Defer PEP 558 (defined semantics for locals()) once more (#3050)

Author: ncoghlan

pep-0558.rst

@@ -3,14 +3,40 @@ Title: Defined semantics for locals()
 Author: Nick Coghlan <[email protected]>
 BDFL-Delegate: Nathaniel J. Smith
 Discussions-To: [email protected]
-Status: Draft
+Status: Deferred
 Type: Standards Track
 Content-Type: text/x-rst
 Created: 08-Sep-2017
-Python-Version: 3.12
+Python-Version: 3.13
 Post-History: 08-Sep-2017, 22-May-2019, 30-May-2019, 30-Dec-2019, 18-Jul-2021,
               26-Aug-2021
 
+PEP Deferral
+============
+
+While the original reference implementation for this PEP served a useful purpose
+in determining that it *is* feasible to solve the known problems with the
+semantics of the ``locals()`` namespace, that implementation itself is no longer
+viable as an implementation of the PEP as written.
+
+This situation came about for two main reasons:
+
+* first, several keys parts of the original implementation were invalidated when
+  the semantic improvements arising from the development of :pep:`667` resulted in
+  the PEP as written diverging from what had previously been implemented
+* second, several remaining practical aspects of the original implementation were
+  invalidated by the frame management changes that formed part of the significant
+  performance improvements published in the CPython 3.11 release, so the development
+  branch doesn't even offer a useful starting point for an updated implementation
+
+As a result, further progress on this PEP requires the development of a new reference
+implementation, either for this PEP or for :pep:`667` (the semantics of the two PEPs
+are so close together now that an implementation for either would require only a few
+relatively small changes to instead implement the other).
+
+Since the PEP author has no current plans to produce that new reference implementation
+themselves, but the semantics proposed by the PEPs seem generally acceptable to the
+Python core development team, the most appropriate state for the PEP is "Deferred".
 
 Abstract
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