Meta: Clearly document current guidance for changing existing PEPs (python#2378)

* Meta: Document expectations for changing existing PEPs in contrib guide

* Meta: Clarify commit message/PR title prefixes in contrib guide

* Meta: Further improve change policy in CG per Jelle's feedback

* Meta: Reduce verbosity and perscriptiveness of changes section in CG

* Meta: Move more general/normative PEP modification guidance to PEP 1

* Meta: Further revise PEP change guidance to reflect current reality

* Meta: Update, simplify and consolidate guidance on changing PEPs

* PEP 1: Remove sentence explicitly discussing changing governance PEPs

Author: CAM-Gerlach

CONTRIBUTING.rst

@@ -18,12 +18,39 @@ first in an appropriate venue, drafting a PEP and gathering feedback, and
 developing at least a prototype reference implementation of your idea.
 
 
+Contributing changes to existing PEPs
+-------------------------------------
+
+In general, most non-Draft/Active PEPs are considered to be historical
+documents rather than living specifications or documentation. Major changes to
+their core content usually require a new PEP, while smaller modifications may
+or may not be appropriate, depending on the PEP's status. See `PEP Maintenance
+<https://peps.python.org/pep-0001/#pep-maintenance>`_
+and `Changing Existing PEPs
+<https://peps.python.org/pep-0001/#changing-existing-peps>`_ in PEP 1 for more.
+
+Copyediting and proofreading Draft and Active PEPs is welcome (subject to
+review by the PEP author), and can be done via pull request to this repo.
+Substantive content changes should first be proposed on PEP discussion threads.
+We do advise against PRs that simply mass-correct minor typos on older PEPs
+which don't significantly impair meaning and understanding.
+
+If you're still unsure, we encourage you to reach out first before opening a
+PR here. For example, you could contact the PEP author(s), propose your idea in
+a discussion venue appropriate to the PEP (such as `Typing-SIG
+<https://mail.python.org/archives/list/[email protected]/>`__ for static
+typing, or `Packaging Discourse <https://discuss.python.org/c/packaging/>`__
+for packaging), or `open an issue <https://github.com/python/peps/issues>`__.
+
+
 Commit messages and PR titles
 -----------------------------
 
-When adding or modifying a PEP, please always include the PEP number in the
-commit summary and pull request title.
-For example, ``PEP NNN: <summary of changes>``.
+When adding or modifying a PEP, please include the PEP number in the commit
+summary and pull request title. For example, ``PEP NNN: <summary of changes>``.
+Likewise, prefix rendering infrastructure changes with ``Infra:``, linting
+alterations with ``Lint:`` and other non-PEP meta changes, such as updates to
+the Readme/Contributing Guide, issue/PR template, etc., with ``Meta:``.
 
 
 Sign the CLA
@@ -122,11 +149,3 @@ or against all files with
 .. code-block:: bash
 
     pre-commit run --all-files --hook-stage manual codespell
-
-**Note**: While fixing spelling mistakes as part of more substantive
-copyediting and proofreading of draft and active PEPs is okay,
-we generally advise against PRs that simply mass-correct minor typos on
-older PEPs that don't significantly impair meaning and understanding,
-as these tend to create a fairly high level of noise and churn for
-PEP readers, authors and editors relative to the amount of practical value
-they provide.

pep-0001.txt

@@ -460,19 +460,25 @@ if they are never meant to be completed.  E.g. :pep:`1` (this PEP).
 PEP Maintenance
 ---------------
 
-In general, Standards track PEPs are no longer modified after they have
-reached the Final state. Once a PEP has been completed, the Language and
-Standard Library References become the formal documentation of the expected
-behavior.
+In general, PEPs are no longer substantially modified after they have reached
+the Accepted, Final, Rejected or Superseded state. Once resolution is reached,
+a PEP is considered a historical document rather than a living specification.
+Formal documentation of the expected behavior should be maintained elsewhere,
+such as the `Language Reference`_ for core features, the `Library Reference`_
+for standard library modules or the `PyPA Specifications`_ for packaging.
 
 If changes based on implementation experience and user feedback are made to
-Standards track PEPs while in the Accepted or Provisional State, those changes
-should be noted in the PEP, such that the PEP accurately describes the state of
+Standards track PEPs while in the Provisional or (with SC approval) Accepted
+state, they should be noted in the PEP, such that the PEP accurately describes
 the implementation at the point where it is marked Final.
 
-Informational and Process PEPs may be updated over time to reflect changes
-to development practices and other details. The precise process followed in
-these cases will depend on the nature and purpose of the PEP being updated.
+Active (Informational and Process) PEPs may be updated over time to reflect
+changes to development practices and other details. The precise process
+followed in these cases will depend on the nature and purpose of the PEP
+in question.
+
+Occasionally, a Deferred or even a Withdrawn PEP may be resurrected
+with major updates, but it is often better to just propose a new one.
 
 
 What belongs in a successful PEP?
@@ -699,23 +705,21 @@ Alternatively, all support files may be placed in a subdirectory called
 are no constraints on the names used in files.
 
 
-Reporting PEP Bugs, or Submitting PEP Updates
-=============================================
-
-How you report a bug, or submit a PEP update depends on several
-factors, such as the maturity of the PEP, the preferences of the PEP
-author, and the nature of your comments.  For the early draft stages
-of the PEP, it's probably best to send your comments and changes
-directly to the PEP author.  For more mature, or finished PEPs you may
-want to submit corrections as a `GitHub issue`_ or `GitHub pull request`_ so that
-your changes don't get lost.
+Changing Existing PEPs
+======================
 
-When in doubt about where to send your changes, please check first
-with the PEP author and/or a PEP editor.
+Draft PEPs are freely open for discussion and proposed modification, at the
+discretion of the authors, until submitted to the Steering Council or
+PEP-Delegate for review and resolution. Substantive content changes should
+generally be first proposed on the PEP's discussion thread listed in its
+``Discussions-To`` header, while copyedits and corrections can be submitted
+as a `GitHub issue`_ or `GitHub pull request`_.
+PEP authors with write access to the PEP repository can update the PEPs
+themselves by using ``git push`` or a GitHub PR to submit their changes.
+For guidance on modifying other PEPs, consult the `PEP Maintenance`_ section.
 
-PEP authors with write access to the PEP repository can update the
-PEPs themselves by using "git push" or the GitHub PR interface to submit their
-changes.
+See the `Contributing Guide`_ for additional details, and when in doubt,
+please check first with the PEP author and/or a PEP editor.
 
 
 Transferring PEP Ownership
@@ -858,6 +862,14 @@ Footnotes
 
 .. _Packaging category: https://discuss.python.org/c/packaging/
 
+.. _Language Reference: https://docs.python.org/3/reference/index.html
+
+.. _Library Reference: https://docs.python.org/3/library/index.html
+
+.. _PyPA Specifications: https://packaging.python.org/en/latest/specifications/
+
+.. _Contributing Guide: https://github.com/python/peps/blob/main/CONTRIBUTING.rst
+
 
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