9 files changed, 5 insertions, 107 deletions

diff --git a/src/mailman/app/docs/chains.txt b/src/mailman/app/docs/chains.txt
index 927004e27..216bf2f5b 100644
--- a/src/mailman/app/docs/chains.txt
+++ b/src/mailman/app/docs/chains.txt
@@ -159,7 +159,6 @@ This message is addressed to the mailing list moderators.
     MIME-Version: 1.0
     Content-Transfer-Encoding: 7bit
     Subject: confirm ...
-    Sender: _xtest-request@example.com
     From: _xtest-request@example.com
     ...
     <BLANKLINE>
diff --git a/src/mailman/archiving/docs/common.txt b/src/mailman/archiving/docs/common.txt
index 62b407486..18400da42 100644
--- a/src/mailman/archiving/docs/common.txt
+++ b/src/mailman/archiving/docs/common.txt
@@ -103,8 +103,6 @@ address at the Mail-Archive.  The message gets no header or footer decoration.
     Subject: An archived message
     Message-ID: <12345>
     X-Message-ID-Hash: ZaXPPxRMM9_hFZL4vTRlQlBx8pc=
-    Sender: test-bounces@example.com
-    Errors-To: test-bounces@example.com
     X-Peer: 127.0.0.1:...
     X-MailFrom: test-bounces@example.com
     X-RcptTo: archive@mail-archive.dev
diff --git a/src/mailman/chains/hold.py b/src/mailman/chains/hold.py
index 6755fe904..f5ff237d9 100644
--- a/src/mailman/chains/hold.py
+++ b/src/mailman/chains/hold.py
@@ -233,7 +233,6 @@ message will be approved for posting to the list.  The Approved: header can
 also appear in the first line of the body of the reply.""")),
                                 _charset=language.charset)
                 dmsg['Subject'] = 'confirm ' + token
-                dmsg['Sender'] = mlist.request_address
                 dmsg['From'] = mlist.request_address
                 dmsg['Date'] = formatdate(localtime=True)
                 dmsg['Message-ID'] = make_msgid()
diff --git a/src/mailman/mta/base.py b/src/mailman/mta/base.py
index 7b254fd3e..2f1470d56 100644
--- a/src/mailman/mta/base.py
+++ b/src/mailman/mta/base.py
@@ -67,18 +67,8 @@ class BaseDelivery:
         :return: delivery failures as defined by `smtplib.SMTP.sendmail`
         :rtype: dictionary
         """
-        # Blow away any existing Sender and Errors-To headers and substitute
-        # our own.  Our interpretation of RFC 5322 $3.6.2 is that Mailman is
-        # the "agent responsible for actual transmission of the message"
-        # because what we send to list members is different than what the
-        # original author sent.  RFC 2076 says Errors-To is "non-standard,
-        # discouraged" but we include it for historical purposes.
-        sender = self._get_sender(mlist, msg, msgdata)
-        del msg['sender']
-        del msg['errors-to']
-        msg['Sender'] = sender
-        msg['Errors-To'] = sender
         # Do the actual sending.
+        sender = self._get_sender(mlist, msg, msgdata)
         message_id = msg['message-id']
         try:
             refused = self._connection.sendmail(
diff --git a/src/mailman/mta/docs/bulk.txt b/src/mailman/mta/docs/bulk.txt
index 925d29554..a15a30279 100644
--- a/src/mailman/mta/docs/bulk.txt
+++ b/src/mailman/mta/docs/bulk.txt
@@ -215,22 +215,8 @@ each with 20 addresses in the RCPT TO header.
 Delivery headers
 ================
 
-The message delivered to bulk recipients has its Sender and Errors-To headers
-set to some Mailman-responsible agent that can handle such errors, for example
-the -bounces robot for the list or the site owner's address.  The relevant
-RFCs are 5321, 5322, and 2076.
-
-It is arguably incorrect for Mailman to touch the Sender header, if the
-interpretation is such that the original author's agent is considered the
-"agent responsible for actual transmission of the message" (RFC 5322 $3.6.2).
-On the other hand, a reasonable argument can be made that Mailman is the
-responsible agent since the message being received by list members is
-different than the message sent by the original author.  We make the latter
-interpretation, and thus Mailman removes all existing Sender headers and
-inserts its own.
-
-RFC 2076 states that Errors-To is "non-standard, discouraged".  We treat it
-the same as Sender for historical de-facto purposes.
+The sending agent shows up in the RFC 5321 MAIL FROM header, which shows up in
+the X-MailFrom header in the sample message.
 
 The bulk delivery module calculates the sending agent address first from the
 message metadata...
@@ -248,8 +234,6 @@ message metadata...
     To: test@example.com
     Subject: test one
     Message-ID: <aardvark>
-    Sender: asender@example.org
-    Errors-To: asender@example.org
     X-Peer: ...
     X-MailFrom: asender@example.org
     X-RcptTo: aperson@example.com
@@ -268,8 +252,6 @@ message metadata...
     To: test@example.com
     Subject: test one
     Message-ID: <aardvark>
-    Sender: test-bounces@example.com
-    Errors-To: test-bounces@example.com
     X-Peer: ...
     X-MailFrom: test-bounces@example.com
     X-RcptTo: aperson@example.com
@@ -293,45 +275,13 @@ message.
     To: test@example.com
     Subject: test one
     Message-ID: <aardvark>
-    Sender: site-owner@example.com
-    Errors-To: site-owner@example.com
     X-Peer: ...
     X-MailFrom: site-owner@example.com
     X-RcptTo: aperson@example.com
     <BLANKLINE>
     This is a test.
 
