Stop installing setuptools and wheel on Python 3.12+

Currently `get-pip.py` installs not only pip, but also setuptools and
wheel by default, unless the `--no-setuptools` / `--no-wheel` (or
`PIP_NO_SETUPTOOLS` / `PIP_NO_WHEEL` env vars) are used.

This has historically been necessary, however, modern versions of pip
will now fallback to `pyproject.toml` (PEP 517: [1]) based builds (which
will default to a setuptools backend, and thus automatically install
setuptools and wheel in the isolated build environment) if either
setuptools is not installed (as of pip 22.1: [2]), or if wheel is not
installed (as of pip 23.1: [3]).

In addition, as of Python 3.12, the stdlib's `ensurepip` and `venv`
modules no longer install setuptools, and only install pip ([4]).

As such, it is now time for `get-pip.py` to stop installing setuptools
and wheel by default on Python 3.12+, in order to:
- Act as another small step towards `pyproject.toml` / PEP 517
  based builds eventually becoming the pip default.
- Improve parity with the behaviour of `ensurepip` / `venv` on
  Python 3.12+.
- Allow `get-pip.py` to focus on its primary responsibility:
  bootstrapping Pip.

Closes pypa#200.

[1]: https://peps.python.org/pep-0517/
[2]: pypa/pip#10717
[3]: pypa/pip#11871
[4]: python/cpython#101039

Author: edmorley

README.md

@@ -1,7 +1,7 @@
 # get-pip.py
 
-`get-pip.py` is a bootstrapping script that enables users to install pip,
-setuptools, and wheel in Python environments that don't already have them. You
+`get-pip.py` is a bootstrapping script that enables users to install pip
+in Python environments that don't already have it installed. You
 should not directly reference the files located in this repository and instead
 use the versions located at <https://bootstrap.pypa.io/>.
 
@@ -12,26 +12,34 @@ $ curl -sSL https://bootstrap.pypa.io/get-pip.py -o get-pip.py
 $ python get-pip.py
 ```
 
-Upon execution, `get-pip.py` will install `pip`, `setuptools` and `wheel` in
-the current Python environment.
+Upon execution, `get-pip.py` will install the latest version of `pip` into the
+current Python environment. When using Python 3.11 or older, by default the
+packages `setuptools` and `wheel` will also be installed if an existing version
+of them was not found.
 
 It is possible to provide additional arguments to the underlying script. These
 are passed through to the underlying `pip install` command, and can thus be
-used to constraint the versions of the packages, or to pass other pip options
-such as `--no-index`.
+used to constrain the versions of the packages, install additional packages,
+or to pass other pip options such as `--no-index`.
 
