AttributeError: 'NoneType' object has no attribute 'strip'

Question

AttributeError: 'NoneType' object has no attribute 'strip'

nateozem opened this issue 7 years ago · comments

Using lldb v360.99.0 (v4.0.0.1), I'll get the following error:

$ lldb 
An error occurred while loading Voltron:

Traceback (most recent call last):
  File "./lib/python2.7/site-packages/voltron-0.1.7-py2.7.egg/voltron/entry.py", line 99, in <module>
	voltron.command = plugin.command_class(*args)
  File "./lib/python2.7/site-packages/voltron-0.1.7-py2.7.egg/voltron/plugins/debugger/dbg_lldb.py", line 549, in __init__
	self.adaptor.command("script import voltron")
  File "./lib/python2.7/site-packages/voltron-0.1.7-py2.7.egg/voltron/dbg.py", line 82, in inner
	raise e
AttributeError: 'NoneType' object has no attribute 'strip'

Please ensure Voltron is installed correctly per the documentation: https://github.com/snare/voltron/wiki/Installation

lldb info:

$ lldb -vV
lldb-360.99.0

$ lldb -P
/usr/local/Cellar/llvm/4.0.0_1/lib/python2.7/site-packages

voltron:

$ lldb 
(lldb) script
Python Interactive Interpreter. To exit, type 'quit()', 'exit()' or Ctrl-D.
>>> import voltron
>>> print voltron
<module 'voltron' from './lib/python2.7/site-packages/voltron-0.1.7-py2.7.egg/voltron/__init__.pyc'>

I'm sure I've installed things correctly, however I'm using updated version of
lldb from homebrew.

So, would lldb v4.x.x be the issue?

The reason I asked because from the debug log I gathered (shown below), there isn't any conflicts with
lldb and python.

(Pdb) step
> ./lib/python2.7/site-packages/voltron-0.1.7-py2.7.egg/voltron/plugins/debugger/dbg_lldb.py(394)command()
-> res = lldb.SBCommandReturnObject()
(Pdb) pp lldb
<module 'lldb' from '/usr/local/Cellar/llvm/4.0.0_1/lib/python2.7/site-packages/lldb/__init__.pyc'>
(Pdb) n
> ./lib/python2.7/site-packages/voltron-0.1.7-py2.7.egg/voltron/plugins/debugger/dbg_lldb.py(395)command()
-> ci = self.host.GetCommandInterpreter()
(Pdb) pp res
<lldb.SBCommandReturnObject; proxy of <Swig Object of type 'lldb::SBCommandReturnObject *' at 0x11368ec60> >
(Pdb) pp self
<dbg_lldb.LLDBAdaptor object at 0x113a35410>
(Pdb) pp command
'script import voltron'
(Pdb) pp voltron
<module 'voltron' from './lib/python2.7/site-packages/voltron-0.1.7-py2.7.egg/voltron/__init__.pyc'>
(Pdb) list
392                 # for some reason this doesn't work - figure it out
393                 if command:
394                     res = lldb.SBCommandReturnObject()
395                     ci = self.host.GetCommandInterpreter()
396                     ci.HandleCommand(str(command), res, False)
397  ->                 if res.Succeeded():
398                         return res.GetOutput().strip()
399                     else:
400                         raise Exception(res.GetError().strip())
401                 else:
402                     raise Exception("No command specified")
(Pdb) n
> ./lib/python2.7/site-packages/voltron-0.1.7-py2.7.egg/voltron/plugins/debugger/dbg_lldb.py(398)command()
-> return res.GetOutput().strip()
(Pdb) list
393                 if command:
394                     res = lldb.SBCommandReturnObject()
395                     ci = self.host.GetCommandInterpreter()
396                     ci.HandleCommand(str(command), res, False)
397                     if res.Succeeded():
398  ->                     return res.GetOutput().strip()
399                     else:
400                         raise Exception(res.GetError().strip())
401                 else:
402                     raise Exception("No command specified")
403
(Pdb) n
AttributeError: "'NoneType' object has no attribute 'strip'"
> ./lib/python2.7/site-packages/voltron-0.1.7-py2.7.egg/voltron/plugins/debugger/dbg_lldb.py(398)command()
-> return res.GetOutput().strip()

Any good idea to resolve this? I wouldn't mind digging into the issue.

nateozem commented 7 years ago

sure

snare · Answer 1 · Thu May 04 2017 23:47:42 GMT+0800 (China Standard Time)

I’ve never tried it with LLDB from homebrew, only Xcode’s LLDB.

