2.4->2.5 current directory change?

[Ziga Seilnacht]

On Feb 26, 7:44 pm, "Chris Mellon" <arka... at gmail.com> wrote:
> This appears to be a change in behavior from Python 2.4 to Python 2.5,
> which I can't find documented anywhere. It may be windows only, or
> related to Windows behavior.
>
> In 2.4, the current directory (os.curdir) was on sys.path. In 2.5, it
> appears to be the base directory of the running script. For example,
> if you execute the file testme.py in your current working directory,
> '' is on sys.path. If you execute c:\Python25\Scripts\testme.py, '' is
> *not* on sys.path, and C:\Python25\Scripts is.
>
> That means if you run a Python script located in another directory,
> modules/etc in your current working directory will not be found. This
> makes .py scripts in the PYTHONHOME\Scripts file moderately useless,
> because they won't find anything in the current working directory.
>
> I first noticed this because it breaks Trial, but I'm sure there are
> other scripts affected by it. Is this desirable behavior? Is there
> anything to work around it except by pushing os.curdir onto sys.path?


The change was intentional and is mentioned in the NEWS file:

- Patch #1232023: Stop including current directory in search path
  on Windows.

This unifies Python's behaviour across different platforms; the
docs always said that the current directory is inserted *only*
if the script directory is unavailable:

    As initialized upon program startup, the first item of this list,
    path[0], is the directory containing the script that was used to
    invoke the Python interpreter. If the script directory is not
    available (e.g. if the interpreter is invoked interactively or
    if the script is read from standard input), path[0] is the empty
    string, which directs Python to search modules in the current
    directory first. Notice that the script directory is inserted
    before the entries inserted as a result of PYTHONPATH.

The old behaviour was never intentional and wasn't desired,
because users could break an application simply by running it
from a directory that contained inappropriately named files.

For details see the bug report and patch submission:
http://www.python.org/sf/1526785
http://www.python.org/sf/1232023

Ziga