 ```console
-$ python get-pip.py "pip < 21.0" "setuptools < 50.0" "wheel < 1.0"
+# Constrain the pip version
+$ python get-pip.py "pip < 21.0"
+
+# Force the installation of `setuptools` and `wheel` on newer Python versions.
+$ python get-pip.py setuptools wheel
+
+# Install packages from a local directory instead of PyPI.
 $ python get-pip.py --no-index --find-links=/local/copies
 ```
 
 ### get-pip.py options
 
-This script also has it's own options, which control which packages it will
+This script also has its own options, which control which packages it will
 install.
 
-- `--no-setuptools`: do not attempt to install `setuptools`.
-- `--no-wheel`: do not attempt to install `wheel`.
+- `--no-setuptools`: Do not attempt to install `setuptools`. This is a no-op on Python 3.12+.
+- `--no-wheel`: Do not attempt to install `wheel`. This is a no-op on Python 3.12+.
 
 ## Development
 

public/3.6/get-pip.py

@@ -45,22 +45,24 @@
 
 def include_setuptools(args):
     """
-    Install setuptools only if absent and not excluded.
+    Install setuptools only if absent, not excluded and when using Python <3.12.
     """
     cli = not args.no_setuptools
     env = not os.environ.get("PIP_NO_SETUPTOOLS")
     absent = not importlib.util.find_spec("setuptools")
-    return cli and env and absent
+    python_lt_3_12 = this_python < (3, 12)
+    return cli and env and absent and python_lt_3_12
 
 
 def include_wheel(args):
     """
-    Install wheel only if absent and not excluded.
+    Install wheel only if absent, not excluded and when using Python <3.12.
     """
     cli = not args.no_wheel
     env = not os.environ.get("PIP_NO_WHEEL")
     absent = not importlib.util.find_spec("wheel")
-    return cli and env and absent
+    python_lt_3_12 = this_python < (3, 12)
+    return cli and env and absent and python_lt_3_12
 
 
 def determine_pip_install_arguments():
@@ -111,7 +113,7 @@ def bootstrap(tmpdir):
     monkeypatch_for_cert(tmpdir)
 
     # Execute the included pip and use it to install the latest pip and
-    # setuptools from PyPI
+    # any user-requested packages from PyPI.
     from pip._internal.cli.main import main as pip_entry_point
     args = determine_pip_install_arguments()
     sys.exit(pip_entry_point(args))

public/3.7/get-pip.py

@@ -45,22 +45,24 @@
 
 def include_setuptools(args):
     """
-    Install setuptools only if absent and not excluded.
+    Install setuptools only if absent, not excluded and when using Python <3.12.
     """
     cli = not args.no_setuptools
     env = not os.environ.get("PIP_NO_SETUPTOOLS")
     absent = not importlib.util.find_spec("setuptools")
-    return cli and env and absent
+    python_lt_3_12 = this_python < (3, 12)
+    return cli and env and absent and python_lt_3_12
 
 
 def include_wheel(args):
     """
-    Install wheel only if absent and not excluded.
+    Install wheel only if absent, not excluded and when using Python <3.12.
     """
     cli = not args.no_wheel
     env = not os.environ.get("PIP_NO_WHEEL")
     absent = not importlib.util.find_spec("wheel")
-    return cli and env and absent
+    python_lt_3_12 = this_python < (3, 12)
+    return cli and env and absent and python_lt_3_12
 
 
 def determine_pip_install_arguments():
@@ -111,7 +113,7 @@ def bootstrap(tmpdir):
     monkeypatch_for_cert(tmpdir)
 
     # Execute the included pip and use it to install the latest pip and
-    # setuptools from PyPI
+    # any user-requested packages from PyPI.
     from pip._internal.cli.main import main as pip_entry_point
     args = determine_pip_install_arguments()
     sys.exit(pip_entry_point(args))

public/get-pip.py

@@ -45,22 +45,24 @@
 
 def include_setuptools(args):
     """
-    Install setuptools only if absent and not excluded.
+    Install setuptools only if absent, not excluded and when using Python <3.12.
     """
     cli = not args.no_setuptools
     env = not os.environ.get("PIP_NO_SETUPTOOLS")
     absent = not importlib.util.find_spec("setuptools")
-    return cli and env and absent
+    python_lt_3_12 = this_python < (3, 12)
+    return cli and env and absent and python_lt_3_12
 
 
 def include_wheel(args):
     """
-    Install wheel only if absent and not excluded.
+    Install wheel only if absent, not excluded and when using Python <3.12.
     """
     cli = not args.no_wheel
     env = not os.environ.get("PIP_NO_WHEEL")
     absent = not importlib.util.find_spec("wheel")
-    return cli and env and absent
+    python_lt_3_12 = this_python < (3, 12)
+    return cli and env and absent and python_lt_3_12
 
 
 def determine_pip_install_arguments():
@@ -111,7 +113,7 @@ def bootstrap(tmpdir):
     monkeypatch_for_cert(tmpdir)
 
     # Execute the included pip and use it to install the latest pip and
-    # setuptools from PyPI
+    # any user-requested packages from PyPI.
     from pip._internal.cli.main import main as pip_entry_point
     args = determine_pip_install_arguments()
     sys.exit(pip_entry_point(args))

templates/default.py

@@ -45,22 +45,24 @@
 
 def include_setuptools(args):
     """
-    Install setuptools only if absent and not excluded.
+    Install setuptools only if absent, not excluded and when using Python <3.12.
     """
     cli = not args.no_setuptools
     env = not os.environ.get("PIP_NO_SETUPTOOLS")
     absent = not importlib.util.find_spec("setuptools")
-    return cli and env and absent
+    python_lt_3_12 = this_python < (3, 12)
+    return cli and env and absent and python_lt_3_12
 
 
 def include_wheel(args):
     """
-    Install wheel only if absent and not excluded.
+    Install wheel only if absent, not excluded and when using Python <3.12.
     """
     cli = not args.no_wheel
     env = not os.environ.get("PIP_NO_WHEEL")
     absent = not importlib.util.find_spec("wheel")
-    return cli and env and absent
+    python_lt_3_12 = this_python < (3, 12)
+    return cli and env and absent and python_lt_3_12
 
 
 def determine_pip_install_arguments():
@@ -111,7 +113,7 @@ def bootstrap(tmpdir):
     monkeypatch_for_cert(tmpdir)
 
     # Execute the included pip and use it to install the latest pip and
-    # setuptools from PyPI
+    # any user-requested packages from PyPI.
     from pip._internal.cli.main import main as pip_entry_point
     args = determine_pip_install_arguments()
     sys.exit(pip_entry_point(args))