1# Copyright 2021 The Cirq Developers
2#
3# Licensed under the Apache License, Version 2.0 (the "License");
4# you may not use this file except in compliance with the License.
5# You may obtain a copy of the License at
6#
7#     https://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS,
11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12# See the License for the specific language governing permissions and
13# limitations under the License.
14
15import os
16import sys
17
18
19def explode(req: str):
20    """Returns the exploded dependency list for a requirements file.
21
22    As requirements files can include other requirements files with the -r directive, it can be
23    useful to see a flattened version of all the constraints. This method unrolls a requirement file
24    and produces a list of strings for each constraint line in the order of inclusion.
25
26    Args:
27        req: path to a requirements file.
28    Returns:
29         list of lines of requirements
30    """
31    res = []
32    d = os.path.dirname(req)
33    with open(req) as f:
34        for l in f.readlines():
35            l = l.rstrip("\n")
36            l = l.lstrip(" ")
37            if l.startswith("-r"):
38                include = l.lstrip(" ").lstrip("-r").lstrip(" ")
39                # assuming relative includes always
40                res += explode(os.path.join(d, include))
41            elif l:
42                res += [l]
43    return res
44
45
46if __name__ == '__main__':
47    print('\n'.join(explode(sys.argv[1])))
48