The execution environment `ptipython` uses with the “-i” flag doesn’t appear as IPython’s

[fish2000]

I’ve produced a minimal example. Basically:

«develop»:PIPER-ECHO:clu[master •]$ cat /tmp/ipythonvariable.py 
try:
    __IPYTHON__
except NameError:
    IPYTHON = False
else:
    IPYTHON = True
«develop»:PIPER-ECHO:clu[master •]$ ptipython -i /tmp/ipythonvariable.py 
/usr/local/lib/python3.7/site-packages/IPython/core/interactiveshell.py:935: UserWarning: Attempting to work in a virtualenv. If you encounter problems, please install IPython inside the virtualenv.
  warn("Attempting to work in a virtualenv. If you encounter problems, please "
Python 3.7.6 (default, Dec 30 2019, 19:38:28) 
Type 'copyright', 'credits' or 'license' for more information
IPython 7.12.0 -- An enhanced Interactive Python. Type '?' for help.
In [1]: __IPYTHON__                                                                                  
Out[1]: True
In [2]: IPYTHON                                                                                      
Out[2]: False
In [3]: quit                                                                                         
«develop»:PIPER-ECHO:clu[master •]$ 

… in this case, the variable IPYTHON should evaluate to True, as it does when python -m IPython -i /tmp/ipythonvariable.py is run – because the special variable __IPYTHON__ is defined by IPython in the global namespace whenever it is running.

… It looks like ptpython runs the script named with “-i” before initializing the IPython environment, or somesuch – I briefly skimmed through the ptpython codebase but I’m not a REPL expert or an IPython guru or any of that, so this is just what I can surmise.

Either way it seems like a bug – the “-i” flag ought to behave as it does with vanilla IPython, n’est ce pas? I feel as though it ought. Yes.