Eryk Sun <[email protected]> added the comment:
The Popen() docs begin by explaining that it has "os.execvp()-like" behavior in
POSIX and uses CreateProcess() in Windows. Personally, I do not think it's
proper for Python's documentation to discuss details of how CreateProcess()
handles lpCommandLine (args), lpApplicationName (executable),
lpCurrentDirectory (cwd), and lpEnvironment (env). So maybe all this needs is
to clearly map Popen() parameters to the corresponding CreateProcess()
parameters.
If Popen() implements a parameter on its own, then it makes sense to me to
document the behavior. For example, in POSIX the behavior of `cwd` is
implemented by Popen(), and documented as follows:
In particular, the function looks for executable (or for the first
item in args) relative to cwd if the executable path is a relative
path.
This claim is not always true in POSIX since a base filename without a slash in
it, which is a relative path, is not searched for in the current directory
unless "." is in PATH. But the main problem with the above sentence is the lack
of a disclaimer that it only applies to POSIX. In Windows, `cwd` is passed
through directly as the lpCurrentDirectory of CreateProcess(). This parameter
sets the working directory of the child process and has nothing to do with
searching for an executable parsed out of lpCommandLine or resolving a relative
path in lpApplicationName. It may affect the result with shell=True, but even
in that case there are caveats. Regardless, Python doesn't do anything with
`cwd` in Windows except pass it to CreateProcess(), so the cwd ->
lpCurrentDirectory parameter mapping is all there is to document.
----------
status: languishing -> open
type: behavior -> enhancement
versions: +Python 3.10, Python 3.8, Python 3.9 -Python 2.7, Python 3.5, Python
3.6, Python 3.7
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<https://bugs.python.org/issue8557>
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