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Minor changes to PEP453 for grammar and content

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Donald Stufft 2013-09-19 09:22:19 -04:00
parent 70aa3a1a6b
commit 9d355e6f73
1 changed files with 32 additions and 28 deletions
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pep-0453.txt
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@ -17,8 +17,8 @@ Abstract
This PEP proposes that the `pip`_ package manager be made available by This PEP proposes that the `pip`_ package manager be made available by
default when installing CPython and when creating virtual environments default when installing CPython and when creating virtual environments
using the standard library's ``venv`` module (including via the using the standard library's ``venv`` module via the ``pyvenv`` command line
``pyvenv`` command line utility). utility).
To clearly demarcate development responsibilities, and to avoid To clearly demarcate development responsibilities, and to avoid
inadvertently downgrading ``pip`` when updating CPython, the proposed inadvertently downgrading ``pip`` when updating CPython, the proposed
@ -64,12 +64,12 @@ it, and how to install it. The effect of this is that third-party Python
projects are currently required to choose from a variety of undesirable projects are currently required to choose from a variety of undesirable
alternatives: alternatives:
* assume the user already has a suitable cross-platform package manager * Assume the user already has a suitable cross-platform package manager
installed installed.
* duplicate the instructions and tell their users how to install the * Duplicate the instructions and tell their users how to install the
package manager package manager.
* completely forgo the use of dependencies to ease installation concerns * Completely forgo the use of dependencies to ease installation concerns
for their users for their users.
All of these available options have significant drawbacks. All of these available options have significant drawbacks.
@ -79,7 +79,7 @@ doesn't work. Some operating systems may ease this pain by providing a
global hook that looks for commands that don't exist and suggest an OS global hook that looks for commands that don't exist and suggest an OS
package they can install to make the command work, but that only works package they can install to make the command work, but that only works
on systems with platform package managers (such as major Linux on systems with platform package managers (such as major Linux
distributions). No such assistance is availabe for Windows and distributions). No such assistance is available for Windows and
Mac OS X users. The challenges of dealing with this problem are a Mac OS X users. The challenges of dealing with this problem are a
regular feature of feedback the core Python developers receive from regular feature of feedback the core Python developers receive from
professional educators and others introducing new users to Python. professional educators and others introducing new users to Python.
@ -154,7 +154,7 @@ for a tool bundled with CPython.
Other tools like ``zc.buildout`` and ``conda`` are more ambitious in their Other tools like ``zc.buildout`` and ``conda`` are more ambitious in their
aims (and hence substantially better than ``pip`` at handling external aims (and hence substantially better than ``pip`` at handling external
binary dependencies), so it makes sense for the Python ecosystem to treat binary dependencies), so it makes sense for the Python ecosystem to treat
them more like platform package managers to interoperate with rather than them more like platform package managers to inter operate with rather than
as the default cross-platform installation tool. This relationship is as the default cross-platform installation tool. This relationship is
similar to that between ``pip`` and platform package management systems similar to that between ``pip`` and platform package management systems
like ``apt`` and ``yum`` (which are also designed to handle arbitrary like ``apt`` and ``yum`` (which are also designed to handle arbitrary
@ -210,7 +210,7 @@ Implementation strategy
To ensure there is no need for network access when installing Python or To ensure there is no need for network access when installing Python or
creating virtual environments, the ``extractpip`` module will, as an creating virtual environments, the ``extractpip`` module will, as an
implementation detail, include a complete private copy of pip and its implementation detail, include a complete private copy of pip and its
dependencies which will be used to extra pip and install it into the target dependencies which will be used to extract pip and install it into the target
environment. It is important to stress that this private copy of pip is environment. It is important to stress that this private copy of pip is
*only* an implementation detail and it should *not* be relied on or *only* an implementation detail and it should *not* be relied on or
assumed to exist beyond the public capabilities exposed through the assumed to exist beyond the public capabilities exposed through the
@ -225,7 +225,7 @@ to include private copies of ``pip`` and ``setuptools`` as wheel files
contact PyPI (instead installing directly from the private wheel files. contact PyPI (instead installing directly from the private wheel files.
Rather than including separate code to handle the bootstrapping, the Rather than including separate code to handle the bootstrapping, the
``extractpip`` module will manipulating sys.path appropriately to allow ``extractpip`` module will manipulate sys.path appropriately to allow
the wheel files to be used to install themselves, either into the current the wheel files to be used to install themselves, either into the current
Python installation or into a virtual environment (as determined by the Python installation or into a virtual environment (as determined by the
options passed to the bootstrap command). options passed to the bootstrap command).
@ -267,11 +267,15 @@ The proposed ``extractpip`` module API consists of the following two
functions:: functions::
def version(): def version():
"""Returns a string specifying the bootstrapped version of pip""" """
Returns a string specifying the bundled version of pip.
