是否有传播错误和警告细节的通用模式？我所说的错误是指应该导致代码流停止的严重问题。警告是指值得通知用户问题的问题，但太微不足道而无法停止程序流程。
我目前使用异常来处理硬错误，并使用 Python 日志框架来记录警告。但是现在我想在当前正在处理的记录的数据库字段中记录警告。我想，我希望警告以与异常相同的方式冒泡，但不会停止程序流。
>>> import logging
>>>
>>> def process_item(item):
... if item:
... if item == 'broken':
... logging.warning('soft error, continue with next item')
... else:
... raise Exception('hard error, cannot continue')
...
>>> process_item('good')
>>> process_item(None)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<stdin>", line 6, in process_item
Exception: hard error, cannot continue
>>> process_item('broken')
WARNING:root:soft error, continue with next item
这个例子（和我当前的问题）是在 Python 中，但它也应该适用于其他语言，但也有例外。
按照David的建议和对下面示例的简要介绍，Python 的warnings模块是要走的路。
import warnings
class MyWarning(Warning):
pass
def causes_warnings():
print 'enter causes_warnings'
warnings.warn("my warning", MyWarning)
print 'leave causes_warnings'
def do_stuff():
print 'enter do_stuff'
causes_warnings()
causes_warnings()
causes_warnings()
print 'leave do_stuff'
with warnings.catch_warnings(record=True) as w:
# Cause all warnings to always be triggered.
warnings.simplefilter("always")
# Trigger a number of warnings.
do_stuff()
# Do something (not very) useful with the warnings generated
print 'Warnings:',','.join([str(warning.message) for warning in w])
输出：
enter do_stuff
enter causes_warnings
leave causes_warnings
enter causes_warnings
leave causes_warnings
enter causes_warnings
leave causes_warnings
leave do_stuff
Warnings: my warning,my warning,my warning
注意：Python 2.6+ 是catch_warnings.