EmailMessage(policy=SMTPUTF8).as_bytes() fails to encode non-ASCII Subject in 3.12 #133442
Description
Bug report
Bug description:
# Add a code block here, if required# test_subject_encoding.py
from email.message import EmailMessage
from email.policy import SMTPUTF8
import sys
# Use one of the subject strings that caused issues
# Make sure this is the exact string causing Mojibake
subject = 'Vectorsentinel与Drone Volt合作共赢，探索无人机安防新机遇'
print(f"Python Version: {sys.version}")
print(f"Testing subject: {repr(subject)}")
msg = EmailMessage(policy=SMTPUTF8)
msg['From'] = '[email protected]'
msg['To'] = '[email protected]'
# Use standard assignment
msg['Subject'] = subject
msg.set_content('Test body content.')
print("\n--- Message As String ---")
try:
# Use as_string() which should also trigger encoding
print(msg.as_string())
except Exception as e:
print(f"Error during as_string(): {e}\n")
print("\n--- Message As Bytes (Decoded) ---")
try:
# Use as_bytes() and decode for printing
# We are primarily interested in the Subject: line format
message_bytes = msg.as_bytes()
print(message_bytes.decode('utf-8', 'replace')) # Use utf-8 decode
except Exception as e:
print(f"Error during as_bytes(): {e}\n")Python Version: 3.12.0 (main, Jan 4 2025, 13:42:56) [Clang 16.0.0 (clang-1600.0.26.6)]
Testing subject: 'Vectorsentinel与Drone Volt合作共赢，探索无人机安防新机遇'
--- Message As String ---
From: [email protected]
To: [email protected]
Subject: Vectorsentinel与Drone Volt合作共赢，探索无人机安防新机遇
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit
MIME-Version: 1.0
Test body content.
--- Message As Bytes (Decoded) ---
From: [email protected]
To: [email protected]
Subject: Vectorsentinel与Drone Volt合作共赢，探索无人机安防新机遇
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit
MIME-Version: 1.0
Test body content.
CPython versions tested on:
3.12
Operating systems tested on:
macOS