Make Pip detect Pip/Python mismatch

[petersuter]

I don’t think merging the paths would not even help much.

A simple scenario:
Install Python 3.X. Add it to PATH.
Install Python 3.X-1. Add it to PATH.
pip probably refers to 3.X-1 because it was added to PATH last.
py probably refers to 3.X because it prefers the latest version.

@kknechtel

I thought the installer adds both paths to PATH when the option is checked.

Probably not everyone uses that. Nothing enforces them to remain in sync. The order of the paths in PATH also matters.

Some more (complex) reasons for a mismatch are mentioned here:

Could we add Python to system PATH by default?

The 3.7 app distribution may take precedence over PATH when running “python” or “pythonw” using the shell execute family of functions and COM interfaces, or when getting a command line to run “python” by way of SHEvaluateSystemCommandTemplate. These API functions prefer registered application names in the system (but not user) “App Paths” key over searching PATH. A searched name either has to literally match a registered name or has to have no extension and match with “.EXE” appended (*). Shel…