PEP 685: Fix grammar & clarity issues, improve phrasing & avoid rep

CAM-Gerlach · CAM-Gerlach · commit ba7b80bca8e7 · 2022-03-13T23:44:23.000-05:00
diff --git a/pep-0685.rst b/pep-0685.rst
@@ -28,13 +28,13 @@ name "must be a valid Python identifier".
 letter, digit, or any one of ``.``, ``-``, or ``_`` after the initial character.
 Otherwise, there is no other `PyPA specification
 <https://packaging.python.org/en/latest/specifications/>`_
-which outlines how extra names should be written or normalization for comparison.
+which outlines how extra names should be written or normalized for comparison.
 Due to the amount of packaging-related code in existence,
 it is important to evaluate current practices by the community and
-standardize on one that doesn't break most code, while being
+standardize on one that doesn't break most existing code, while being
 something tool authors can agree to following.
 
-The issue of there being no standard was brought forward by an
+The issue of there being no consistent standard was brought forward by an
 `initial discussion <https://discuss.python.org/t/7614>`__
 noting that the extra ``adhoc-ssl`` was not considered equal to the name
 ``adhoc_ssl`` by pip 22.
@@ -47,21 +47,23 @@ Rationale
 
     re.sub(r"[-_.]+", "-", name).lower()
 
-This collapses any run of the substitution character down to a single
-character,
-e.g. ``---`` gets collapsed down to ``-``.
-This does **not** produce a valid Python identifier as specified by
+This collapses any run of the characters ``-``, ``_`` and ``.``
+down to a single ``-``.
+For example, ``---`` ``.`` and ``__`` all get converted to just ``-``.
+This does **not** produce a valid Python identifier, per
 the core metadata 2.2 specification for extra names.
 
-`Setuptools 60 does normalization <https://github.com/pypa/setuptools/blob/b2f7b8f92725c63b164d5776f85e67cc560def4e/pkg_resources/__init__.py#L1324-L1330>`__
+`Setuptools 60 performs normalization <https://github.com/pypa/setuptools/blob/b2f7b8f92725c63b164d5776f85e67cc560def4e/pkg_resources/__init__.py#L1324-L1330>`__
 via::
 
     re.sub(r'[^A-Za-z0-9-.]+', '_', name).lower()
 
-The use of an underscore/``_`` differs from PEP 503's use of a
-hyphen/``-``.
-Runs of ``.`` and ``-``, unlike PEP 503, do **not** get collapsed,
-e.g. ``..`` stays the same.
+The use of an underscore/``_`` differs from PEP 503's use of a hyphen/``-``,
+and it also normalizes characters outside of those allowed by :pep`508`.
+Runs of ``.`` and ``-``, unlike PEP 503, do **not** get normalized to one ``_``,
+e.g. ``..`` stays the same. To note, this is inconsistent with this function's
+docstring, which *does* specify that all non-alphanumeric characters
+(which would include ``-`` and ``.``) are normalized and collapsed.
 
 For pip 22, its
 `"extra normalisation behaviour is quite convoluted and erratic" <pip-erratic_>`__,
@@ -96,7 +98,7 @@ name is provided as appropriate for the specified core metadata version.
 If an older core metadata version is specified and the name would be
 invalid with newer core metadata versions,
 tools SHOULD warn the user.
-Tools SHOULD warn users when an invalid extra name is read and not use
+Tools SHOULD warn users when an invalid extra name is read and SHOULD not use
 the name to avoid ambiguity.
 Tools MAY raise an error instead of a warning when reading an
 invalid name, if they so desire.
@@ -105,21 +107,20 @@ invalid name, if they so desire.
 Backwards Compatibility
 =======================
 
-Moving to :pep:`503` normalization and :pep:`508` name acceptance, it
+Moving to :pep:`503` normalization and :pep:`508` name acceptance,
 allows for all preexisting, valid names to continue to be valid.
 
 Based on `research looking at a collection of wheels on PyPI <pypi-results_>`__,
-the risk of extra name clashes is limited to 73 clashes when considering
-even invalid names,
+the risk of extra name clashes is limited to 73 instances when considering
+all extras names on PyPI, valid or not (not just those within a single package)
 while *only* looking at valid names leads to only 3 clashes:
 
 * ``dev-test``: ``dev_test``, ``dev-test``, ``dev.test``
 * ``dev-lint``: ``dev-lint``, ``dev.lint``, ``dev_lint``
 * ``apache-beam``: ``apache-beam``, ``apache.beam``
 
 By requiring tools writing core metadata to only record the normalized name,
-the issue of preexisting, invalid extra names should be diminished over
-time.
+the issue of preexisting, invalid extra names should diminish over time.
 
 .. _pypi-results: https://discuss.python.org/t/14141/17
 
@@ -128,7 +129,7 @@ Security Implications
 =====================
 
 It is possible that for a distribution that has conflicting extra names, a
-tool ends up installing distributions that somehow weaken the security
+tool ends up installing dependencies that somehow weaken the security
 of the system.
 This is only hypothetical and if it were to occur,
 it would probably be more of a security concern for the distributions
@@ -149,7 +150,7 @@ Reference Implementation
 
 No reference implementation is provided aside from the code above,
 but the expectation is the `packaging project`_ will provide a
-function in its ``packaging.utils`` that will implement extra name
+function in its ``packaging.utils`` module that will implement extra name
 normalization.
 It will also implement extra name comparisons appropriately.
 Finally, if the project ever gains the ability to write out metadata,
@@ -162,17 +163,12 @@ Rejected Ideas
 Using setuptools 60's normalization
 -----------------------------------
 
-Initially, this PEP proposed following setuptools to try to minimize
-backwards-compatibility issues.
-But after checking various wheels on PyPI,
+Initially, this PEP proposed using setuptools ``safe_extra()`` for normalization
+to try to minimize backwards-compatibility issues.
+However, after checking various wheels on PyPI,
 it became clear that standardizing **all** naming on :pep:`508` and
-:pep:`503` semantics was easier and better long-term.
-
-
-Open Issues
-===========
-
-N/A
+:pep:`503` semantics was easier and better long-term,
+while causing minimal backwards compatibility issues.
 
 
 Copyright
