Fix semantics of mu_header_set_value and creation of multipart/alternative MIME

Until now, mu_header_set_value called with replace=0 prepended the header
to the header list, if a header with such name was already present.  This
has been changed.  Now, if the header with the requested name is already
present, its action is as follows:

  1. If repl is 0, return MU_ERR_EXISTS
  2. Otherwise, replace the header with the new value.

If the header is not present, it is appended to the end of the header
list, instead of putting it at the beginning.

This change is incompatible and breaks the tests, that relied on a particular
field ordering.  These are fixed as well.

The use of mu_header_set_value throughout the sources has been revised to
ensure that single-instance headers are never added twice.

This change also facilitates the second part of this commit, which
fixes creation of the multipart/alternative message by the mail utility.

* libmailutils/mailbox/header.c (mu_header_set_value): Fix semantics.
If the replace parameter is not set and the header field with the
given name already exists, return MU_ERR_EXISTS without changing
anything.  If adding new header, append it to the end of the header
list, instead of pushing it to the top.

* configure.ac: Raise shared library revision number.

* libmu_scm/mu_message.c (mu-message-set-header)
(mu-message-set-header-fields): call mu_header_set_value explicitly if
repl is not set.
* libmu_sieve/extensions/moderator.c: Force replace header mode when
needed.
* libmu_sieve/extensions/vacation.c: Likewise.
* mh/mh_init.c (mh_annotate): Prepend the annotation header.
* mh/mhn.c: Force replace header mode when needed.
* mh/repl.c: Likewise.
* mh/send.c: Likewise.

* libmailutils/tests/modmesg01.at: Change expected header order.
* libmailutils/tests/modmesg03.at: Likewise.
* mh/tests/mhn.at: Likewise.
* mh/tests/send.at: Likewise.
* sieve/tests/moderator.at: Likewise.
* sieve/tests/redirect.at: Likewise.
* sieve/tests/reject.at: Likewise.
* sieve/tests/vacation.at: Likewise.

* examples/mta.c (message_finalize): Append X-Authentication-Warning,
instead of setting it.

Make sure Content-Disposition is not set for parts of a multipart/
alternative MIME message.  Some mail readers (notably, yahoo),
misinterpret it.

* libmailutils/mime/attachment.c (at_hdr): Use mu_header_set_value
to set Content-Type and Content-Disposition.
* libmailutils/mime/mime.c (_mime_set_content_type): If the content
type is set to multipart/alternative, remove the Content-Disposition
headers from the message parts.

* mail/send.c (saveatt): Don't set content-disposition for
multipart/alternative, it is now done by the library.
(add_attachments): Warn about ignored headers.
Append only Received and X-* headers, replace others.
(parse_headers): Append headers.
(compose_header_set): Use mu_header_append if COMPOSE_APPEND is requested.
* mail/util.c (util_header_expand): Use mu_header_append.

@@ -32,7 +32,7 @@ AB_INIT
 
 dnl Library versioning
 AC_SUBST(VI_CURRENT,  5)
-AC_SUBST(VI_REVISION, 2)
+AC_SUBST(VI_REVISION, 3)
 AC_SUBST(VI_AGE,      0)
 
 dnl Library paths

@@ -406,7 +406,7 @@ message_finalize (mu_message_t msg, int warn)
 	  return 1;
 	}
       sprintf (warn, "%s %s", pwd->pw_name, SENDER_WARNING);
-      mu_header_set_value (header, "X-Authentication-Warning", warn, 0);
+      mu_header_append (header, "X-Authentication-Warning", warn);
       free (warn);
     }
   

@@ -491,7 +491,6 @@ mu_header_destroy (mu_header_t *ph)
     }
 }
 
-
 int
 mu_header_set_value (mu_header_t header, const char *fn, const char *fv,
 		     int replace)
@@ -511,9 +510,10 @@ mu_header_set_value (mu_header_t header, const char *fn, const char *fv,
   if (fv == NULL && !replace)
     return EINVAL;
 
+  ent = mu_hdrent_find (header, fn, 1);
+  
   if (replace)
     {
-      ent = mu_hdrent_find (header, fn, 1);
       if (ent)
 	{
 	  if (fv == NULL)
@@ -530,12 +530,16 @@ mu_header_set_value (mu_header_t header, const char *fn, const char *fv,
       else if (fv == NULL)
 	return 0;
     }
+  else if (ent)
+    {
+      return MU_ERR_EXISTS;
+    }
   
   ent = mu_hdrent_create (header, NULL,
 			  fn, strlen (fn), fv, strlen (fv));
   if (!ent)
     return ENOMEM;
-  mu_hdrent_prepend (header, ent);
+  mu_hdrent_append (header, ent);
   HEADER_SET_MODIFIED (header);
   return 0;
 }

