Handle empty lists in strict email.utils.parseaddr #159350

The strict path in email.utils.parseaddr() handles list input by reading its first item without checking for an empty list. The non-strict path returns an empty address pair for the same input.

Reproducer, run with the interpreter built from the CPython checkout:

from email.utils import parseaddr

print(parseaddr([], strict=False))
print(parseaddr([]))

Expected: Both calls return ('', '').

Observed: The default strict call raises IndexError.

Environment: CPython main, Windows debug build.

Linked PRs

• gh-159350: Handle empty lists in strict email.utils.parseaddr #159351