为什么 snapcraft 会失败：模块“magic”没有属性“open”

Question

当尝试捕捉项目时，我们从 snapcraft 返回此错误：

Traceback (most recent call last):
  File "/usr/bin/snapcraft", line 31, in <module>
    snapcraft.main.main()
  File "/usr/lib/python3/dist-packages/snapcraft/main.py", line 226, in main
    return run(args, project_options)
  File "/usr/lib/python3/dist-packages/snapcraft/main.py", line 282, in run
    lifecycle.snap(project_options, args['<directory>'], args['--output'])
  File "/usr/lib/python3/dist-packages/snapcraft/internal/lifecycle.py", line 289, in snap
    snap = execute('prime', project_options)
  File "/usr/lib/python3/dist-packages/snapcraft/internal/lifecycle.py", line 103, in execute
    _Executor(config, project_options).run(step, part_names)
  File "/usr/lib/python3/dist-packages/snapcraft/internal/lifecycle.py", line 161, in run
    self._run_step(step, part, part_names)
  File "/usr/lib/python3/dist-packages/snapcraft/internal/lifecycle.py", line 197, in _run_step
    getattr(part, step)()
  File "/usr/lib/python3/dist-packages/snapcraft/internal/pluginhandler.py", line 383, in prime
    dependencies = _find_dependencies(self.snapdir, snap_files)
  File "/usr/lib/python3/dist-packages/snapcraft/internal/pluginhandler.py", line 723, in _find_dependencies
    ms = magic.open(magic.NONE)
AttributeError: module 'magic' has no attribute 'open'

这是什么意思，如何解决？

Answer 1

有两个名为 magic 的 python 模块，具有不同的 API。

snapcraft 所需的软件包被打包为名为 python3-magic 的 deb。它对应于 pypi 中的模块 file-magic：https://pypi.python.org/pypi/file-magic

另一个在 pypi 中被称为魔法：https://pypi.python.org/pypi/magic

因此如果你这样做：

sudo pip install magic

您将得到错误的版本，并且它将被安装到优先于使用 apt 安装的 python3-magic deb 的路径。这就是导致错误的原因。

要检查您是否从 pip 安装了其他魔法模块：

pip3 list | grep magic

并将其删除并修复 snapcraft：

pip3 uninstall magic

Answer 2

截至撰写本文时，解决方案是：

pip3 uninstall python-magic
pip3 install file-magic