
# 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.

"""Used by top-level exports.bzl."""

def dict_union(*dicts):
    """Returns the strict union of zero or more dicts."""
    result = {}
    for d in dicts:
        for k, v in d.items():
            if k in result:
                fail("Duplicate key: '%s'" % k)
            result[k] = v
    return result
