[Dhairya-007]

_validate_python_version loops over the comma-separated versions in a
Python-Version header, but the "no micro part" branch used return instead of
continue:

for version in versions:
    ...
    if micro == "":
        return          # ends the generator, not just this iteration
    if minor == "x":
        yield ...

The function is a generator, so return ends the whole validation rather than
moving on to the next version. Two-segment versions (3.12, 3.0) are the
overwhelming majority, so in practice only the first entry of a
Python-Version header was ever checked:

>>> _validate_python_version(1, "3.0, 3.a")       # minor part is not numeric
[]
>>> _validate_python_version(1, "3.12, 4.0")      # major part is not 1, 2 or 3
[]
>>> _validate_python_version(1, "3.11, 3.x.1")    # micro part with an 'x' minor
[]
>>> _validate_python_version(1, "3.9, 3.09")      # leading zero in the minor
[]

All four are reported after the change. None of the checks were missing — they
were simply unreachable for every version after the first.

return → continue is the whole fix.

Checks

• python3 check-peps.py over all PEPs still exits 0, so no currently committed
  PEP trips the newly reachable checks — this does not turn CI red.
• The existing test_validate_python_version builds its expected messages from
  the whole line, so it can only describe single-version headers. I added
  test_validate_python_version_all_versions for lists; five of its seven cases
  fail without the fix.
• pytest pep_sphinx_extensions/tests/pep_lint/ → 469 passed, and black and
  ruff are clean on both files.

One deliberate non-change

An AST sweep for return inside a loop in a generator turns up one other hit,
_validate_discussions_to. There the return is correct — it suppresses the
catch-all "must be a valid thread URL, mailing list, or 'Pending'" error once a
known suffix matches — so I left it alone.

[read-the-docs-community]

Documentation build overview

📚 pep-previews | 🛠️ Build #35738717 | 📁 Comparing 60ebe78 against latest (dfc3d95)

  🔍 Preview build  

7 files changed · ± 7 modified

± Modified

• pep-0001/index.html
• pep-0653/index.html
• pep-0720/index.html
• pep-0776/index.html
• pep-0786/index.html
• pep-0818/index.html
• pep-0824/index.html

[Dhairya-007]

@StanFromIreland would you mind taking a look? This one is a check-peps.py logic fix rather than prose: return inside the version loop meant only the first entry of a Python-Version header was ever validated.

[StanFromIreland]

Duplicate of #5221.