@@ -83,11 +83,11 @@ at_hdr (mu_header_t hdr, const char *content_type, const char *encoding,
       free (str);
       if (rc)
 	return rc;
-      rc = mu_header_append (hdr, MU_HEADER_CONTENT_TYPE, val);
+      rc = mu_header_set_value (hdr, MU_HEADER_CONTENT_TYPE, val, 1);
       free (val);
     }
   else
-    rc = mu_header_append (hdr, MU_HEADER_CONTENT_TYPE, content_type);
+    rc = mu_header_set_value (hdr, MU_HEADER_CONTENT_TYPE, content_type, 1);
   
   if (rc)
     return rc;
@@ -101,15 +101,16 @@ at_hdr (mu_header_t hdr, const char *content_type, const char *encoding,
       free (str);
       if (rc)
 	return rc;
-      rc = mu_header_append (hdr, MU_HEADER_CONTENT_DISPOSITION, val);
+      rc = mu_header_set_value (hdr, MU_HEADER_CONTENT_DISPOSITION, val, 1);
       free (val);
     }
   else
-    rc = mu_header_append (hdr, MU_HEADER_CONTENT_DISPOSITION, "attachment");
+    rc = mu_header_set_value (hdr, MU_HEADER_CONTENT_DISPOSITION, "attachment",
+			      1);
   if (rc)
     return rc;
-  return mu_header_append (hdr, MU_HEADER_CONTENT_TRANSFER_ENCODING,
-			   encoding ? encoding : "8bit");
+  return mu_header_set_value (hdr, MU_HEADER_CONTENT_TRANSFER_ENCODING,
+			      encoding ? encoding : "8bit", 1);
 }
 
 /* Create in *NEWMSG an empty attachment of given CONTENT_TYPE and ENCODING.

@@ -465,7 +465,21 @@ _mime_set_content_type (mu_mime_t mime)
       if (mime->flags & MU_MIME_MULTIPART_MIXED)
 	content_type = "multipart/mixed; boundary=";
       else
+	{
+	  size_t i;
+
+	  /* Make sure content disposition is not set for alternative
+	     parts */
+	  for (i = 0; i < mime->nmtp_parts; i++)
+	    {
+	      mu_header_t hdr;
+	      
+	      mu_message_get_header (mime->mtp_parts[i]->msg, &hdr);
+	      mu_header_remove (hdr, MU_HEADER_CONTENT_DISPOSITION, 1);
+	    }
+	  
 	  content_type = "multipart/alternative; boundary=";
+	}
       if (mime->boundary == NULL)
 	{
 	  char boundary[128];
@@ -1118,7 +1132,7 @@ mu_mime_get_message (mu_mime_t mime, mu_message_t *msg)
 	    {
 	      mu_message_set_header (mime->msg, mime->hdrs, mime);
 	      mu_header_set_value (mime->hdrs, MU_HEADER_MIME_VERSION, "1.0",
-				   0);
+				   1);
 	      if ((ret = _mime_set_content_type (mime)) == 0)
 		{
 		  if ((ret = mu_body_create (&body, mime->msg)) == 0)

@@ -19,9 +19,9 @@ AT_KEYWORDS([modmesg01])
 
 AT_CHECK([modmesg -a To:gray@localhost -a Subject:test],
 [0],
-[Subject: test
+[From: root
 To: gray@localhost
-From: root
+Subject: test
 
 This is a test message.
 oo

@@ -19,9 +19,9 @@ AT_KEYWORDS([modmesg02])
 
 AT_CHECK([modmesg -a To:gray@localhost -a Subject:test -l 0 -t "That"],
 [0],
-[Subject: test
+[From: root
 To: gray@localhost
-From: root
+Subject: test
 
 That is a test message.
 oo

@@ -289,7 +289,10 @@ SCM_DEFINE_PUBLIC (scm_mu_message_set_header, "mu-message-set-header", 3, 1, 0,
 
   hdr_c = scm_to_locale_string (header);
   val_c = scm_to_locale_string (value);
+  if (repl)
     status = mu_header_set_value (hdr, hdr_c, val_c, repl);
+  else
+    status = mu_header_append (hdr, hdr_c, val_c);
   free (hdr_c);
   free (val_c);
 