"""
def bootstrap(root=None, upgrade=False, user=False, verbosity=0): def bootstrap(root=None, upgrade=False, user=False, verbosity=0):
"""Bootstrap pip into the current Python installation (or the given """
root directory)""" Bootstrap pip into the current Python installation (or the given root
directory).
"""
Invocation from the CPython installers Invocation from the CPython installers
@ -390,7 +394,7 @@ This PEP proposes that, if pip still requires it as a dependency,
to the private copy of ``extractpip``). ``python -m extractpip`` will then to the private copy of ``extractpip``). ``python -m extractpip`` will then
install the private copy in addition to installing ``pip`` itself. install the private copy in addition to installing ``pip`` itself.
However, this behaviour is officially considered an implementation However, this behavior is officially considered an implementation
detail. Other projects which explicitly require ``setuptools`` must still detail. Other projects which explicitly require ``setuptools`` must still
provide an appropriate dependency declaration, rather than assuming provide an appropriate dependency declaration, rather than assuming
``setuptools`` will always be installed alongside ``pip``. ``setuptools`` will always be installed alongside ``pip``.
@ -500,10 +504,10 @@ above.
Adding the scripts directory to the system PATH would mean that ``pip`` Adding the scripts directory to the system PATH would mean that ``pip``
works reliably in the "only one Python installation on the system PATH" works reliably in the "only one Python installation on the system PATH"
case, with ``py -m pip`` needed only to select a non-default version in case, with ``py -m pip``, ``pipX``, or ``pipX.Y`` needed only to select a
the parallel installation case (and outside a virtual environment). This non-default version in the parallel installation case (and outside a virtual
change should also make the ``pyvenv`` command substantially easier to environment). This change should also make the ``pyvenv`` command substantially
invoke on Windows, along with all scripts installed by ``pip``, easier to invoke on Windows, along with all scripts installed by ``pip``,
``easy_install`` and similar tools. ``easy_install`` and similar tools.
While the script invocations on recent versions of Python will run through While the script invocations on recent versions of Python will run through
@ -531,8 +535,8 @@ downstream distributors:
* Do not remove the bundled copy of pip. * Do not remove the bundled copy of pip.
* This is required for offline installation of pip into a virtual * This is required for installation of pip into a virtual environment by the
environment by the ``venv`` module. ``venv`` module.
* This is similar to the existing ``virtualenv`` package for which many * This is similar to the existing ``virtualenv`` package for which many
downstream distributors have already made exception to the common downstream distributors have already made exception to the common
"debundling" policy. "debundling" policy.
@ -629,7 +633,7 @@ explicitly invoking ``pip`` following installation).
As a result, the PEP was simplified to the current design, where the As a result, the PEP was simplified to the current design, where the
bootstrapping *always* uses the private copy of ``pip``. Contacting PyPI bootstrapping *always* uses the private copy of ``pip``. Contacting PyPI
is now always an explicit seperate step, with direct access to the full is now always an explicit separate step, with direct access to the full
pip interface. pip interface.
@ -656,10 +660,10 @@ Including pip directly in the standard library
Similar to this PEP is the proposal of just including pip in the standard Similar to this PEP is the proposal of just including pip in the standard
library. This would ensure that Python always includes pip and fixes all of the library. This would ensure that Python always includes pip and fixes all of the
end user facing problems with not having pip present by default. This has been end user facing problems with not having pip present by default. This has been
rejected because we've learned through the inclusion and history of rejected because we've learned, through the inclusion and history of
``distutils`` in the standard library that losing the ability to update the ``distutils`` in the standard library, that losing the ability to update the
packaging tools independently can leave the tooling in a state of constant packaging tools independently can leave the tooling in a state of constant
limbo. Making it unable to ever reasonably evolve in a timeframe that actually limbo. Making it unable to ever reasonably evolve in a time frame that actually
affects users as any new features will not be available to the general affects users as any new features will not be available to the general
population for *years*. population for *years*.
@ -693,8 +697,8 @@ Defaulting to --user installation
--------------------------------- ---------------------------------
Some consideration was given to bootstrapping pip into the per-user Some consideration was given to bootstrapping pip into the per-user
site-packages directory by default. However, this behaviour would be site-packages directory by default. However, this behavior would be
surprising (as it differs from the default behaviour of pip itself) surprising (as it differs from the default behavior of pip itself)
and is also not currently considered reliable (there are some edge cases and is also not currently considered reliable (there are some edge cases
which are not handled correctly when pip is installed into the user which are not handled correctly when pip is installed into the user
site-packages directory rather than the system site-packages). site-packages directory rather than the system site-packages).