Return None for MX when deliverability is unknown

CHANGELOG.md

@@ -1,6 +1,7 @@
 In Development
 --------------
 
+* The `mx` field is now `None` when a deliverability check cannot be completed, as documented, instead of being absent from the returned object.
 * Python 3.8 and 3.9 are no longer supported.
 * The `original` field of the returned validated email object incorrectly un-escaped the local part of the email address. Now it returns the original address, without any display name, as passed to validate_email.
 * add support python3.15

email_validator/types.py

@@ -40,8 +40,9 @@ class ValidatedEmail:
     smtputf8: bool
 
     """If a deliverability check is performed and if it succeeds, a list of (priority, domain)
-    tuples of MX records specified in the DNS for the domain."""
-    mx: list[tuple[int, str]]
+    tuples of MX records specified in the DNS for the domain. None if the check
+    could not be completed because of a temporary issue."""
+    mx: Optional[list[tuple[int, str]]]
 
     """If no MX records are actually specified in DNS and instead are inferred, through an obsolete
     mechanism, from A or AAAA records, the value is the type of DNS record used instead (`A` or `AAAA`)."""
@@ -92,6 +93,8 @@ def __getitem__(self, key: str) -> Optional[str] | bool | list[tuple[int, str]]:
     def __eq__(self, other: object) -> bool:
         if not isinstance(other, ValidatedEmail):
             return False
+        self_mx = getattr(self, 'mx', None)
+        other_mx = getattr(other, 'mx', None)
         return (
             getattr(self, 'original', None) == getattr(other, 'original', None)
             and self.normalized == other.normalized
@@ -101,8 +104,8 @@ def __eq__(self, other: object) -> bool:
             and getattr(self, 'ascii_local_part', None) == getattr(other, 'ascii_local_part', None)
             and getattr(self, 'ascii_domain', None) == getattr(other, 'ascii_domain', None)
             and self.smtputf8 == other.smtputf8
-            and repr(sorted(self.mx) if getattr(self, 'mx', None) else None)
-            == repr(sorted(other.mx) if getattr(other, 'mx', None) else None)
+            and repr(sorted(self_mx) if self_mx else None)
+            == repr(sorted(other_mx) if other_mx else None)
             and getattr(self, 'mx_fallback_type', None) == getattr(other, 'mx_fallback_type', None)
             and getattr(self, 'display_name', None) == getattr(other, 'display_name', None)
         )

email_validator/validate_email.py

@@ -199,9 +199,7 @@ def validate_email(
         deliverability_info = validate_email_deliverability(
             ret.ascii_domain, ret.domain, timeout, dns_resolver
         )
-        mx = deliverability_info.get("mx")
-        if mx is not None:
-            ret.mx = mx
+        ret.mx = deliverability_info.get("mx")
         ret.mx_fallback_type = deliverability_info.get("mx_fallback_type")
 
     return ret

tests/test_deliverability.py

@@ -1,5 +1,6 @@
 from typing import Any
 
+import dns.resolver
 import pytest
 import re
 
@@ -66,6 +67,16 @@ def test_deliverability_dns_timeout() -> None:
     assert response.get("unknown-deliverability") == "timeout"
 
 
+@pytest.mark.parametrize('dns_resolver', [RESOLVER, dns.resolver.Resolver(configure=False)])
+def test_validated_email_mx_unknown(dns_resolver: dns.resolver.Resolver) -> None:
+    # The saved resolver simulates a timeout; the empty resolver has no nameservers.
+    result = validate_email('me@timeout.com', dns_resolver=dns_resolver)
+    assert result.normalized == 'me@timeout.com'
+    assert result.mx is None
+    assert result.mx_fallback_type is None
+    assert result.as_dict()['mx'] is None
+
+
 def test_timeout_and_resolver() -> None:
     with pytest.raises(ValueError, match="It's not valid to pass both timeout and dns_resolver."):
         validate_email_deliverability('timeout.com', 'timeout.com', timeout=1, dns_resolver=RESOLVER)