From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: "Drew Adams" Newsgroups: gmane.emacs.devel Subject: RE: [drew.adams@oracle.com: RE: weird defadvicebugwithbyte-compilation] Date: Sun, 11 Dec 2005 22:44:15 -0800 Message-ID: References: NNTP-Posting-Host: main.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Trace: sea.gmane.org 1134370477 10569 80.91.229.2 (12 Dec 2005 06:54:37 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Mon, 12 Dec 2005 06:54:37 +0000 (UTC) Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Mon Dec 12 07:54:36 2005 Return-path: Original-Received: from lists.gnu.org ([199.232.76.165]) by ciao.gmane.org with esmtp (Exim 4.43) id 1ElhZd-0005Me-NN for ged-emacs-devel@m.gmane.org; Mon, 12 Dec 2005 07:54:14 +0100 Original-Received: from localhost ([127.0.0.1] helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1ElhZQ-0007I7-HT for ged-emacs-devel@m.gmane.org; Mon, 12 Dec 2005 01:54:01 -0500 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1ElhQj-0002cc-P4 for emacs-devel@gnu.org; Mon, 12 Dec 2005 01:45:02 -0500 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1ElhQg-0002aI-IA for emacs-devel@gnu.org; Mon, 12 Dec 2005 01:44:59 -0500 Original-Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1ElhQe-0002ZN-Kh for emacs-devel@gnu.org; Mon, 12 Dec 2005 01:44:57 -0500 Original-Received: from [148.87.122.30] (helo=rgminet01.oracle.com) by monty-python.gnu.org with esmtp (TLS-1.0:DHE_RSA_3DES_EDE_CBC_SHA:24) (Exim 4.34) id 1ElhSK-0003XB-F8 for emacs-devel@gnu.org; Mon, 12 Dec 2005 01:46:40 -0500 Original-Received: from rgmsgw300.us.oracle.com (rgmsgw300.us.oracle.com [138.1.186.49]) by rgminet01.oracle.com (Switch-3.1.6/Switch-3.1.6) with ESMTP id jBC6iNnq027919 for ; Sun, 11 Dec 2005 23:44:23 -0700 Original-Received: from rgmsgw300.us.oracle.com (localhost [127.0.0.1]) by rgmsgw300.us.oracle.com (Switch-3.1.7/Switch-3.1.7) with ESMTP id jBC6iNeI004959 for ; Sun, 11 Dec 2005 23:44:23 -0700 Original-Received: from dradamslap (dhcp-amer-csvpn-gw2-141-144-73-217.vpn.oracle.com [141.144.73.217]) by rgmsgw300.us.oracle.com (Switch-3.1.7/Switch-3.1.7) with SMTP id jBC6iLaf004943 (version=TLSv1/SSLv3 cipher=RC4-MD5 bits=128 verify=NO) for ; Sun, 11 Dec 2005 23:44:23 -0700 Original-To: X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.6604 (9.0.2911.0) In-Reply-To: Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1506 X-Brightmail-Tracker: AAAAAQAAAAI= X-Whitelist: TRUE X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:47527 Archived-At: > It does, as far as I can tell. I don't understand all of it, > however, I admit. I still don't understand, for instance: > > 1. why byte-compiling the defadvice in bar.el would eval > my-mode (my-mode does not even appear in bar.el) I think it doesn't eval it, it just sees that my-mode is not bound. The warning says "reference to free variable `my-mode'", see the backtrace. This is a standard warning from the byte compiler, it is meant to help you detect typos in variable names. OK. I was confused because it was the byte-compilation that led ultimately to x-create-frame raising an unbound var error. > 2. why evaling the defadvice in foo.el would eval my-mode > (the BODY of defadvice is not supposed to be quoted) Because defadvice byte-compiles the function it creates on the fly, I guess. But it is only the defadvice in bar.el, not the defadvice in foo.el, that has the keyword `compile'. And even if it does byte-compile foo.el on the fly (for whatever reason), why would it eval my-mode - the body of a defadvice is not supposed to need to be quoted (it is not evaled by defadvice). That is, I don't understand why a byte-compiler warning of a potentially unbound variable would lead to a *Backtrace* being created - a warning is not an error, and even byte-compiler errors (as opposed to warnings) do not result in a *Backtrace*. > 5. why selecting (require 'foo) and doing eval-region does > not manifest the bug, but putting the cursor after > (require 'foo) and doing `C-x C-e' does manifest the bug. Because, by default, eval-expression-debug-on-error is t, and it affects C-x C-e. If I set eval-expression-debug-on-error to nil, Emacs behaves with C-x C-e like it does with eval-region: it doesn't pop up the *Backtrace* buffer in a separate frame, and the bug doesn't happen. Ah - thanks. That makes sense, given your explanation of the bug being manifested in x-create-frame. I don't understand, however, your statement that when the byte compiler tries to display special-buffer *Compile Log* in a separate frame "it hits the problem with the void variable again". What is the "problem with the void variable"? For the byte-compiler it was only a question of displaying a warning, there was no error to be raised. Why would display of *Compile Log* in a separate frame raise an unbound-variable error? Nevermind; I understand now what happened (wrt the unbound var, not the crash bug). I was confused about who was raising the unbound var error, but I see now that x-create-frame was doing so because the menu-enable property evaled it for a menu-bar menu when x-create-frame tried to create the *Compile Log* frame (which has a menu-bar). This makes me wonder now if byte-compiling in defadvice (i.e. on the fly) should display a *Compile Log* buffer at all. I don't know. In any case, that's clearly the cause of the problem here (but not the explanation of the crash bug). I still have a question, however, about how best to use define-minor-mode to define the mode variable so that it can be used in a put 'menu-enable. Is it necessary to do the define-minor-mode before doing the put? I guess so; but in that case, I prefer the old method of defining a minor-mode function and its variable (defcustom) separately. The problem is the same, but I always place variable definitions at the top, and such a defcustom would be defined before the variable was used in the put 'menu-enable. In the new system, I was calling the minor-mode function first thing (in .emacs), to set the variable, but that function couldn't be called until its defining library was loaded, and that meant that the variable wasn't defined when the *Compile Log* was displayed when byte-compiling a defadvice in the file. Moral (for me): Either don't use define-minor-mode at all or use it first thing in a file, before you make any references (even quoted references, like here) to its mode variable. Thanks for helping me understand, and good luck with the crash bug. - Drew