Re: [PATCH] Re: libtool-2.4.2 is fine but libtool-2.4.6 very slow.

On Wednesday 23 of September 2015 16:09:49 Eric Blake wrote:
> On 09/23/2015 03:37 PM, Pavel Raiskup wrote:
> 
> > 
> >>From 5e8a4c5173f1aa0786e8eba15fb07bfe04b83862 Mon Sep 17 00:00:00 2001
> > From: Pavel Raiskup <[email protected]>
> > Date: Fri, 18 Sep 2015 23:17:07 +0200
> > Subject: [PATCH] libtoolize: fix infinite recursion in m4
> > 
> > Some projects use this construct in configure.ac:
> > 
> >   m4_define([version], m4_include([version])
> 
> Missing a )
> 
> The faulty package used:
> 
> m4_define([version], m4_include(version))

Thanks for catching the ')' typo!

> and the infinite recursion occurred _because_ the usage was underquoted.
> But as you wrote things here, you have sufficient quoting that you
> won't trigger infinite recursion.
> You need to drop the second [] for
> this to be an accurate representation of the failure.

I intentionally added the '[ ]' quotes there as that is something which
would look like correct usage, but it still goes to infinite recursion.

The problem is that while defining 'version':

  m4_define([version], m4_include([version]))

The expansion is like 'version => m4_include(version)'.  Then, usage of
'version' goes to infinite recursion.

> >   pkg_version=version
> > 
> > When the m4_include builtin is undefined (as was done in
> > libtoolize and extract-trace scripts), the call to this 'version'
> > macro gone to infinite recursion (until ENOMEM).  So rather
> 
> s/gone to infinite/enters an infinite/
> 
> > re-define all potentially dangerous macros by empty strings,
> > suggested by Eric Blake.
> > 
> > While we are on it, merge the macro-"blacklist" with similar list
> > implemented in gettext, except the 'm4_esyscmd'.  It's kept
> 
> s/except the/except for/
> 
> > defined because we already trace AC_INIT macro for package
> > version, while it is often specified by
> > m4_esyscmd(git-version-gen).  Similarly to m4_include, m4_esyscmd
> > might be opt-in-blacklisted in future.
> > 
> > References:
> > http://lists.gnu.org/archive/html/libtool/2015-09/msg00000.html
> > https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=764580
> > 
> 
> With the commit message touched up, it looks okay to me.

I'll fix the typos, thanks!

Pavel