> ./lib/python2.7/site-packages/voltron-0.1.7-py2.7.egg/voltron/plugins/debugger/dbg_lldb.py(398)command() -> return res.GetOutput().strip() (Pdb) list 393 if command: 394 res = lldb.SBCommandReturnObject() 395 ci = self.host.GetCommandInterpreter() 396 ci.HandleCommand(str(command), res, False) 397 if res.Succeeded(): 398 -> return res.GetOutput().strip() 399 else: 400 raise Exception(res.GetError().strip()) 401 else: 402 raise Exception("No command specified") 403 (Pdb) n AttributeError: "'NoneType' object has no attribute 'strip'" > ./lib/python2.7/site-packages/voltron-0.1.7-py2.7.egg/voltron/plugins/debugger/dbg_lldb.py(398)command() -> return res.GetOutput().strip() Any good idea to resolve this? I wouldn't mind digging into the issue.

This makes it look like GetOutput() might be returning None rather than an empty string when there is no output in the newer version. Maybe try modifying the code to handle that case? Otherwise I’d say something more fundamental is going wrong. Can you `pp command` before there and show me what command it’s running? Also inspect the `res` object? I can’t remember what props it’ll have but the LLDB API doc will tell you if you want to dig into it.

nateozem · Answer 2 · Fri May 05 2017 00:10:51 GMT+0800 (China Standard Time)

Here are the output for command and res:

(Pdb) pp command
'script import voltron'
(Pdb) pp res
<lldb.SBCommandReturnObject; proxy of <Swig Object of type 'lldb::SBCommandReturnObject *' at 0x11368ec60> >

Thanks. I'll try to see what I can do.

snare · Answer 3 · Fri May 05 2017 00:14:30 GMT+0800 (China Standard Time)

Hmm yeah it’s possible it’s just returning None now. I’d try changing this line: 398 -> return res.GetOutput().strip() To: output = res.GetOutput() return output.strip() if output else None

…

On May 4, 2017, at 9:10 AM, nateozem ***@***.***> wrote: Here are the output for command and res: (Pdb) pp command 'script import voltron' (Pdb) pp res <lldb.SBCommandReturnObject; proxy of <Swig Object of type 'lldb::SBCommandReturnObject *' at 0x11368ec60> > Thanks. I'll try to see what I can do. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#197 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAey8QUJPhGRGOcvq4VUzq9os6YlE2ctks5r2fiMgaJpZM4NQ1wa>.

nateozem · Answer 4 · Fri May 05 2017 02:01:36 GMT+0800 (China Standard Time)

Cool thanks. I'll give it a try.

nateozem · Answer 5 · Fri May 05 2017 02:37:36 GMT+0800 (China Standard Time)

Nice. It works. I'll create PR (even though I just copy and paste your snippet), unless told otherwise.

I wonder why it works?

snare · Answer 6 · Fri May 05 2017 02:43:58 GMT+0800 (China Standard Time)

Sure send me a PR and I'll merge it. Make it return "" rather than None though actually.

…

On May 4, 2017, at 11:37 AM, nateozem ***@***.***> wrote: Nice. It works. I'll create PR (even though I just copy and paste your snippet), unless told otherwise. I wonder why it works? — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#197 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAey8S25Nj9iFmnuwpULGEstL96wei5Oks5r2hrzgaJpZM4NQ1wa>.

Pablo Hernandez-Cerdan · Answer 7 · Sat Jul 15 2017 19:37:56 GMT+0800 (China Standard Time)

Facing this, is it merged?

nateozem · Answer 8 · Mon Jul 17 2017 00:49:56 GMT+0800 (China Standard Time)

yes, it's. I problem went away.

Do you have the same version or have you pulled the latest commit from master?