New submission from Erik Bray:
This actually came up previously in #1543469 in the context of test_subprocess,
but it's a more general issue that I thought was worth addressing somehow.
The issue here is that as Cygwin tries to provide a "UNIX-like" experience, any
system interfaces that take the path to an executable as an argument allow the
.exe extension to be left off. This is particularly convenient for the shell
experience, so that one can run, for example "python" or "ls" without typing
"python.exe" or "ls.exe" (this is of course true of the Windows cmd shell as
In the case of ambiguity however--such as when there is both a "python" and a
"python.exe" in the same path, one must explicitly add the ".exe", otherwise
the path without the exe is assumed. This is made even worse when you factor
Thus, this becomes a real annoyance when developing Python on Cygwin because
you get both a "python.exe" and the "Python" directory in your source tree.
This isn't so much of a problem, except that sys.executable leaves off the
".exe" (in UNIX-y fashion), so any test that calls Popen([sys.executable])
errors out because it thinks you're trying to execute a directory (Python/).
I think the only reasonable fix is to take the patch suggested at #1543469, and
ensure that the ".exe" suffix is appended to sys.executable on Cygwin. I think
that sys.executable should be as unambiguous as possible, and that's the only
way to make it reasonably unambiguous on Cygwin.
I've attached a patch adapted from the one in #1543469 which solves the issue
keywords: needs review, patch
nosy: erik.bray, masamoto, zach.ware
title: sys.executable is ambiguous on Cygwin without .exe suffix
versions: Python 3.7
Added file: http://bugs.python.org/file45091/cygwin-sys-executable.patch
Python tracker <rep...@bugs.python.org>
Python-bugs-list mailing list