Re: URL not following some 302 redirects after recent changes

[Chong Yidong]

Richard Stallman <address@hidden> writes:

> Here's one idea.  Instead of setting the sentinel temporarily to nil,
> set it temporarily to `sentinel-temporarily-inhibited'.  That would be
> ignored just as nil is ignored.
>
> On restoring the sentinel, if its current value isn't
> `sentinel-temporarily-inhibited', just discard the old value instead
> of restoring it.
>
> This would prevent recursion just like the current code, but sentinels
> that set the sentinel would work once again.
>
> Does anyone see a problem with this fix?

Only that it's a rather deep change for the current stage of the
release (especially considering that the current behavior of sentinels
has been in place since Emacs 21), but it's your call.  If you like, I
can check in the following patch, which implements this idea (plus the
appropriate doc updates).  I have verified that it solves the bug too.

*** emacs/src/process.c.~1.498.~        2007-01-21 08:39:11.000000000 -0500
--- emacs/src/process.c 2007-02-02 12:04:42.000000000 -0500
***************
*** 152,157 ****
--- 152,158 ----
  Lisp_Object Qrun, Qstop, Qsignal;
  Lisp_Object Qopen, Qclosed, Qconnect, Qfailed, Qlisten;
  Lisp_Object Qlocal, Qipv4, Qdatagram;
+ Lisp_Object Qsentinel_inhibited;
  #ifdef AF_INET6
  Lisp_Object Qipv6;
  #endif
***************
*** 6554,6560 ****
  exec_sentinel_unwind (data)
       Lisp_Object data;
  {
!   XPROCESS (XCAR (data))->sentinel = XCDR (data);
    return Qnil;
  }
  
--- 6555,6563 ----
  exec_sentinel_unwind (data)
       Lisp_Object data;
  {
!   if (EQ (XPROCESS (XCAR (data))->sentinel,
!         Qsentinel_inhibited))
!     XPROCESS (XCAR (data))->sentinel = XCDR (data);
    return Qnil;
  }
  
***************
*** 6592,6600 ****
    if (NILP (sentinel))
      return;
  
!   /* Zilch the sentinel while it's running, to avoid recursive invocations;
!      assure that it gets restored no matter how the sentinel exits.  */
!   p->sentinel = Qnil;
    record_unwind_protect (exec_sentinel_unwind, Fcons (proc, sentinel));
    /* Inhibit quit so that random quits don't screw up a running filter.  */
    specbind (Qinhibit_quit, Qt);
--- 6595,6604 ----
    if (NILP (sentinel))
      return;
  
!   /* Set the sentinel to Qsentinel_inhibited while it's running, to
!      avoid recursive invocations.  It gets restored when the sentinel
!      exits, unless a new sentinel has been set.  */
!   p->sentinel = Qsentinel_inhibited;
    record_unwind_protect (exec_sentinel_unwind, Fcons (proc, sentinel));
    /* Inhibit quit so that random quits don't screw up a running filter.  */
    specbind (Qinhibit_quit, Qt);
***************
*** 7031,7036 ****
--- 7035,7042 ----
    staticpro (&Qlisten);
    Qlocal = intern ("local");
    staticpro (&Qlocal);
+   Qsentinel_inhibited = intern ("sentinel-inhibited");
+   staticpro (&Qsentinel_inhibited);
    Qipv4 = intern ("ipv4");
    staticpro (&Qipv4);
  #ifdef AF_INET6