🚀 go-pugleaf

Description:
You are doubtless aware of the two different forms of From: lines

    From: $?x$x <$g>$|$g$.
and From: $g $?x($x)$.

infamous for the mistake in the first in Eric Allman's documentation
(he required the '<' '>', while 822 explicitly prohibits them unless
the comment text $x is there.)

This format is required for all mailboxes.

Slightly less obvious is that it is impossible to use "new" format
ie comma seperated addresses, in any case other than the "$x <$g>"
case if there is any possibility of the address being formatted as
an 822 source route...

       @aaa,@bbb,@ccc:user@ddd

--- 3 comma seperated recipients, the first 2 with null mailboxes?
this is a consequence of the code in prescan.

This raises the interesting question of parsing a recipient list
such as:

     To:   @aaa,@bbb,@ccc:user@ddd,@www,@xxx,@yyy:user2@zzz,u3@mmm

which is noted with a flying side-swipe in the comments in the UK2.1
configuration package.   The fixes appended to this message cure the problem,
(and I hope fix the problems noted in UK2.1 --- perhaps the authors
will let us know?).
-- 
Andrew Macpherson         | God bless the King! --- I mean the Faith's Defender
PSI%234237100122::andrew  | God bless (no harm in blessing) the Pretender!
andrew@stl.stc.co.uk      | But who Pretender is, or who the King, ---
...mcvax!ukc!stl!andrew   | God bless us all!  That's quite another thing.

Fix:
*** parseaddr.c	Tue Apr  4 13:25:35 1989
--- parseaddr.oc	Tue Apr  4 11:36:24 1989
***************
*** 258,264 ****
  	register int c;
  	char **avp;
  	bool bslashmode;
- 	bool seencolon;			/* Hack for @d1,@d2:u@d3 */
  	int cmntcnt;
  	int anglecnt;
  	char *tok;
--- 258,263 ----
***************
*** 272,278 ****
  
  	q = pvpbuf;
  	bslashmode = FALSE;
- 	seencolon = FALSE;
  	cmntcnt = 0;
  	anglecnt = 0;
  	avp = av;
--- 271,276 ----
***************
*** 364,371 ****
  				}
  				anglecnt--;
  			}
- 			else if (c == ':')
- 				seencolon = TRUE;
  			else if (delim == ' ' && isspace(c))
  				c = ' ';
  
--- 362,367 ----
***************
*** 373,388 ****
  				continue;
  
  			/* see if this is end of input */
! 			/* The funny expression (delim != ',' || ...) deals
! 			 * with the case of an RFC822 source route, which is
! 			 * of the form @d1,@d2,@d3: prepended to a normal
! 			 * domain address;
! 			 *
! 			 * Andrew Macpherson Tue Apr 4 1989
! 			 * Strange how long some things take to come to light!
! 			 */
! 			if (c == delim && anglecnt <= 0 && state != QST &&
! 			    ( delim != ',' || !(*pvpbuf == '@' && !seencolon)))
  				break;
  
  			newstate = StateTab[state][toktype(c)];
--- 369,375 ----
  				continue;
  
  			/* see if this is end of input */
! 			if (c == delim && anglecnt <= 0 && state != QST)
  				break;
  
  			newstate = StateTab[state][toktype(c)];
***************
*** 413,420 ****
  			}
  			*avp++ = tok;
  		}
! 	} while (c != '\0' && (c != delim || anglecnt > 0 ||
! 		    ( delim == ',' && (*pvpbuf == '@' && !seencolon))));
  	*avp = NULL;
  	DelimChar = --p;
  	if (cmntcnt > 0)
--- 400,406 ----
  			}
  			*avp++ = tok;
  		}
! 	} while (c != '\0' && (c != delim || anglecnt > 0));
  	*avp = NULL;
  	DelimChar = --p;
  	if (cmntcnt > 0)