-Any existing Sender or Errors-To headers in the original message are always
-deleted first.
-
-    >>> msg = message_from_string("""\
-    ... From: bperson@example.org
-    ... To: test@example.com
-    ... Subject: test two
-    ... Message-ID: <badger>
-    ... Sender: robot@example.org
-    ... Errors-To: robot@example.org
-    ...
-    ... This is a test.
-    ... """)
-
-    >>> bulk.deliver(mlist, msg, msgdata)
-    {}
-
-    >>> message = list(smtpd.messages)[0]
-    >>> print message.as_string()
-    From: bperson@example.org
-    To: test@example.com
-    Subject: test two
-    Message-ID: <badger>
-    Sender: test-bounces@example.com
-    Errors-To: test-bounces@example.com
-    X-Peer: ...
-    X-MailFrom: test-bounces@example.com
-    X-RcptTo: aperson@example.com
-    <BLANKLINE>
-    This is a test.
-
+    # Remove test configuration.
     >>> config.pop('site-owner')
 
 
diff --git a/src/mailman/mta/docs/decorating.txt b/src/mailman/mta/docs/decorating.txt
index 935d9e349..f89d0b102 100644
--- a/src/mailman/mta/docs/decorating.txt
+++ b/src/mailman/mta/docs/decorating.txt
@@ -99,8 +99,6 @@ The decorations happen when the message is delivered.
     MIME-Version: 1.0
     Content-Type: text/plain; charset="us-ascii"
     Content-Transfer-Encoding: 7bit
-    Sender: test-bounces@example.com
-    Errors-To: test-bounces@example.com
     X-Peer: ...
     X-MailFrom: test-bounces@example.com
     X-RcptTo: aperson@example.com
@@ -120,8 +118,6 @@ The decorations happen when the message is delivered.
     MIME-Version: 1.0
     Content-Type: text/plain; charset="us-ascii"
     Content-Transfer-Encoding: 7bit
-    Sender: test-bounces@example.com
-    Errors-To: test-bounces@example.com
     X-Peer: ...
     X-MailFrom: test-bounces@example.com
     X-RcptTo: bperson@example.com
@@ -141,8 +137,6 @@ The decorations happen when the message is delivered.
     MIME-Version: 1.0
     Content-Type: text/plain; charset="us-ascii"
     Content-Transfer-Encoding: 7bit
-    Sender: test-bounces@example.com
-    Errors-To: test-bounces@example.com
     X-Peer: ...
     X-MailFrom: test-bounces@example.com
     X-RcptTo: cperson@example.com
@@ -177,8 +171,6 @@ into the message metadata.
     To: test@example.com
     Subject: test one
     Message-ID: <aardvark>
-    Sender: test-bounces@example.com
-    Errors-To: test-bounces@example.com
     X-Peer: ...
     X-MailFrom: test-bounces@example.com
     X-RcptTo: aperson@example.com
@@ -189,8 +181,6 @@ into the message metadata.
     To: test@example.com
     Subject: test one
     Message-ID: <aardvark>
-    Sender: test-bounces@example.com
-    Errors-To: test-bounces@example.com
     X-Peer: ...
     X-MailFrom: test-bounces@example.com
     X-RcptTo: bperson@example.com
@@ -201,8 +191,6 @@ into the message metadata.
     To: test@example.com
     Subject: test one
     Message-ID: <aardvark>
-    Sender: test-bounces@example.com
-    Errors-To: test-bounces@example.com
     X-Peer: ...
     X-MailFrom: test-bounces@example.com
     X-RcptTo: cperson@example.com
diff --git a/src/mailman/mta/docs/personalized.txt b/src/mailman/mta/docs/personalized.txt
index 7e4331b97..38494b725 100644
--- a/src/mailman/mta/docs/personalized.txt
+++ b/src/mailman/mta/docs/personalized.txt
@@ -57,8 +57,6 @@ By default, the To header is not personalized.
     To: test@example.com
     Subject: test one
     Message-ID: <aardvark>
-    Sender: test-bounces@example.com
-    Errors-To: test-bounces@example.com
     X-Peer: ...
     X-MailFrom: test-bounces@example.com
     X-RcptTo: aperson@example.com
@@ -69,8 +67,6 @@ By default, the To header is not personalized.
     To: test@example.com
     Subject: test one
     Message-ID: <aardvark>
-    Sender: test-bounces@example.com
-    Errors-To: test-bounces@example.com
     X-Peer: ...
     X-MailFrom: test-bounces@example.com
     X-RcptTo: bperson@example.com
@@ -81,8 +77,6 @@ By default, the To header is not personalized.
     To: test@example.com
     Subject: test one
     Message-ID: <aardvark>
-    Sender: test-bounces@example.com
-    Errors-To: test-bounces@example.com
     X-Peer: ...
     X-MailFrom: test-bounces@example.com
     X-RcptTo: cperson@example.com
@@ -114,8 +108,6 @@ the recipient's address and name.
