Merge #594 feat: Nvim can detect venv python via "pynvim-python" tool

Author: justinmk

README.md

@@ -12,17 +12,35 @@ Install
 
 Supports python 3.7 or later.
 
-    pip3 install pynvim
+- Installation option #1: install using uv (recommended):
 
-You can install the package without being root by adding the `--user` flag.
-Anytime you upgrade Neovim, make sure to upgrade pynvim as well:
+  - Install uv (https://docs.astral.sh/uv/).
 
-    pip3 install --upgrade pynvim
+  - Install pynvim (the `--upgrade` switch ensures installation of the latest
+    version):
 
-Alternatively, you can install the development version by cloning this
-repository and executing the following at the top level:
+        uv tool install --upgrade pynvim
 
-    pip3 install .
+  - Anytime you upgrade Neovim, make sure to upgrade pynvim as well by
+    re-running the above command.
+
+- Installation option #2: install using pipx:
+
+  - Install pipx (https://pipx.pypa.io/stable/).
+
+  - Install pynvim (the `--upgrade` switch ensures installation of the latest
+    version):
+
+        pipx install --upgrade pynvim
+
+  - Anytime you upgrade Neovim, make sure to upgrade pynvim as well by
+    re-running the above command.
+
+- Other installation options:
+
+  - See [pynvim installation
+    documentation](https://pynvim.readthedocs.io/en/latest/installation.html)
+    for additional installation options and information.
 
 Python Plugin API
 -----------------

docs/installation.rst

@@ -3,17 +3,63 @@ Installation
 
 The Neovim Python client supports Python 3.7 or later.
 
-Using pip
----------
+Using uv or pipx
+----------------
 
-You can install the package without being root by adding the ``--user`` flag::
+For automatic detection by Neovim, pynvim should be installed in a dedicated
+Python virtual environment and the ``pynvim-python`` executable should be placed
+on the ``PATH``.  The recommended approach for this is to use a tool like uv
+(https://docs.astral.sh/uv/) or pipx (https://pipx.pypa.io/stable/); the
+``--upgrade`` switch ensures installation of the latest version:
 
-    pip3 install --user pynvim
+- Install using uv (recommended)::
 
-If you follow Neovim HEAD, make sure to upgrade ``pynvim`` when you upgrade
-Neovim::
+    uv tool install --upgrade pynvim
 
-    pip3 install --upgrade pynvim
+- Install using pipx::
+
+    pipx install --upgrade pynvim
+
+**NOTE** For Neovim before v0.12.0, set the variable ``python3_host_prog`` in
+``init.vim`` to point to ``pynvim-python``::
+
+    let g:python3_host_prog = 'pynvim-python'
+
+Using manually created Python virtual environment
+-------------------------------------------------
+
+Alternatively, you may manually create a Python virtual environment
+(https://docs.python.org/3.13/library/venv.html)::
+
+    python3 -m venv pynvim-venv
+
+Then install pynvim into the virtual environment; the
+``--upgrade`` switch ensures installation of the latest version::
+
+- For Unix::
+
+    pynvim-venv/bin/python -m pip install --upgrade pynvim
+
+- For Windows::
+
+    pynvim-venv\Scripts\python -m pip install --upgrade pynvim
+
+Then copy the ``pynvim-python`` executable somewhere on the ``PATH``:
+
+- For Unix::
+
+    # Assuming `~/.local/bin` is on `PATH`:
+    cp pynvim-venv/bin/pynvim-python ~/.local/bin/pynvim-python
+
+- For Windows::
+
+    REM Assuming `C:\apps` is on `PATH`:
+    copy pynvim-venv\Scripts\pynvim-python.exe C:\apps\pynvim-python.exe
+
+**NOTE** For Neovim before v0.12.0, set the variable ``python3_host_prog`` in
+``init.vim`` to point to ``pynvim-python``::
+
+    let g:python3_host_prog = 'pynvim-python'
 
 Install from source
 -------------------
@@ -23,6 +69,70 @@ Clone the repository somewhere on your disk and enter to the repository::
     git clone https://github.com/neovim/pynvim.git
     cd pynvim
 
