SyntaxError Generator expression must be parenthesized

环境：

• Windows10
• python3.7.0
• Django1.11.15

异常

启动Django时抛出以下异常：

Unhandled exception in thread started by <function check_errors.<locals>.wrapper at 0x0000024D934BDD08>
Traceback (most recent call last):
  File "C:\Python37\lib\site-packages\django\utils\autoreload.py", line 228, in wrapper
    fn(*args, **kwargs)
  File "C:\Python37\lib\site-packages\django\core\management\commands\runserver.py", line 116, in inner_run
    autoreload.raise_last_exception()
  File "C:\Python37\lib\site-packages\django\utils\autoreload.py", line 251, in raise_last_exception
    six.reraise(*_exception)
  File "C:\Python37\lib\site-packages\django\utils\six.py", line 685, in reraise
    raise value.with_traceback(tb)
  File "C:\Python37\lib\site-packages\django\utils\autoreload.py", line 228, in wrapper
    fn(*args, **kwargs)
  File "C:\Python37\lib\site-packages\django\__init__.py", line 27, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "C:\Python37\lib\site-packages\django\apps\registry.py", line 85, in populate
    app_config = AppConfig.create(entry)
  File "C:\Python37\lib\site-packages\django\apps\config.py", line 94, in create
    module = import_module(entry)
  File "C:\Python37\lib\importlib\__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
  File "<frozen importlib._bootstrap>", line 983, in _find_and_load
  File "<frozen importlib._bootstrap>", line 967, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 728, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "C:\Python37\lib\site-packages\django\contrib\admin\__init__.py", line 4, in <module>
    from django.contrib.admin.filters import (
  File "C:\Python37\lib\site-packages\django\contrib\admin\filters.py", line 10, in <module>
    from django.contrib.admin.options import IncorrectLookupParameters
  File "C:\Python37\lib\site-packages\django\contrib\admin\options.py", line 13, in <module>
    from django.contrib.admin import helpers, widgets
  File "C:\Python37\lib\site-packages\django\contrib\admin\widgets.py", line 152
    '%s=%s' % (k, v) for k, v in params.items(),
    ^
SyntaxError: Generator expression must be parenthesized

解决方法

• 把'%s=%s' % (k, v) for k, v in params.items(),中的后边的逗号去掉就ok了

Linux下的解决方法

Linux下启动失败跑抛出异常，和Windows下一样，查看抛出异常的最后一个提示的路径和行号。使用sudo编进该路径下的该py文件，方法同上，保存就ok了

类似的文件路径

sudo vi /usr/local/lib/python3.7/site-packages/django/contrib/admin/widgets.py

修改源码

related_url += '?' + '&'.join(
    '%s=%s' % (k, v) for k, v in params.items(),
)
# 修改:
related_url += '?' + '&'.join(
    '%s=%s' % (k, v) for k, v in params.items()
)