@@ -602,7 +605,10 @@ SCM_DEFINE_PUBLIC (scm_mu_message_set_header_fields, "mu-message-set-header-fiel
       SCM_ASSERT (scm_is_string (cdr), cdr, SCM_ARGn, FUNC_NAME);
       hdr_c = scm_to_locale_string (car);
       val_c = scm_to_locale_string (cdr);
+      if (repl)
 	status = mu_header_set_value (hdr, hdr_c, val_c, repl);
+      else
+	status = mu_header_append (hdr, hdr_c, val_c);
       free (hdr_c);
       free (val_c);
       if (status)

@@ -140,6 +140,9 @@ moderator_filter_message (mu_sieve_machine_t mach,
   return rc;
 }
 
+/* Copy the value of the header field FROM from the email header FROM_HDR to
+   the header field TO in the header TO_HDR, replacing the field, if it
+   exists. */
 static int
 copy_header (mu_sieve_machine_t mach,
 	     mu_header_t to_hdr, char *to, mu_header_t from_hdr, char *from)
@@ -153,7 +156,7 @@ copy_header (mu_sieve_machine_t mach,
 		      from, mu_strerror (rc));
       return rc;
     }
-  rc = mu_header_set_value (to_hdr, to, value, 0);
+  rc = mu_header_set_value (to_hdr, to, value, 1);
   return rc;
 }
 
@@ -193,7 +196,7 @@ moderator_discard_message (mu_sieve_machine_t mach, mu_message_t request,
     }
 
   if (from)
-    mu_header_set_value (repl_hdr, MU_HEADER_FROM, from, 0);
+    mu_header_set_value (repl_hdr, MU_HEADER_FROM, from, 1);
 
   mailer = mu_sieve_get_mailer (mach);
   rc = mu_mailer_open (mailer, 0);

@@ -513,10 +513,10 @@ vacation_subject (mu_sieve_machine_t mach,
     
   if (mu_rfc2047_encode (MU_SIEVE_CHARSET, "quoted-printable",
 			 subject, &value))
-    mu_header_set_value (newhdr, MU_HEADER_SUBJECT, subject, 0);
+    mu_header_set_value (newhdr, MU_HEADER_SUBJECT, subject, 1);
   else
     {
-      mu_header_set_value (newhdr, MU_HEADER_SUBJECT, value, 0);
+      mu_header_set_value (newhdr, MU_HEADER_SUBJECT, value, 1);
       free (value);
     }
 
@@ -714,7 +714,7 @@ vacation_reply (mu_sieve_machine_t mach, mu_message_t msg,
     }
   else
     {
-      mu_header_set_value (newhdr, MU_HEADER_TO, to, 0);
+      mu_header_set_value (newhdr, MU_HEADER_TO, to, 1);
 
       val = mu_sieve_get_tag_untyped (mach, "header");
       if (val)

@@ -444,7 +444,8 @@ saveatt (void *item, void *data)
   char *p;
 
   rc = mu_attachment_create (&part, aptr->content_type, aptr->encoding,
-			     aptr->name, aptr->filename);
+			     env->alt ? NULL : aptr->name,
+			     env->alt ? NULL : aptr->filename);
   if (rc)
     {
       mu_error (_("can't create attachment %s: %s"),
@@ -482,8 +483,6 @@ saveatt (void *item, void *data)
       
   mu_mime_get_num_parts	(env->mime, &nparts);
   mu_message_get_header (part, &hdr);
-  if (env->alt)
-    mu_header_set_value (hdr, MU_HEADER_CONTENT_DISPOSITION, "inline", 1);
   mu_rfc2822_msg_id (nparts, &p);
   mu_header_set_value (hdr, MU_HEADER_CONTENT_ID, p, 1);
   free (p);
@@ -640,10 +639,17 @@ add_attachments (compose_env_t *env, mu_message_t *pmsg)
       if (mu_iterator_current_kv (itr, (const void **)&name,
 				  (void**)&value) == 0)
 	{
-	  if (mu_c_strcasecmp (name, MU_HEADER_MIME_VERSION) == 0 ||
+	  if (mu_c_strcasecmp (name, MU_HEADER_RECEIVED) == 0
+	      || mu_c_strncasecmp (name, "X-", 2) == 0)
+	    mu_header_append (outhdr, name, value);
+	  else if (mu_c_strcasecmp (name, MU_HEADER_MIME_VERSION) == 0 ||
 		   mu_c_strncasecmp (name, "Content-", 8) == 0)
+	    {
+	      mu_error (_("%s: not setting header"), name);
 	      continue;
-	  mu_header_append (outhdr, name, value);
+	    }
+	  else
+	    mu_header_set_value (outhdr, name, value, 1);
 	}
     }
   mu_iterator_destroy (&itr);
@@ -826,7 +832,7 @@ parse_headers (mu_stream_t input, compose_env_t *env)
 	      
