A better description for "Requires-Python" metadata field #1274
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…is should better demonstrate that usage of this field is more commonly about _excluding known incompatible versions_ than it is about specifying _guaranteed compatible versions_. Remove the multiple example code-block because it is not a (multiple use) field, and the other examples seem to exist only to show further usage of PEP 440 version specifiers (which are explained better elsewhere) rather than Requires-Python itself.
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The common usage of this field is for Dropping support for older Python versions. Adding upper bounds can be problematic.
The current description is misleading, and that was discussed extensively here, but unfortunately no PR came out of it. So here's an attempt!
I won't reproduce all of Henry's excellent arguments, but I will reiterate that the wording "is guaranteed to be compatible with" causes issues - today I've witnessed an environment failing to bootstrap when updated from Python 3.11.3 to Python 3.11.4 because one (internal) dependency had declared an upper bound on 3.11.3.
This was added because 3.11.3 was the runtime the developer's code was tested in, and if you were to take the current description literally, it's quite right that their distribution is not "guaranteed to be compatible with" 3.11.4 - how could you guarantee compatibility with an unreleased Python version? For someone unfamiliar with Python packaging, it is not obvious that such an upper bound would wreak havoc on the tooling and block an upgrade until a new release is published without over-constraining the Requires-Python metadata.