-Now you can install it on your system::
+Now you can install it following the instructions above, using ``.`` instead of
+``pynvim``; the ``--upgrade`` switch ensures installation of the latest version:
+
+- Install from source using uv::
+
+    uv tool install --upgrade .
+
+- Install from source using pipx::
+
+    pipx install --upgrade .
+
+- Install from source using manually created Python virtual environment:
+
+  - Create ``pynvim-venv`` as above.
+
+  - Install:
+
+    - For Unix::
+
+        pynvim-venv/bin/python -m pip install --upgrade .
+
+    - For Windows::
+
+        pynvim-venv\Scripts\python -m pip install --upgrade .
+
+  - Copy ``pynvim-python`` executable as above.
+
+**NOTE** For Neovim before v0.12.0, set the variable ``python3_host_prog`` in
+``init.vim`` to point to ``pynvim-python``::
+
+    let g:python3_host_prog = 'pynvim-python'
+
+Upgrade pynvim when upgrading Neovim
+------------------------------------
+
+Make sure to upgrade ``pynvim`` when you upgrade Neovim.  Follow the previous
+instructions; the ``--upgrade`` switch will ensure installation of the latest
+version.
+
+Explicitly choosing pynvim virtual environment
+----------------------------------------------
+
+As an alternative to exposing ``pynvim-python`` on ``PATH``, you may configure
+Neovim to use a specific Python interpreter that has pynvim installed; this may
+be useful when working on pynvim itself.
+
+After installing into a virtual environment named ``pynvim-venv``, add the
+following into Neovim's ``init.vim`` file:
+
+- For Unix::
+
+      let g:python3_host_prog = '/path/to/pynvim-venv/bin/python'
+
+- For Windows::
+
+      let g:python3_host_prog = 'c:\path\to\pynvim-venv\bin\python.exe'
+
+Installing outside of a virtual environment is deprecated
+---------------------------------------------------------
+
+Installing into the per-user Python site package area is a deprecated practice
+with recent Python versions.  For example, the following command fails on Ubuntu
+24.04 with the error message ``error: externally-managed-environment``::
+
+    pip install --user pynvim
 
-    pip3 install .
+Instead, always install into a virtual environment.

pynvim/python.py

@@ -0,0 +1,28 @@
+"""Wrapper to expose the Python interpreter as `pynvim-python`.
+
+`setup.py` declares an entry point for the `main()` function below. When
+`pynvim` is installed, an executable named `pynvim-python` will be generated
+that will invoke `main()` below; that function then simply chains to the
+underlying Python interpreter, passing along all command-line arguments.
+
+The intent is to have `pynvim-python` be on the `PATH` such that an invocation
+such as:
+
+    pynvim-python -c 'import pynvim'
+
+is equivalent to explicitly running the correct Python interpreter where
+`pynvim` is installed:
+
+    /path/to/python -c 'import pynvim'
+
+This allows Neovim to automatically detect the correct Python interpreter for
+use with `pynvim`.
+"""
+
+import subprocess
+import sys
+
+
+def main() -> None:
+    """Chain to Python interpreter, passing all command-line args."""
+    subprocess.run([sys.executable] + sys.argv[1:])

setup.py

@@ -58,4 +58,9 @@
       setup_requires=setup_requires,
       tests_require=tests_require,
       extras_require=extras_require,
+      entry_points={
+              'console_scripts': [
+                  'pynvim-python=pynvim.python:main',
+              ],
+          },
       )

test/test_window.py

@@ -61,10 +61,11 @@ def test_vars(vim: Nvim) -> None:
 def test_options(vim: Nvim) -> None:
     vim.current.window.options['colorcolumn'] = '4,3'
     assert vim.current.window.options['colorcolumn'] == '4,3'
+    old_global_statusline = vim.options['statusline']
     # global-local option
     vim.current.window.options['statusline'] = 'window-status'
     assert vim.current.window.options['statusline'] == 'window-status'
-    assert vim.options['statusline'] == ''
+    assert vim.options['statusline'] == old_global_statusline
 
     with pytest.raises(KeyError) as excinfo:
         vim.current.window.options['doesnotexist']