function to find the modification date of the project

[Joe Strout]

This isn't a question, but something I thought others may find useful 
(and if somebody can spot any errors with it, I'll be grateful).

We had a case recently where the client was running an older version of 
our app, and didn't realize it.  In other languages I've avoided this by 
displaying the compile date in the About box, but of course Python 
doesn't really have a meaningful compile date.  So, instead we're now 
displaying the latest modification date of any .py file in the project. 
  Here's the function that finds that:


def lastModDate():
     "Get the latest modification date (as a string) of any .py file in 
this project."
     import os, time
     latest = 0
     dir = os.path.dirname(__file__)
     if dir == '': dir = '.'  # HACK, but appears necessary
     for fname in os.listdir(dir):
         if fname.endswith('.py'):
             modtime = os.stat(os.path.join(dir, fname)).st_mtime
             if modtime > latest: latest = modtime
     out = time.strftime('%Y-%m-%d', time.localtime(latest))
     return out


The intent of this code is to find any .py files in the same directory 
as the module containing the above code, and return (as a date string in 
SQL/ISO format) the latest modification date thereof.  Then, this is 
displayed to the user in the about box like so:

         dlg = wx.MessageDialog(self,
               "etown unified database system\nRevision: %s" \
               % lastModDate(),
               "About etown Central", wx.OK | wx.ICON_INFORMATION)
         dlg.ShowModal()
         dlg.Destroy()

(That's wxPython, of course.)

I haven't yet tested this in a packaged app or on Windows, but it seems 
to work in our OS X test environment.

One odd thing was the need to employ the HACK identified above, where if 
__file__ happens to already be in the current directory, then 
os.path.dirname of it returns the empty-string -- yet the empty-string 
is not a valid argument to os.listdir().  Is there a better way to a 
list of files in the same directory as a given file?

Cheers,
- Joe