From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Alan Mackenzie Newsgroups: gmane.emacs.bugs Subject: bug#54079: 29.0.50; Method dispatching eratically fails Date: Wed, 9 Mar 2022 20:32:59 +0000 Message-ID: References: <87o82ypfxz.fsf@web.de> <875youbhbu.fsf@web.de> <87k0d7257t.fsf@web.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="4032"; mail-complaints-to="usenet@ciao.gmane.io" Cc: Michael Heerdegen , Lars Ingebrigtsen , 54079@debbugs.gnu.org To: Stefan Monnier Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Wed Mar 09 21:34:12 2022 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nS30d-0000sC-Lf for geb-bug-gnu-emacs@m.gmane-mx.org; Wed, 09 Mar 2022 21:34:11 +0100 Original-Received: from localhost ([::1]:40498 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nS30c-0002Z7-7y for geb-bug-gnu-emacs@m.gmane-mx.org; Wed, 09 Mar 2022 15:34:10 -0500 Original-Received: from eggs.gnu.org ([209.51.188.92]:35202) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nS30V-0002Yy-KE for bug-gnu-emacs@gnu.org; Wed, 09 Mar 2022 15:34:03 -0500 Original-Received: from debbugs.gnu.org ([209.51.188.43]:38723) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1nS30U-0000dR-Pb for bug-gnu-emacs@gnu.org; Wed, 09 Mar 2022 15:34:03 -0500 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1nS30U-0008NA-9E for bug-gnu-emacs@gnu.org; Wed, 09 Mar 2022 15:34:02 -0500 X-Loop: help-debbugs@gnu.org Resent-From: Alan Mackenzie Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Wed, 09 Mar 2022 20:34:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 54079 X-GNU-PR-Package: emacs Original-Received: via spool by 54079-submit@debbugs.gnu.org id=B54079.164685798932112 (code B ref 54079); Wed, 09 Mar 2022 20:34:02 +0000 Original-Received: (at 54079) by debbugs.gnu.org; 9 Mar 2022 20:33:09 +0000 Original-Received: from localhost ([127.0.0.1]:60853 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1nS2zc-0008Ls-JU for submit@debbugs.gnu.org; Wed, 09 Mar 2022 15:33:08 -0500 Original-Received: from colin.muc.de ([193.149.48.1]:45175 helo=mail.muc.de) by debbugs.gnu.org with smtp (Exim 4.84_2) (envelope-from ) id 1nS2za-0008LN-LW for 54079@debbugs.gnu.org; Wed, 09 Mar 2022 15:33:07 -0500 Original-Received: (qmail 22385 invoked by uid 3782); 9 Mar 2022 20:32:59 -0000 Original-Received: from acm.muc.de (p4fe15624.dip0.t-ipconnect.de [79.225.86.36]) (using STARTTLS) by colin.muc.de (tmda-ofmipd) with ESMTP; Wed, 09 Mar 2022 21:32:59 +0100 Original-Received: (qmail 8990 invoked by uid 1000); 9 Mar 2022 20:32:59 -0000 Content-Disposition: inline In-Reply-To: X-Submission-Agent: TMDA/1.3.x (Ph3nix) X-Primary-Address: acm@muc.de X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.io gmane.emacs.bugs:228174 Archived-At: Hello, Stefan. On Wed, Mar 09, 2022 at 13:06:11 -0500, Stefan Monnier wrote: > >> I don't understand the scenario you're thinking of. > >> Are you thinking of something like `(eval-when-compile (byte-compile ...))? > > Yes. > >> Does that ever happen in real life? > > Probably exceedingly seldomly. > > What's to be gained by not catering to this unusual case? What do we > > lose? > We lose making it work right for the 99% other cases that *do* occur? How would it not work right for such a case? Can you give an example? > >> >> And why bother stripping the result of `byte-compile-eval`? > >> > Because it might be the result of evaluating a defun (or defvar or > >> > defconst). > >> AFAIK sympos should only appear within the compiler pipeline between the > >> "read" and the "emit resulting bytecode". They may be passed to various > >> functions and macros along the way, but I can't think of any scenario > >> where they'd end up returned by `(byte-compile-)eval`. > >> > This was the situation which gave rise to the bug. > >> Could you give some details about how it played out? > >> [ Either here or as a comment in the code. ] > > Michael byte compiled cl-generic.el. This created cl-generic.elc > > correctly, but also left uncompiled forms in the function cells of the > > symbols defun'd inside an eval-{when,and}-compile. These forms > > contained symbols with positions. > Hmm... we're talking about stripping the result of `byte-compile-eval`. > This function is only used for `eval-when-compile`, not `eval-and-compile`. > And nothing in your above description indicates that the sympos appeared > in the resulting value of `eval-when-compile` (as opposed to appearing > in the slot of functions and variables that were set during the course > of the evaluation). OK, sorry, I was mistaken. These forms with SWPs arose from evan-AND-compile, which doesn't use byte-compile-eval. > >> >> Fundamentally, `eval` should always strip before doing its job. > >> > Except when what it's evaluating is a defun, defmacrro, defsubst, etc. > >> Why? > > Because that evaluated form might later be byte compiled, and the SWPs > > will be needed for that. > I don't understand the scenario you're thinking of. > Are thinking of a case like: > - something causes the execution of (eval '(defun foo ...)) > - the user types `M-x byte-compile RET foo RET` Sorry again, I've lost the thread here. Weren't we talking about eval-{when,and}-compile, not eval? Inside these two special forms, we should preserve the SWPs as long as possible (i.e. as long as they won't cause any errors). > If so, then: > - I don't think we should care about this case because it's extremely > rare and fundamentally broken (the symbol's function cell contains > a function *value* (i.e. a closure) and not a function's source code, > so in general we need `byte-compile--reify-function` which implements > a heuristic to go back to something like a source form, which can > break in various ways in corner cases). Really? After evaluating a defun, etc., we have a lisp form in the function cell, which may be a closure. The function byte-compile compiles an arbitrary form, doesn't it? > - If we don't strip before calling the `M-x byte-compile` then the code > may/will bisbehave because of the presence of the sympos. How? byte-compile is designed to use SWPs. > Stefan -- Alan Mackenzie (Nuremberg, Germany).