Update for GH-104802: register a defect instead of raising an error

Based on PR review

Author: fsc-eriker

Lib/email/_header_value_parser.py

@@ -1514,18 +1514,19 @@ def get_obs_local_part(value):
             token, value = get_cfws(value)
         obs_local_part.append(token)
     if not obs_local_part:
-        raise(errors.HeaderParseError(
-            "abandoning parse; truncated value? ({})".format(value)))
-    if (obs_local_part[0].token_type == 'dot' or
+        obs_local_part.defects.append(errors.InvalidHeaderDefect(
+            "abandoned parse; truncated value?"))
+    else:
+        if (obs_local_part[0].token_type == 'dot' or
             obs_local_part[0].token_type=='cfws' and
             obs_local_part[1].token_type=='dot'):
-        obs_local_part.defects.append(errors.InvalidHeaderDefect(
-            "Invalid leading '.' in local part"))
-    if (obs_local_part[-1].token_type == 'dot' or
+            obs_local_part.defects.append(errors.InvalidHeaderDefect(
+                "Invalid leading '.' in local part"))
+        if (obs_local_part[-1].token_type == 'dot' or
             obs_local_part[-1].token_type=='cfws' and
             obs_local_part[-2].token_type=='dot'):
-        obs_local_part.defects.append(errors.InvalidHeaderDefect(
-            "Invalid trailing '.' in local part"))
+            obs_local_part.defects.append(errors.InvalidHeaderDefect(
+                "Invalid trailing '.' in local part"))
     if obs_local_part.defects:
         obs_local_part.token_type = 'invalid-obs-local-part'
     return obs_local_part, value

Lib/test/test_email/test__header_value_parser.py

@@ -2588,10 +2588,21 @@ def test_get_msg_id_empty(self):
         with self.assertRaises(errors.HeaderParseError):
             parser.get_msg_id('')
 
-    def test_get_msg_id_botched(self):
-        # gh-105802: ditto for broken Microsoft Message-Id
-        with self.assertRaises(errors.HeaderParseError):
-            parser.get_msg_id('<[83c48dddbea7492e873224a5ae1c04be-JFBVALKQOJXWILKNK4YVA7CBPJ2XEZKEMV3E64DTPRCW2YLJNR6EK6DPKNWXI4A=@microsoft.com]>')
+    def test_get_msg_id_square_brackets(self):
+        # gh-105802: test for broken Microsoft Message-Id with square brackets.
+        msg_id = self._test_get_x(
+            parser.get_msg_id,
+            '<[[email protected]]>',
+            '<', # sic
+            '<', # sic
+            # This also triggers
+            # ObsoleteHeaderDefect('obsolete id-left in msg-id')
+            # and InvalidHeaderDefect('msg-id with no id-right')
+            [errors.ObsoleteHeaderDefect, errors.InvalidHeaderDefect,
+             errors.InvalidHeaderDefect],
+            '[[email protected]]>',
+            )
+        self.assertEqual(msg_id.token_type,'msg-id')
 
     def test_get_msg_id_valid(self):
         msg_id = self._test_get_x(