 	      if (name)
 		{
-		  mu_header_set_value (header, name, value[0] ? value : NULL, 0);
+		  mu_header_append (header, name, value[0] ? value : NULL);
 		  free (name);
 		  free (value);
 		  name = value = NULL;
@@ -856,7 +862,7 @@ parse_headers (mu_stream_t input, compose_env_t *env)
   free (buf);
   if (name)
     {
-      mu_header_set_value (header, name, value, 0);
+      mu_header_append (header, name, value);
       free (name);
       free (value);
     }     
@@ -902,17 +908,27 @@ compose_header_set (compose_env_t *env, const char *name,
   switch (mode)
     {
     case COMPOSE_REPLACE:
+      if (is_address_field (name)
+	  && mailvar_get (NULL, "inplacealiases", mailvar_type_boolean, 0) == 0)
+	{
+	  char *exp = alias_expand (value);
+	  status = mu_header_set_value (env->header, name, exp ? exp : value, 1);
+	  free (exp);
+	}
+      else
+	status = mu_header_set_value (env->header, name, value, 1);
+      break;
+
     case COMPOSE_APPEND:
       if (is_address_field (name)
 	  && mailvar_get (NULL, "inplacealiases", mailvar_type_boolean, 0) == 0)
 	{
 	  char *exp = alias_expand (value);
-	  status = mu_header_set_value (env->header, name, exp ? exp : value,
-					mode);
+	  status = mu_header_append (env->header, name, exp ? exp : value);
 	  free (exp);
 	}
       else
-	status = mu_header_set_value (env->header, name, value, mode);
+	status = mu_header_append (env->header, name, value);
       break;
       
     case COMPOSE_SINGLE_LINE:

@@ -964,7 +964,7 @@ util_header_expand (mu_header_t *phdr)
 	    }
 	}
       else
-	mu_header_set_value (hdr, name, value, 0);
+	mu_header_append (hdr, name, value);
     }
 
   if (errcnt == 0)

@@ -856,11 +856,11 @@ mh_annotate (mu_message_t msg, const char *field, const char *text, int date)
       tm = localtime (&t);
       mu_strftime (datebuf, sizeof datebuf, "%a, %d %b %Y %H:%M:%S %Z", tm);
 
-      mu_header_set_value (hdr, field, datebuf, 0);
+      mu_header_prepend (hdr, field, datebuf);
     }
 
   if (text)
-    mu_header_set_value (hdr, field, text, 0);
+    mu_header_prepend (hdr, field, text);
   mu_message_get_attribute (msg, &attr);
   mu_attribute_set_modified (attr);
 }

@@ -1944,7 +1944,7 @@ copy_header (mu_message_t msg, mu_header_t out)
 	  mu_header_sget_field_value (hdr, i, &value))
 	continue;
 
-      mu_header_set_value (out, name, value, 0);
+      mu_header_append (out, name, value);
     }
 }
 
@@ -2009,7 +2009,7 @@ finish_text_msg (struct compose_env *env, mu_message_t *msg, int ascii)
       mu_message_get_header (newmsg, &hdr);
       copy_header (*msg, hdr);
       mu_header_set_value (hdr, MU_HEADER_CONTENT_TRANSFER_ENCODING,
-			   "quoted-printable", 0);
+			   "quoted-printable", 1);
       
       mu_message_get_body (newmsg, &body);
       mu_body_get_streamref (body, &output);

