SCons/Util/sctyping.py

   1 # SPDX-License-Identifier: MIT
   2 #
   3 # Copyright The SCons Foundation
   4
   5 """Various SCons type aliases.
   6
   7 For representing complex types across the entire repo without risking
   8 circular dependencies, we take advantage of TYPE_CHECKING to import
   9 modules in an tool-only environment. This allows us to introduce
  10 hinting that resolves as expected in IDEs without clashing at runtime.
  11
  12 For consistency, it's recommended to ALWAYS use these aliases in a
  13 type-hinting context, even if the type is actually expected to be
  14 resolved in a given file.
  15 """
  16
  17 from typing import Union, TYPE_CHECKING
  18
  19 if TYPE_CHECKING:
  20     import SCons.Executor
  21
  22
  23 # Because we don't have access to TypeAlias until 3.10, we have to utilize
  24 # 'Union' for all aliases. As it expects at least two entries, anything that
  25 # is only represented with a single type needs to list itself twice.
  26 ExecutorType = Union["SCons.Executor.Executor", "SCons.Executor.Executor"]
  27
  28
  29 # Local Variables:
  30 # tab-width:4
  31 # indent-tabs-mode:nil
  32 # End:
  33 # vim: set expandtab tabstop=4 shiftwidth=4: