Several messages in one connection: Adding manipulations after End of Message callback is not allowed

[atatarn]

Here I'm sending several messages in one single connection to Postfix.
Despite warning saying that AppendHeader was ignored for 2 and 3 message, all 3 of them had the header set.
But at the same time, if using dynamic/different-per-message header value - "new" values will be indeed ignored and all messages will receive only the first value of the header.

Could anything be done to fix that behaviour?

INFO:purepythonmilter.server.milterserver:Purepythonmilter version 0.0.1 starting...
INFO:purepythonmilter.server.milterserver:Server started, awaiting connections on 0.0.0.0:9000...

INFO:debug_log_all:566f5380: On connect: args=ConnectionInfoArgsIPv4(hostname='[172.21.0.1]', addr=IPv4Address('172.21.0.1'), port=45616), macros={'j': 'relay.localhost', '{daemon_name}': 'relay.localhost', '{daemon_addr}': '172.21.0.2', 'v': 'Postfix 3.7.11', '_': 'unknown [172.21.0.1]'}
INFO:debug_log_all:566f5380: On MAIL FROM: address=no-reply@first.local, esmtp_args={'size': '585'}, macros={'{auth_type}': 'CRAM-MD5', '{auth_authen}': 'first@relay', '{mail_addr}': 'no-reply@first.local', '{mail_host}': 'first.local', '{mail_mailer}': 'smtp'}
INFO:debug_log_all:566f5380: On RCPT TO: address=sandra34@example.org, esmtp_args={}, macros={'{rcpt_addr}': 'sandra34@example.org', '{rcpt_host}': 'example.org', '{rcpt_mailer}': 'smtp'}
INFO:debug_log_all:566f5380: On end of message: macros={'i': 'BFC21E0FD9'}

INFO:debug_log_all:566f5380: On MAIL FROM: address=no-reply@first.local, esmtp_args={'size': '594'}, macros={'{auth_type}': 'CRAM-MD5', '{auth_authen}': 'first@relay', '{mail_addr}': 'no-reply@first.local', '{mail_host}': 'first.local', '{mail_mailer}': 'smtp'}
INFO:debug_log_all:566f5380: On RCPT TO: address=michellefriedman@example.com, esmtp_args={}, macros={'{rcpt_addr}': 'michellefriedman@example.com', '{rcpt_host}': 'example.com', '{rcpt_mailer}': 'smtp'}
INFO:debug_log_all:566f5380: On end of message: macros={'i': 'CEE43E0FE1'}

WARNING:purepythonmilter.server.session:566f5380: Adding manipulations after End of Message callback is not allowed; ignoring: [AppendHeader(headername='X-Fooo', headertext='BAR')].

INFO:debug_log_all:566f5380: On MAIL FROM: address=no-reply@first.local, esmtp_args={'size': '601'}, macros={'{auth_type}': 'CRAM-MD5', '{auth_authen}': 'first@relay', '{mail_addr}': 'no-reply@first.local', '{mail_host}': 'first.local', '{mail_mailer}': 'smtp'}
INFO:debug_log_all:566f5380: On RCPT TO: address=victoriaday@example.org, esmtp_args={}, macros={'{rcpt_addr}': 'victoriaday@example.org', '{rcpt_host}': 'example.org', '{rcpt_mailer}': 'smtp'}
INFO:debug_log_all:566f5380: On end of message: macros={'i': 'DC15FE1084'}

WARNING:purepythonmilter.server.session:566f5380: Adding manipulations after End of Message callback is not allowed; ignoring: [AppendHeader(headername='X-Fooo', headertext='BAR')].

[duobradovic]

Duplicate of #16