@@ -247,7 +247,7 @@ make_draft (mu_mailbox_t mbox, int disp, struct mh_whatnow_env *wh)
 	  mu_message_create_copy (&tmp_msg, msg);
 	  mu_message_get_header (tmp_msg, &hdr);
 	  text = mu_opool_finish (fcc_pool, NULL);
-	  mu_header_set_value (hdr, MU_HEADER_FCC, text, 0);
+	  mu_header_set_value (hdr, MU_HEADER_FCC, text, 1);
 	  mh_format (&format, tmp_msg, msgno, width, &buf);
 	  mu_message_destroy (&tmp_msg, NULL);
 	}

@@ -623,7 +623,7 @@ _action_send (void *item, void *data)
 	    mu_header_set_value (hdr, MU_HEADER_X_MAILER,
 				 DEFAULT_X_MAILER, 0);
 	  else if (strcmp (p, "no"))
-	    mu_header_set_value (hdr, MU_HEADER_X_MAILER, p, 0);
+	    mu_header_remove (hdr, MU_HEADER_X_MAILER, 1);
 	}
     }
   

@@ -461,18 +461,18 @@ mimeflt input
 [0],
 [From: gray@example.net
 Subject: Adjacent plain text contexts
-Content-Type: multipart/mixed; boundary="BOUNDARY-1"
 MIME-Version: 1.0
+Content-Type: multipart/mixed; boundary="BOUNDARY-1"
 
 --BOUNDARY-1
-Content-ID: 1
 Content-Type: text/plain
+Content-ID: 1
 
 this is the first content
 
 --BOUNDARY-1
-Content-ID: 2
 Content-Type: text/plain
+Content-ID: 2
 
 and this is the second
 
@@ -499,26 +499,26 @@ mimeflt input
 [0],
 [From: gray@example.net
 Subject: Plaintext content types
-Content-Type: multipart/mixed; boundary="BOUNDARY-1"
 MIME-Version: 1.0
+Content-Type: multipart/mixed; boundary="BOUNDARY-1"
 
 --BOUNDARY-1
-Content-Description: First part
-Content-ID: 1
 Content-Type: text/enriched
+Content-ID: 1
+Content-Description: First part
 
 this content will be tagged as text/enriched
 
 --BOUNDARY-1
-Content-ID: 2
 Content-Type: text/plain
+Content-ID: 2
 
 and this content will be tagged as text/plain
 
 --BOUNDARY-1
-Content-Description: this is a patch
-Content-ID: 3
 Content-Type: application/x-patch
+Content-ID: 3
+Content-Description: this is a patch
 
 and this content will be tagged as application/x-patch
 
@@ -540,8 +540,8 @@ mimeflt input
 [0],
 [From: gray@example.net
 Subject: Sharp at the beginning of a line
-Content-Type: text/plain
 MIME-Version: 1.0
+Content-Type: text/plain
 
 #when sent, this line will start with only one #
 
@@ -562,9 +562,9 @@ mimeflt input
 [0],
 [From: gray@example.net
 Subject: Charset
-Content-Transfer-Encoding: quoted-printable
-Content-Type: text/plain; charset=utf-8
 MIME-Version: 1.0
+Content-Type: text/plain; charset=utf-8
+Content-Transfer-Encoding: quoted-printable
 
 Cze=C5=9B=C4=87
 
@@ -586,9 +586,9 @@ mimeflt input
 [0],
 [From: gray@example.net
 Subject: Forwards
-Content-Description: forwarded messages
-Content-Type: multipart/digest; boundary="BOUNDARY-1"
 MIME-Version: 1.0
+Content-Type: multipart/digest; boundary="BOUNDARY-1"
+Content-Description: forwarded messages
 
 --BOUNDARY-1
 Content-Type: message/rfc822
@@ -713,9 +713,9 @@ mimeflt input
 [0],
 [From: gray@example.net
 Subject: Forwards
-Content-Description: forwarded messages
-Content-Type: multipart/digest; boundary="BOUNDARY-1"
 MIME-Version: 1.0
+Content-Type: multipart/digest; boundary="BOUNDARY-1"
+Content-Description: forwarded messages
 
 --BOUNDARY-1
 Content-Type: message/rfc822
@@ -839,9 +839,9 @@ mimeflt input
 [0],
 [From: gray@example.net
 Subject: Forwards
-Content-Description: forwarded messages
-Content-Type: message/rfc822
 MIME-Version: 1.0
+Content-Type: message/rfc822
+Content-Description: forwarded messages
 
