UnboundLocalError:syncdb时在赋值之前引用了本地变量“full\u path”

Question

这里有一个similar question，但在我今天发现的特定情况下，它不能回答这个问题。在

我运行的是openSUSE，在执行syncdb时出现了这个神秘的错误。我把我的发现贴出来是为了帮助处于类似情况下的其他人。在

> python manage.py syncdb
Creating tables ...
Installing custom SQL ...
Installing indexes ...
Traceback (most recent call last):
  File "manage.py", line 14, in <module>
    execute_manager(settings)
  File "/usr/local/lib/python2.7/site-packages/django/core/management/__init__.py",     line 459, in execute_manager
    utility.execute()
  File "/usr/local/lib/python2.7/site-packages/django/core/management/__init__.py",     line 382, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/local/lib/python2.7/site-packages/django/core/management/base.py", line 196, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/usr/local/lib/python2.7/site-packages/django/core/management/base.py", line 232, in execute
    output = self.handle(*args, **options)
  File "/usr/local/lib/python2.7/site-packages/django/core/management/base.py", line 371, in handle
    return self.handle_noargs(**options)
  File "/usr/local/lib/python2.7/site-packages/django/core/management/commands/syncdb.py", line 164, in handle_noargs
    call_command('loaddata', 'initial_data', verbosity=verbosity, database=db)
  File "/usr/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 150, in call_command
    return klass.execute(*args, **defaults)
  File "/usr/local/lib/python2.7/site-packages/django/core/management/base.py", line 232, in execute
    output = self.handle(*args, **options)
  File "/usr/local/lib/python2.7/site-packages/django/core/management/commands/loaddata.py", line 239, in handle
    (full_path, ''.join(traceback.format_exception(sys.exc_type,
UnboundLocalError: local variable 'full_path' referenced before assignment

Answer 1

错误并不漂亮（应该已经捕捉到，并且应该向用户返回完整的错误消息），但是当系统中不存在某些默认或可选的序列化模块时，就会发生这种情况。在

例如，如果在设置.py，在SERIALIZATION_MODULESdict中，提到了wadofstuff.django.serializers.json序列化模块，如果没有安装它，它将返回该错误。在

安装方法如下：

pip install wadofstuff-django-serializers

在openSUSE上，另一种可能是未安装python-xml模块（它不是python-base包的一部分），因此，xml.sax.saxutils的导入可能失败。在

在这种情况下，请安装python-xml，例如通过执行以下操作：

^{pr2}$

它应该会起作用的。在

如果这不起作用，您可以运行pdb在它失败的地方放置一个断点。例如：

> python -m pdb manage.py syncdb
> manage.py(2)<module>() -> from django.core.management import execute_manager
(Pdb) b /usr/local/lib/python2.7/site-packages/django/core/management/commands/loaddata.py:110
Breakpoint 1 at /usr/local/lib/python2.7/site-packages/django/core/management/commands/loaddata.py:110
(Pdb) c
Creating tables ...
Installing custom SQL ...
Installing indexes ...
> /usr/local/lib/python2.7/site-packages/django/core/management/commands/loaddata.py(110)handle()
-> for fixture_label in fixture_labels:
(Pdb) n
> /usr/local/lib/python2.7/site-packages/django/core/management/commands/loaddata.py(111)handle()
-> parts = fixture_label.split('.')

在某些时候，您会发现错误很明显地出现：

ImportError: 'No module named xml.sax.saxutils'