PyWin32 dependency could be optional for Fabric on Windows platform.

[diyan]

Hello devs,

I would like make Fabric less dependent on PyWin32 library on Windows platform.

There are only few places exists and looks like it it possible add additional checks for such cases.

It would be great if you have a time to look into this first small change.

I'm opened to any suggestions if they could help in pushing this changes into main upstream project.

Also I'm going to ask on one more pull requests in future.

[bitprophet]

Our use of Windows specific code has changed a few times over the years, so at this point I have no idea what is actually going to work on all Windows platforms. E.g. some assumptions made that work on "normal" Windows break for cygwin users, or breaks for Enthought users, or etc.

If you can take the time to double check the history of the files being modified / related issues here on github, to make sure your change will not break things for other users, that would be greatly appreciated. I can't test out Windows changes myself so I can only accept patches that are 99% sure not to break things :) Thanks!!

[diyan]

Hello Jeff,

As you asked, I have checked commit history back into 4 years of Fabric development in order to track how Windows-related code were changed.

You can see my changes in two functions - _rc_path and _get_system_username in state.py.

My change in _rc_path function in state.py file was based on implementation below...

fabric/fabric.py

Line 1178 in f7f402c

from win32com.shell.shell import SHGetSpecialFolderPath

...which was a little bit changed in commit below. This is was the last commit where implementation contains a change related to Windows platform, after that this portion of code was just moved around modules and functions during code refactoring.

fabric/fabric/subroutines.py

Line 52 in 4475717

def rc_path():

Commit below related to Python/Cygwin/Windows behavior...
diyan@b254048#L0R21

...and my change should not affect Python/Cygwin distribution because it always returns fabric.state.win32 == false:
http://docs.python.org/library/sys.html#sys.platform

Change in _get_system_username were maded on top of this implementation:

fabric/fabric.py

Line 49 in 4475717

if not win32:

I changed call pwd.getpwuid into getpass.getuser function which is supported on both Unix and Windows systems:
http://docs.python.org/library/getpass.html#getpass.getpass

Also I tried keep original implementation where possible.

You may see that for win32 cases there are exists fallback into original implementation:
https://github.com/diyan/fabric/blob/0a94630aaf4af6d6609aa858d6ffebf500c13d3a/fabric/state.py#L47
https://github.com/diyan/fabric/blob/0a94630aaf4af6d6609aa858d6ffebf500c13d3a/fabric/state.py#L61

Thank you for your feedback.

In case if you need anything else from me, please let me know.

[bitprophet]

Hi @diyan -- thanks so much for taking the time to look into that. Between your notes & the fact that your changes do look like they will fall back to the current implementation on failure, I think this is sufficient.

I'm not sure it's worth backporting to 1.3/1.4 (partly because those should be stable and this isn't a critical fix) but I will merge into master (1.5) in a moment.