python debug调试
pdb
2种调试方法
- 在程序中设置断点
# test_pdb.py
import pdb
t = [1,2]
pdb.set_trace()
程序运行到 pdb.set_trace()时会中断，此时可以通过pdb查看上下文变量`
# /bin/python test_pdb.py
--Return--
> test_pdb.py(4)<module>()->None
-> pdb.set_trace()
(Pdb) l
1 import pdb
2
3 t = [1,2]
4 -> pdb.set_trace()
[EOF]
(Pdb) p t
[1, 2]
(Pdb)
- 以
-i运行.python文件
# test_pdb.py
t = [1,2]
print(t[99])
执行 python3 -i test_pdb.py
如下:
# python3 -i test_pdb.py
Traceback (most recent call last):
File "test_pdb.py", line 4, in <module>
print(t[99])
IndexError: list index out of range
>>> import pdb
>>> pdb.pm()
> test_pdb.py(4)<module>()
-> print(t[99])
(Pdb) l
1 import pdb
2
3 t = [1,2]
4 -> print(t[99])
5
[EOF]
(Pdb) p t
[1, 2]
(Pdb) p len(t)
2
(Pdb)
需要注意的点
以 -i 运行调试必须是程序发生异常时，才能进行 pdb 调试。如果自身设置了异常捕获，此时进行pdb调试会发生异常。
详见：https://bugs.python.org/issue39208
示例如下：
import traceback
try:
t = [1,2]
print(t[99])
except Exception as e:
print(traceback.format_exc())
执行 python -i test_pdb.py
# /bin/python -i test_pdb.py
Traceback (most recent call last):
File "test_pdb.py", line 5, in <module>
print(t[99])
IndexError: list index out of range
>>> import pdb
>>> pdb.pm()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib64/python3.6/pdb.py", line 1604, in pm
post_mortem(sys.last_traceback)
AttributeError: module 'sys' has no attribute 'last_traceback'