'Execute in external system terminal' unwantedly uses python2 on ubuntu16.04

[cknoll]

Description of your problem

What steps will reproduce the problem?

The simple script

import sys
print(sys.version)

What is the expected output? What do you see instead?

It produces different results, depending on run-configuration
option 1 "Execute in current console" and 2 "... dedicated console" results in output 3.5.2
case 3 "Excecute in external system terminal" results in output 2.17.12

Please provide any additional information below

I think the problem might be related to this line
https://github.com/spyder-ide/spyder/blob/master/spyder/utils/programs.py#L268

p_args = ['python']

My suggestion instead:

if PY2:
    p_args = ['python2']
 else:
    p_args = ['python3']

Note that python runs python2 by default on Ubuntu16.04 and Debian9 (and I suppose at least the earlier versions)

Versions and main components

• Spyder Version: 3.2.2
• Python Version: 3.5.2
• Qt Version: 4.8.7
• PyQt Version: 4.11.4
• Operating system: Ubuntu 16.04.

Dependencies

IPython >=4.0 : 6.1.0 (OK)
cython >=0.21 : None (NOK)
jedi >=0.9.0 : 0.10.2 (OK)
nbconvert >=4.0 : 5.3.1 (OK)
numpy >=1.7 : 1.11.0 (OK)
pandas >=0.13.1 : 0.17.1 (OK)
psutil >=0.3 : 5.3.0 (OK)
pycodestyle >=2.3: 2.3.1 (OK)
pyflakes >=0.6.0 : 1.6.0 (OK)
pygments >=2.0 : 2.2.0 (OK)
pylint >=0.25 : 1.7.2 (OK)
qtconsole >=4.2.0: 4.3.1 (OK)
rope >=0.9.4 : 0.10.7 (OK)
sphinx >=0.6.6 : 1.6.3 (OK)
sympy >=0.7.3 : 0.7.6.1 (OK)

[ccordoba12]

My suggestion instead:

if PY2:
    p_args = ['python2']
else:
    p_args = ['python3']

Your suggestion is the right one, but it should be applied only to Linux.

If you want to see this in our next release, please open a pull request with your suggestion against the 3.x branch. Else, it's going to take us some time to fix this because it's low priority.

[jitseniesen]

Alternatively, we could use get_python_executable() from https://github.com/spyder-ide/spyder/blob/master/spyder/utils/misc.py#L173 , which (I think) uses the same executable that Spyder is run with.

[ccordoba12]

Yep, that's a better suggestion. Thanks @jitseniesen!

[cknoll]

I opened a PR (#5181). I would like to see this merged asap, because I will use spyder in a Python-for-engineering-lecture and running scripts in external terminals is necessary for some of the content.
(But of course: The project has its own priorities... )