pipx installed via pyapp complains pip isn't found

[yozachar]

Describe the bug

pipx complains no pip is available when installing poetry, or any other apps.

Steps to reproduce

$ asdf install pipx latest                                    
Requirement already satisfied: setuptools in ./.asdf/installs/pipx/1.2.0/venv/lib/python3.11/site-packages (65.5.0)
Collecting setuptools
  Using cached setuptools-67.7.2-py3-none-any.whl (1.1 MB)
Installing collected packages: setuptools
  Attempting uninstall: setuptools
    Found existing installation: setuptools 65.5.0
    Uninstalling setuptools-65.5.0:
      Successfully uninstalled setuptools-65.5.0
Successfully installed setuptools-67.7.2
Requirement already satisfied: pip in ./.asdf/installs/pipx/1.2.0/venv/lib/python3.11/site-packages (22.3.1)
Collecting pip
  Using cached pip-23.1.2-py3-none-any.whl (2.1 MB)
Collecting wheel
  Using cached wheel-0.40.0-py3-none-any.whl (64 kB)
Installing collected packages: wheel, pip
  Attempting uninstall: pip
    Found existing installation: pip 22.3.1
    Uninstalling pip-22.3.1:
      Successfully uninstalled pip-22.3.1
Successfully installed pip-23.1.2 wheel-0.40.0
Collecting pipx==1.2.0
  Using cached pipx-1.2.0-py3-none-any.whl (57 kB)
Collecting argcomplete>=1.9.4 (from pipx==1.2.0)
  Downloading argcomplete-3.0.8-py3-none-any.whl (40 kB)
     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 40.0/40.0 kB 1.7 MB/s eta 0:00:00
Collecting packaging>=20.0 (from pipx==1.2.0)
  Using cached packaging-23.1-py3-none-any.whl (48 kB)
Collecting userpath>=1.6.0 (from pipx==1.2.0)
  Using cached userpath-1.8.0-py3-none-any.whl (9.0 kB)
Collecting click (from userpath>=1.6.0->pipx==1.2.0)
  Using cached click-8.1.3-py3-none-any.whl (96 kB)
Installing collected packages: packaging, click, argcomplete, userpath, pipx
Successfully installed argcomplete-3.0.8 click-8.1.3 packaging-23.1 pipx-1.2.0 userpath-1.8.0
Collecting pipx==0.16.5
  Downloading pipx-0.16.5-py3-none-any.whl (54 kB)
     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 54.2/54.2 kB 2.8 MB/s eta 0:00:00
Collecting userpath>=1.6.0
  Using cached userpath-1.8.0-py3-none-any.whl (9.0 kB)
Collecting argcomplete<2.0,>=1.9.4
  Downloading argcomplete-1.12.3-py2.py3-none-any.whl (38 kB)
Collecting packaging>=20.0
  Using cached packaging-23.1-py3-none-any.whl (48 kB)
Collecting click
  Using cached click-8.1.3-py3-none-any.whl (96 kB)
Installing collected packages: argcomplete, packaging, click, userpath, pipx
Successfully installed argcomplete-1.12.3 click-8.1.3 packaging-23.1 pipx-0.16.5 userpath-1.8.0

$ pipx --version
1.2.0

$ pip --version      
pip 23.1.2 from /home/us-er/.asdf/installs/python/3.11.3/lib/python3.11/site-packages/pip (python 3.11)

$ pipx install poetry
Fatal error from pip prevented installation. Full pip output in file:
    /home/us-er/.local/pipx/logs/cmd_2023-05-04_15.15.45_pip_errors.log

Error installing poetry

$ cat /home/us-er/.local/pipx/logs/cmd_2023-05-04_15.15.45_pip_errors.log
PIP STDOUT
----------

PIP STDERR
----------
/home/us-er/.local/pipx/venvs/poetry/bin/python: No module named pip

Expected behavior

pipx works properly.

---

I'm aware that I can use pyapp directly, but I've reasons not to.

[yozachar]

Resolved pypa/pipx#974 (comment)