Can't print to stderr #23

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1. hayd commented on Jul 1, 2015

   

   hayd

   on Jul 1, 2015

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   It's unclear if the stderr part is

   Python/py-src/ltipy.py

   Line 222 in 134751c

   ipy = subprocess.Popen([cmd, 'kernel', '--pylab=inline'], stdout=subprocess.PIPE, stderr=subprocess.STDOUT, env=os.environ)

   or

   Python/py-src/ltipy.py

   Line 199 in 134751c

   next_line = ipy.stdout.readline().decode('utf-8')

   (those are my guesses).

   The print_function bug is different... scoping of exec?

   Edit: I can reproduce this locally:

   In [2]: exec(compile("from __future__ import print_function", "hello.py", 'exec'))
   
   In [3]: exec(compile("print('spam', file=sys.stderr)", "hello.py", 'exec'))
     File "hello.py", line 1
       print('spam', file=sys.stderr)
                         ^
   SyntaxError: invalid syntax
   
2. kenny-evitt

   added

   bug

   on Jul 14, 2015
3. dosmoc commented on Sep 7, 2015

   

   dosmoc

   on Sep 7, 2015

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   Had a look at the print_function bug. It appears to be related to the fact LightTable compiles each form in the file in sequence in py-src/ltmain.py:

     for form in toExec:
         code = form[1]
         loc = form[0]
         #conditional stuff for eval vs. exec
             code= compile(code, data[2]["name"], 'exec')

   and the fact that the print_function is a monkey patch to syntax that exists only at runtime.

   Attaching the from __future__ import print_function line to the code in py-src/ltmain.py allows something like print('spam', file=sys.stderr) to be evaluated successfully:

   if "print" in code:
     code = "from __future__ import print_function\n" + code
   
   code= compile(code, data[2]["name"], 'exec')

   I'm not familiar with Python/LightTable internals, so can't propose an actual solution.

   Edit: just realized that I've got an older version of the Python plugin installed, will need to check out the issue with the latest, but it looks like he basic problem remains the same.