 Received: (from foobar@nonexistent.net)
 	by nonexistent.net id fBSKI8N04906
@@ -915,12 +915,12 @@ mimeflt input
 [0],
 [From: gray@example.net
 Subject: External data
-Content-Type: message/external-body; name="mailutils-3.0.tar.gz"; directory="/gnu/mailutils"; site="ftp.gnu.org"; access-type=anon-ftp; mode="image"
 MIME-Version: 1.0
+Content-Type: message/external-body; name="mailutils-3.0.tar.gz"; directory="/gnu/mailutils"; site="ftp.gnu.org"; access-type=anon-ftp; mode="image"
 
-Content-Description: GNU Mailutils distribution
-Content-ID: 1
 Content-Type: application/octet-stream; type=tar; conversions=compress
+Content-ID: 1
+Content-Description: GNU Mailutils distribution
 
 
 ])
@@ -956,25 +956,25 @@ mimeflt input
 [0],
 [From: gray@example.net
 Subject: Multipart
-Content-Type: multipart/mixed; boundary="BOUNDARY-1"
 MIME-Version: 1.0
+Content-Type: multipart/mixed; boundary="BOUNDARY-1"
 
 --BOUNDARY-1
-Content-ID: 1
 Content-Type: text/plain
+Content-ID: 1
 
 Initial text part.
 
 
 --BOUNDARY-1
-Content-Type: multipart/mixed; boundary="BOUNDARY-2"
 MIME-Version: 1.0
+Content-Type: multipart/mixed; boundary="BOUNDARY-2"
 
 --BOUNDARY-2
-Content-Description: forwarded message
-Content-ID: 2
-Content-Type: message/rfc822
 MIME-Version: 1.0
+Content-Type: message/rfc822
+Content-ID: 2
+Content-Description: forwarded message
 
 Received: (from foobar@nonexistent.net)
 	by nonexistent.net id fBSKI8N04906
@@ -1025,22 +1025,22 @@ And the mome raths outgrabe.
 
 
 --BOUNDARY-2
-Content-ID: 3
 Content-Type: text/plain
+Content-ID: 3
 
 Plain text 1
 
 --BOUNDARY-2
-Content-ID: 4
 Content-Type: text/x-special
+Content-ID: 4
 
 Plain text 2
 
 --BOUNDARY-2
-Content-Transfer-Encoding: base64
-Content-Description: Tar archive
-Content-ID: 5
 Content-Type: application/octet-stream; type=tar
+Content-ID: 5
+Content-Description: Tar archive
+Content-Transfer-Encoding: base64
 
