ipython: Tab complete of args list runs unexpected property code

Ipython executes parts of my code when using the autocomplete functionality.

System info:

>> python -c "import IPython; print(IPython.sys_info())"
{'commit_hash': u'8b97549',
 'commit_source': 'repository',
 'default_encoding': 'UTF-8',
 'ipython_path': '/home/ipython/IPython',
 'ipython_version': '4.1.0-dev',
 'os_name': 'posix',
 'platform': 'Linux-3.16.0-53-generic-x86_64-with-Ubuntu-14.04-trusty',
 'sys_executable': '/home/ipython/virtual_environment/bin/python',
 'sys_platform': 'linux2',
 'sys_version': '2.7.6 (default, Jun 22 2015, 17:58:13) \n[GCC 4.8.2]'}

Example:

In [1]: class Hello(object):                                                                                                                                            
    @property                                                                   
    def hello(self):                                                                
        print "It's me" 

In [2]: h=Hello()

Trying to autocomplete h.b, h.hello or h.b( works as I would expect. However h.h( or h.hello( results in

In [3]: h.h(It's me
Display all ... possibilities? (y or n)
....
In [3]: h.h(

which resulted in an unexpected printout.

About this issue

Original URL
State: open
Created 9 years ago
Reactions: 2
Comments: 16 (3 by maintainers)

Most upvoted comments

Curiously, this also happens with plain Python. I just reproduced this in a fresh minimal conda environment with only Python 3.9, and see that it is in fact executing on autocompletion of h.<TAB>, but there is no IPython nor Jedi around:

(ipython-9094) bilderbuchi@osprey:~$ python
Python 3.9.1 (default, Dec 11 2020, 14:32:07) 
[GCC 7.3.0] :: Anaconda, Inc. on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> class Hello:
...     @property
...     def hello(self):
...         print('In an executing property')
... 
>>> h = Hello()
>>> h.In an executing property
hello
In an executing property
>>> 
[4]+  Stopped                 python
(ipython-9094) bilderbuchi@osprey:~$ conda list
# packages in environment at /home/bilderbuchi/anaconda3/envs/ipython-9094:
#
# Name                    Version                   Build  Channel
_libgcc_mutex             0.1                        main  
ca-certificates           2020.12.8            h06a4308_0  
certifi                   2020.12.5        py39h06a4308_0  
ld_impl_linux-64          2.33.1               h53a641e_7  
libedit                   3.1.20191231         h14c3975_1  
libffi                    3.3                  he6710b0_2  
libgcc-ng                 9.1.0                hdf63c60_0  
libstdcxx-ng              9.1.0                hdf63c60_0  
ncurses                   6.2                  he6710b0_1  
openssl                   1.1.1i               h27cfd23_0  
pip                       20.3.3           py39h06a4308_0  
python                    3.9.1                hdb3f193_2  
readline                  8.0                  h7b6447c_0  
setuptools                51.0.0           py39h06a4308_2  
sqlite                    3.33.0               h62c20be_0  
tk                        8.6.10               hbc83047_0  
tzdata                    2020d                h14c3975_0  
wheel                     0.36.2             pyhd3eb1b0_0  
xz                        5.2.5                h7b6447c_0  
zlib                      1.2.11               h7b6447c_3

I searched for an issue in the Python bug tracker, but could not find anything.

Also, please allow me one remark on this:

a property should never be something that takes a lot of time to execute, otherwise it should probably be part of a function. It’s essentially a sign of bad code.

At least for our part (and probably also @natezb), this is not primarily about speed, but undesirable communication/code execution (in this case communication with hardware over the wire).

Properties are used to implement a simple (for the user) instrument interaction API, e.g. both setting and getting e.g. an instrument.voltage, while hiding away all the communication, value validation, and other details.

I sometimes use a sourcemeter instrument (think of it as a complicated power supply plus multimeter) with ~35 properties defined. Depending on the instrument state/configuration, not all are appropriate to run/query. I’ll have to check some time what exactly happens if I try to autocomplete on that one (see another demonstration in another package here). Yes, that could well become a speed issue on a serial connection, but I am more concerned about accidental side effects of code that was never intentionally run by the user, when all they wanted was to know what is available.

bilderbuchi on Jan 3, 2021

I am still seeing this issue with Jedi 0.15.1

dannygoldstein on Nov 26, 2019