Fix TypeError from unconditional strict= kwarg on old Python patch releases#162
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Fix TypeError from unconditional strict= kwarg on old Python patch releases#162mkilijanek wants to merge 1 commit into
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…support it email.utils.getaddresses() only gained the strict= keyword as part of the CVE-2023-27043 hardening, and it was backported to patch releases >=3.10.15, >=3.11.10, >=3.12.6 rather than to every release across those minor versions. get_addresses() passed strict=True unconditionally, so on an older patch release within an otherwise supported minor version this raised: TypeError: getaddresses() got an unexpected keyword argument 'strict' for every address header, breaking mail-parser entirely on those interpreters. email.utils.supports_strict_parsing is the stdlib's own capability flag for this hardening; get_addresses() now checks it and only passes strict= when the running interpreter actually supports it, falling back to the pre-hardening call signature otherwise. The existing regex fallback for RFC-non-compliant display names, and every other code path, is unaffected on interpreters that do support strict parsing (the common case in CI and production). Reported via a downstream consumer, parsedmarc: domainaware/parsedmarc#808
This was referenced Jul 13, 2026
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mailparser.parse_from_string() unconditionally passes strict=True to email.utils.getaddresses(), which only exists on Python patch releases >=3.10.15, >=3.11.10, >=3.12.6 (the CVE-2023-27043 backports). On an older patch release within an otherwise-supported minor version, this raises TypeError: getaddresses() got an unexpected keyword argument 'strict' -- and parsedmarc's existing broad exception handlers silently turned that into a generic "invalid report" error, with nothing indicating the real cause was an outdated Python patch release rather than a bad report. _mailparser_parse_from_string() now catches this specific TypeError, gated on email.utils.supports_strict_parsing so unrelated TypeErrors still pass through untouched, and re-raises as EmailParserError naming the required Python versions. The existing catch-alls in parse_report_email() and parse_failure_report() already embed the inner exception's message into their own, so the clearer text reaches operators with no other control-flow changes. The real fix belongs upstream in mail-parser: filed as SpamScope/mail-parser#162 (open, not yet merged as of this commit). This is a workaround for parsedmarc users in the meantime. Fixes domainaware#808. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
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Someone beat you to it. #161 |
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Summary
get_addresses()unconditionally passesstrict=Truetoemail.utils.getaddresses(). That keyword only exists as part of the CVE-2023-27043 hardening, and CPython backported it to patch releases>=3.10.15,>=3.11.10,>=3.12.6— not to every release within those minor versions. On an older patch release (e.g. 3.11.3), callingget_addresses()for any address header raises:which breaks address parsing entirely on that interpreter (and, transitively, any project depending on mail-parser to parse address headers on such a host).
Reported via a downstream consumer (parsedmarc): domainaware/parsedmarc#808
Fix
email.utils.supports_strict_parsingis the stdlib's own capability flag for this hardening (present andTrueon the patched releases above).get_addresses()now checks it and only passesstrict=Truewhen the running interpreter actually supports it, falling back to the pre-hardening call signature (getaddresses([raw_header])) otherwise. Everything else — the existing regex fallback for RFC-non-compliant display names,Headerhandling, etc. — is unaffected on interpreters that do support strict parsing, which is the common case in CI and production.Test plan
test_get_addresses_omits_strict_kwarg_when_unsupportedandtest_get_addresses_uses_strict_kwarg_when_supportedtotests/test_utils.py, both mockingemail.utils.getaddresses/email.utils.supports_strict_parsingto assert the exact call signature used in each case.uv run pytest tests/— 212 passed (full suite, including theoutlookextra).uv run ruff check ./uv run ruff format --check .— clean.pre-commit run --all-fileson the touched files — all hooks pass, including thepyrighthook.