a trivial wrapper around pip on Windows that lets you overwrite the path to python.exe that gets hardcoded in launcher Scripts\<script>.exe files that pip creates via distlib.

⚠️ status: experimental

• (optional: rebuild the wrapper pip.exe: make)
• place the pip_wrapper dir somewhere on disk
• prepend the path to pip_wrapper\bin to the PATH env var (ensure it's positioned prior of any python installation path so it takes precedence over any other pip.exe on the system)

set env var MAKER_EXECUTABLE with the desired path to python.exe and run the wrapper pip.exe to install packages.

Example: Installing a relocatable* pip-sync.exe via pip:

(* relocatable = runs with whatever python.exe the PATH env var points to)

in a cmd.exe shell:

$ where pip
C:\pip_wrapper\bin\pip.exe
$ where python
c:\py3-7\python.exe
$ set MAKER_EXECUTABLE=python.exe
$ set destdir=c:\destdir
$ mkdir %destdir%
$ pip install pip-tools --prefix=%destdir%

to run the generated pip-sync.exe:

$ set PYTHONPATH=%destdir%\Lib\site-packages
$ %destdir%\Scripts\pip-sync.exe --version
pip-sync, version 6.0.1

it uses the python.exe found via the PATH env var. If we remove any Python install path from PATH it will stop working:

$ set PATH=c:\windows\system32;c:\windows
$ where python
INFO: Could not find files for the given pattern(s).
$ %destdir%\Scripts\pip-sync.exe --version
Fatal error in launcher: Unable to create process using '"python.exe"  "C:\destdir\Scripts\pip-sync.exe" --version': The system cannot find the file specified.

which means we could also run pip-sync.exe with any other python installation:

$ set PATH=c:\py3-9;%PATH%
$ where python
c:\py3-9\python.exe
$ %destdir%\pip-sync.exe --version
pip-sync, version 6.0.1

(Without this wrapper the pip-sync.exe would have to get rebuilt, i.e. by reinstalling the entire package, for this to work)