 Tm90IGEgdGFyYmFsbCwgcmVhbGx5Cg==
 --BOUNDARY-2--

@@ -34,11 +34,11 @@ find . -name ,input
 [0],
 [ENVELOPE FROM: mhtester@example.net
 ENVELOPE TO: <gray@example.net>
-   0: X-Mailer: MH (AT_PACKAGE_NAME AT_PACKAGE_VERSION)
-   1: Date: now
-   2: From: mhtester@example.net
-   3: To: <gray@example.net>
-   4: Subject: Send file test
+   0: From: mhtester@example.net
+   1: To: <gray@example.net>
+   2: Subject: Send file test
+   3: Date: now
+   4: X-Mailer: MH (GNU Mailutils 3.2.91)
    5:
    6: Message body
 END OF MESSAGE
@@ -73,21 +73,21 @@ find . -name ',input.[[12]]' | sort
 [0],
 [ENVELOPE FROM: mhtester@example.net
 ENVELOPE TO: <gray@example.net>
-   0: X-Mailer: MH (AT_PACKAGE_NAME AT_PACKAGE_VERSION)
-   1: Date: now
-   2: From: mhtester@example.net
-   3: To: <gray@example.net>
-   4: Subject: Send file test 1
+   0: From: mhtester@example.net
+   1: To: <gray@example.net>
+   2: Subject: Send file test 1
+   3: Date: now
+   4: X-Mailer: MH (GNU Mailutils 3.2.91)
    5:
    6: Message body 1
 END OF MESSAGE
 ENVELOPE FROM: mhtester@example.net
 ENVELOPE TO: <gray@example.org>
-   0: X-Mailer: MH (AT_PACKAGE_NAME AT_PACKAGE_VERSION)
-   1: Date: now
-   2: From: mhtester@example.net
-   3: To: <gray@example.org>
-   4: Subject: Send file test 2
+   0: From: mhtester@example.net
+   1: To: <gray@example.org>
+   2: Subject: Send file test 2
+   3: Date: now
+   4: X-Mailer: MH (AT_PACKAGE_NAME AT_PACKAGE_VERSION)
    5:
    6: Message body 2
 END OF MESSAGE
@@ -112,11 +112,11 @@ cat Mail/,draft
 [0],
 [ENVELOPE FROM: mhtester@example.net
 ENVELOPE TO: <gray@example.net>
-   0: X-Mailer: MH (AT_PACKAGE_NAME AT_PACKAGE_VERSION)
-   1: Date: now
-   2: From: mhtester@example.net
-   3: To: <gray@example.net>
-   4: Subject: Send file test
+   0: From: mhtester@example.net
+   1: To: <gray@example.net>
+   2: Subject: Send file test
+   3: Date: now
+   4: X-Mailer: MH (AT_PACKAGE_NAME AT_PACKAGE_VERSION)
    5:
    6: Message body
 END OF MESSAGE
@@ -147,11 +147,11 @@ sed 's/: Date: .*/: Date: now/' $MTA_DIAG
 [0],
 [ENVELOPE FROM: mhtester@example.net
 ENVELOPE TO: <gray@example.net>
-   0: X-Mailer: MH (AT_PACKAGE_NAME AT_PACKAGE_VERSION)
-   1: Date: now
-   2: From: mhtester@example.net
-   3: To: <gray@example.net>
-   4: Subject: Draftfolder test
+   0: From: mhtester@example.net
+   1: To: <gray@example.net>
+   2: Subject: Draftfolder test
+   3: Date: now
+   4: X-Mailer: MH (AT_PACKAGE_NAME AT_PACKAGE_VERSION)
    5:
    6: Message body
 END OF MESSAGE
@@ -184,11 +184,11 @@ sed 's/: Date: .*/: Date: now/' $MTA_DIAG
 [0],
 [ENVELOPE FROM: mhtester@example.net
 ENVELOPE TO: <gray@example.org>
-   0: X-Mailer: MH (AT_PACKAGE_NAME AT_PACKAGE_VERSION)
-   1: Date: now
-   2: From: mhtester@example.net
-   3: To: <gray@example.org>
-   4: Subject: Draftmessage test
+   0: From: mhtester@example.net
+   1: To: <gray@example.org>
+   2: Subject: Draftmessage test
+   3: Date: now
+   4: X-Mailer: MH (AT_PACKAGE_NAME AT_PACKAGE_VERSION)
    5:
    6: Message body
 END OF MESSAGE

@@ -31,8 +31,8 @@ sed 's/ENVELOPE FROM:.*/ENVELOPE FROM/' ./mta.diag
 ],
 [ENVELOPE FROM
 ENVELOPE TO: <bug-foobar-request@example.org>
-   0: Subject: confirm 7e02c99a82a21a2349291a4f142ee2347bb5fd0b
-   1: To: bug-foobar-request@example.org
+   0: To: bug-foobar-request@example.org
+   1: Subject: confirm 7e02c99a82a21a2349291a4f142ee2347bb5fd0b
    2:
 END OF MESSAGE
 ],
@@ -55,9 +55,9 @@ cat ./mta.diag
 ],
 [ENVELOPE FROM: sergiusz@example.org
 ENVELOPE TO: <bug-foobar-request@example.org>
-   0: From: <sergiusz@example.org>
+   0: To: bug-foobar-request@example.org
    1: Subject: confirm 7e02c99a82a21a2349291a4f142ee2347bb5fd0b
-   2: To: bug-foobar-request@example.org
+   2: From: <sergiusz@example.org>
    3:
 END OF MESSAGE
 ],