     To: aperson@example.com
     Subject: test one
     Message-ID: <aardvark>
-    Sender: test-bounces@example.com
-    Errors-To: test-bounces@example.com
     X-Peer: ...
     X-MailFrom: test-bounces@example.com
     X-RcptTo: aperson@example.com
@@ -126,8 +118,6 @@ the recipient's address and name.
     To: bperson@example.com
     Subject: test one
     Message-ID: <aardvark>
-    Sender: test-bounces@example.com
-    Errors-To: test-bounces@example.com
     X-Peer: ...
     X-MailFrom: test-bounces@example.com
     X-RcptTo: bperson@example.com
@@ -138,8 +128,6 @@ the recipient's address and name.
     To: cperson@example.com
     Subject: test one
     Message-ID: <aardvark>
-    Sender: test-bounces@example.com
-    Errors-To: test-bounces@example.com
     X-Peer: ...
     X-MailFrom: test-bounces@example.com
     X-RcptTo: cperson@example.com
@@ -172,8 +160,6 @@ associated real name, then this name also shows up in the To header.
     To: aperson@example.com
     Subject: test one
     Message-ID: <aardvark>
-    Sender: test-bounces@example.com
-    Errors-To: test-bounces@example.com
     X-Peer: ...
     X-MailFrom: test-bounces@example.com
     X-RcptTo: aperson@example.com
@@ -184,8 +170,6 @@ associated real name, then this name also shows up in the To header.
     To: Bill Person <bperson@example.com>
     Subject: test one
     Message-ID: <aardvark>
-    Sender: test-bounces@example.com
-    Errors-To: test-bounces@example.com
     X-Peer: ...
     X-MailFrom: test-bounces@example.com
     X-RcptTo: bperson@example.com
@@ -196,8 +180,6 @@ associated real name, then this name also shows up in the To header.
     To: Cate Person <cperson@example.com>
     Subject: test one
     Message-ID: <aardvark>
-    Sender: test-bounces@example.com
-    Errors-To: test-bounces@example.com
     X-Peer: ...
     X-MailFrom: test-bounces@example.com
     X-RcptTo: cperson@example.com
diff --git a/src/mailman/mta/docs/verp.txt b/src/mailman/mta/docs/verp.txt
index 75e608c7a..aa7f27793 100644
--- a/src/mailman/mta/docs/verp.txt
+++ b/src/mailman/mta/docs/verp.txt
@@ -93,8 +93,6 @@ VERPing is only actually done if the metadata requests it.
     To: test@example.com
     Subject: test one
     Message-ID: <aardvark>
-    Sender: test-bounces+aperson=example.com@example.com
-    Errors-To: test-bounces+aperson=example.com@example.com
     X-Peer: ...
     X-MailFrom: test-bounces+aperson=example.com@example.com
     X-RcptTo: aperson@example.com
@@ -105,8 +103,6 @@ VERPing is only actually done if the metadata requests it.
     To: test@example.com
     Subject: test one
     Message-ID: <aardvark>
-    Sender: test-bounces+bperson=example.com@example.com
-    Errors-To: test-bounces+bperson=example.com@example.com
     X-Peer: ...
     X-MailFrom: test-bounces+bperson=example.com@example.com
     X-RcptTo: bperson@example.com
@@ -117,8 +113,6 @@ VERPing is only actually done if the metadata requests it.
     To: test@example.com
     Subject: test one
     Message-ID: <aardvark>
-    Sender: test-bounces+cperson=example.com@example.com
-    Errors-To: test-bounces+cperson=example.com@example.com
     X-Peer: ...
     X-MailFrom: test-bounces+cperson=example.com@example.com
     X-RcptTo: cperson@example.com
diff --git a/src/mailman/queue/docs/outgoing.txt b/src/mailman/queue/docs/outgoing.txt
index cdabdb795..73a9200ef 100644
--- a/src/mailman/queue/docs/outgoing.txt
+++ b/src/mailman/queue/docs/outgoing.txt
@@ -76,8 +76,6 @@ Every recipient got the same copy of the message.
     To: test@example.com
     Subject: My first post
     Message-ID: <first>
-    Sender: test-bounces@example.com
-    Errors-To: test-bounces@example.com
     X-Peer: ...
     X-MailFrom: test-bounces@example.com
     X-RcptTo: cperson@example.com, bperson@example.com, aperson@example.com
@@ -117,7 +115,7 @@ recipients.
     >>> from operator import itemgetter
     >>> def show_headers(messages):
     ...     for message in sorted(messages, key=itemgetter('x-rcptto')):
-    ...         print message['X-RcptTo'], message['Sender']
+    ...         print message['X-RcptTo'], message['X-MailFrom']
 
     >>> show_headers(messages)
     aperson@example.com   test-bounces@example.com