pipx behave different than pip if package already exists

2021-09-23T00:00:00+02:00

I decided to put as much as possible of my local config into an Ansible Playbook. Makes it easier to track what I install and change, also to setup from scratch should it necessary.

In the past I mainly used pip in combination with venv to install Python stuff. Changing for most of it to pipx seems logical, it will take care about the necessary venvs on it's own.

Just had to learn that the return code of pip is 0 but from pipx it's 1 in case a package already exists.

Why does it matter? Not the most elegant solution but I decided to just use command to trigger pip / pipx from my Playbook:

- name: Python Package Installation (pip)
  command: "python3 -m pip install --user {{ item }}"
  changed_when: false
  loop:
    - pipx
    - nox

- name: Python Package Installation (pipx)
  command: "pipx install {{ item }}"
  changed_when: false
  loop:
    - poetry
    - duplicity
    - pre-commit

No problem with pip, but pipx failed after the first run.

There was an older GitHub Issue, based on the comments, pipx was supposed to behave smilar as pip and also use return code 0 since v0.13 already. After some research I found the Pull Request that reverted the earlier change during some re-factoring.

Thanks to the great improvements in that PR, it was just a very small change necessary to restore the functionality introduced in Commit 11b853e:

diff --git a/docs/changelog.md b/docs/changelog.md
index 0a95ce15..67d14929 100644
--- a/docs/changelog.md
+++ b/docs/changelog.md
@@ -1,6 +1,7 @@
 dev

 - Fixed `pipx list` output phrasing to convey that python version displayed is the one with which package was installed.
+- Fixed `pipx install` to provide return code 0 if venv already exists, similar to pip’s behavior. (#736)

 0.16.4

diff --git a/src/pipx/constants.py b/src/pipx/constants.py
index 4fe2d58b..11fc013f 100644
--- a/src/pipx/constants.py
+++ b/src/pipx/constants.py
@@ -21,7 +21,7 @@
 # pipx shell exit codes
 EXIT_CODE_OK = ExitCode(0)
 EXIT_CODE_INJECT_ERROR = ExitCode(1)
-EXIT_CODE_INSTALL_VENV_EXISTS = ExitCode(1)
+EXIT_CODE_INSTALL_VENV_EXISTS = ExitCode(0)
 EXIT_CODE_LIST_PROBLEM = ExitCode(1)
 EXIT_CODE_UNINSTALL_VENV_NONEXISTENT = ExitCode(1)
 EXIT_CODE_UNINSTALL_ERROR = ExitCode(1)
diff --git a/tests/test_install.py b/tests/test_install.py
index 941f4c01..0eb2d9cc 100644
--- a/tests/test_install.py
+++ b/tests/test_install.py
@@ -109,7 +109,7 @@ def test_install_no_packages_found(pipx_temp_env, capsys):

 def test_install_same_package_twice_no_force(pipx_temp_env, capsys):
     assert not run_pipx_cli(["install", "pycowsay"])
-    assert run_pipx_cli(["install", "pycowsay"])
+    assert not run_pipx_cli(["install", "pycowsay"])
     captured = capsys.readouterr()
     assert (
         "'pycowsay' already seems to be installed. Not modifying existing installation"

Related Pull Request: https://github.com/pypa/pipx/pull/736

Merged into pipx/main on 25th September 2021

That's a good example why I love and prefer Open Source, I could fix the Problem on my own and share the improvement with the community, within a few days it was already merged and will be part of the next Release.

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pipx behave different than pip if package already exists