So I have a command foo.py using Python 3 syntax in a directory on     my PATH.  It works fine, since Python 3.2.1 is in Python.file.      foo.py does not have a #! line.
    
    I can successfully execute:  foo.py
    
    However, the following fails:  py foo.py
    It fails, because foo.py is not found.  Instead, I have to specify:     py d:\path\to\foo.py
    This is annoying, py should walk the PATH for unqualified files (the     Windows PATH implicitly includes the current directory, of course,     but if it were in the current directory, it would just work).
    
    So when I: type c:\windows\system32\py.ini
    I get a set of h2 h3 v2 v3 commands in a section called [commands].      Not sure where my [defaults] went.  Is there some more Windows magic     to be explained?  WOW6432-ness, perhaps?  Probably my editor is     running as a 32-bit process, so looked in the wrong     C:\windows\system32 !!
    
    OK, with that mystery solved, and using Notepad running as     administrator to actually, successfully edit the file, it still runs     the wrong version of Python.  Here is the content of the file, what     is wrong?  And why is the spacing around the = in the [commands]     section so inconsistent?
    
    [defaults]
    python=3
    
    [commands]
    h2=c:\Python26\python -h
    h3 = c:\Python32\python -h
    v2= c:\Python26\python -V
    v3 =c:\Python32\python -V
    
    
    OK, so when I specify: py d:\path\to\foo.py
    It fails, but this time it is because it launches Python 2.6.4.  So     the [defaults] section doesn't seem to have an effect.
   ">

(original) (raw)

On 7/18/2011 6:41 PM, Vinay Sajip wrote: 
> So I can fix my machine, now that I understand what went wrong  
>  (delete py.exe entries from HCU, and put them in HLM instead).  
>  Then the other problem I have, is why py.exe launched py 2.6.4  
>  instead of py 3.2.1 when 3.2.1 is newer, and I don't have a #!  
>  line. That is probably the defined behavior of the launcher, to  
>  prefer 2.x if 3 isn't specified. I'll have to reread the launcher  
>  PEP. In my environment, I would much prefer to use 3.x if 2.x isn't  
>  specified... so hopefully when I reread the launcher PEP, I'll  
>  discover a way to do that. (I recall one can put -3 on the command  
>  line, so I could do that in the py.exe ftype commands, but hopefully  
>  there is a way to tweak the py.ini to do that.)  

Yes, the PEP explains what you need to do to get Python 3 to be the default:  
use the py.ini file or use an environment variable.


The use of py from the command line is merely a convenience for developers (as
the PEP says) - it's better to rely on shebang lines together with settings in
the .ini to get the behaviour you want.




OK, took a few minutes to play with the launcher again. I have
removed the HCU classes that point at the launcher, leaving me with
all my Python.File stuff pointing at some version of Python or
another. I seem to have Python 2.6.4, Python 3.1, and Python 3.2.1
installed, all 64-bit.



py.exe is located in c:\Windows\system32.exe, I modified the empty
py.ini that was installed to contain



Since I don't yet have associations set up that point at the
launcher, I thought I'd play with saying "py" in front of the
command.



So I have a command foo.py using Python 3 syntax in a directory on
my PATH. It works fine, since Python 3.2.1 is in Python.file.
foo.py does not have a #! line.



I can successfully execute: foo.py



However, the following fails: py foo.py

It fails, because foo.py is not found. Instead, I have to specify:
py d:\path\to\foo.py

This is annoying, py should walk the PATH for unqualified files (the
Windows PATH implicitly includes the current directory, of course,
but if it were in the current directory, it would just work).



So when I: type c:\windows\system32\py.ini

I get a set of h2 h3 v2 v3 commands in a section called [commands].
Not sure where my [defaults] went. Is there some more Windows magic
to be explained? WOW6432-ness, perhaps? Probably my editor is
running as a 32-bit process, so looked in the wrong
C:\windows\system32 !!



OK, with that mystery solved, and using Notepad running as
administrator to actually, successfully edit the file, it still runs
the wrong version of Python. Here is the content of the file, what
is wrong? And why is the spacing around the = in the [commands]
section so inconsistent?



[defaults]

python=3



[commands]

h2=c:\Python26\python -h

h3 = c:\Python32\python -h

v2= c:\Python26\python -V

v3 =c:\Python32\python -V





OK, so when I specify: py d:\path\to\foo.py

It fails, but this time it is because it launches Python 2.6.4. So
the [defaults] section doesn't seem to have an effect.