@@ -36,11 +36,11 @@ sed 's/ $//' ./mta.diag
 [0],
 [ENVELOPE FROM: coyote@desert.example.org
 ENVELOPE TO: <gray@gnu.org>
-   0: X-Loop-Prevention: foobar@nonexistent.net
-   1: From: coyote@desert.example.org
-   2: To: roadrunner@acme.example.com
-   3: Subject: I have a present for you
-   4: X-Caffeine: C8H10N4O2
+   0: From: coyote@desert.example.org
+   1: To: roadrunner@acme.example.com
+   2: Subject: I have a present for you
+   3: X-Caffeine: C8H10N4O2
+   4: X-Loop-Prevention: foobar@nonexistent.net
    5: 
    6: Look, I'm sorry about the whole anvil thing, and I really
    7: didn't mean to try and drop it on you from the top of the
@@ -55,12 +55,12 @@ ENVELOPE TO: <gray@gnu.org>
 END OF MESSAGE
 ENVELOPE FROM: b1ff@de.res.example.com
 ENVELOPE TO: <gray@gnu.org>
-   0: X-Loop-Prevention: foobar@nonexistent.net
-   1: From: youcouldberich!@reply-by-postal-mail.invalid
-   2: To: rube@landru.example.edu
-   3: Subject: $$$ YOU, TOO, CAN BE A MILLIONAIRE! $$$
-   4: Date: TBD
-   5: X-Number: 0015
+   0: From: youcouldberich!@reply-by-postal-mail.invalid
+   1: To: rube@landru.example.edu
+   2: Subject: $$$ YOU, TOO, CAN BE A MILLIONAIRE! $$$
+   3: Date: TBD
+   4: X-Number: 0015
+   5: X-Loop-Prevention: foobar@nonexistent.net
    6: 
    7: YOU MAY HAVE ALREADY WON TEN MILLION DOLLARS, BUT I DOUBT
    8: IT!  SO JUST POST THIS TO SIX HUNDRED NEWSGROUPS!  IT WILL
@@ -72,15 +72,15 @@ ENVELOPE TO: <gray@gnu.org>
 END OF MESSAGE
 ENVELOPE FROM: bar@dontmailme.org
 ENVELOPE TO: <gray@gnu.org>
-   0: X-Loop-Prevention: foobar@nonexistent.net
-   1: Received: (from bar@dontmailme.org)
-   2: 	by dontmailme.org id fERKR9N16790
-   3: 	for foobar@nonexistent.net; Fri, 28 Dec 2001 22:18:08 +0200
-   4: Date: Fri, 28 Dec 2001 23:28:08 +0200
-   5: From: Bar <bar@dontmailme.org>
-   6: To: Foo Bar <foobar@nonexistent.net>
-   7: Message-Id: <200112232808.fERKR9N16790@dontmailme.org>
-   8: Subject: Coffee
+   0: Received: (from bar@dontmailme.org)
+   1: 	by dontmailme.org id fERKR9N16790
+   2: 	for foobar@nonexistent.net; Fri, 28 Dec 2001 22:18:08 +0200
+   3: Date: Fri, 28 Dec 2001 23:28:08 +0200
+   4: From: Bar <bar@dontmailme.org>
+   5: To: Foo Bar <foobar@nonexistent.net>
+   6: Message-Id: <200112232808.fERKR9N16790@dontmailme.org>
+   7: Subject: Coffee
+   8: X-Loop-Prevention: foobar@nonexistent.net
    9: 
   10: How about some coffee?
 END OF MESSAGE

@@ -55,8 +55,8 @@ sed -f filter.sed ./mta.diag
 [ENVELOPE FROM: MAILER-DAEMON@nonexistent.net
 ENVELOPE TO: <coyote@desert.example.org>
    0: To: coyote@desert.example.org
-   1: Content-Type: multipart/mixed; boundary=(boundary)
-   2: MIME-Version: 1.0
+   1: MIME-Version: 1.0
+   2: Content-Type: multipart/mixed; boundary=(boundary)
    3: 
    4: --(boundary)
    5: Content-Type: text/plain;charset=UTF-8
@@ -104,8 +104,8 @@ END OF MESSAGE
 ENVELOPE FROM: MAILER-DAEMON@nonexistent.net
 ENVELOPE TO: <b1ff@de.res.example.com>
    0: To: b1ff@de.res.example.com
-   1: Content-Type: multipart/mixed; boundary=(boundary)
-   2: MIME-Version: 1.0
+   1: MIME-Version: 1.0
+   2: Content-Type: multipart/mixed; boundary=(boundary)
    3: 
    4: --(boundary)
    5: Content-Type: text/plain;charset=UTF-8
@@ -151,8 +151,8 @@ END OF MESSAGE
 ENVELOPE FROM: MAILER-DAEMON@nonexistent.net
 ENVELOPE TO: <bar@dontmailme.org>
    0: To: bar@dontmailme.org
-   1: Content-Type: multipart/mixed; boundary=(boundary)
-   2: MIME-Version: 1.0
+   1: MIME-Version: 1.0
+   2: Content-Type: multipart/mixed; boundary=(boundary)
    3: 
    4: --(boundary)
    5: Content-Type: text/plain;charset=UTF-8