Re: « echo '"\$z' » — differences between dash and bash in POSIX mode irrespective of xpg_echo

[Дилян Палаузов <dilyan.palauzov@xxxxxxxxx>]

Hello,

autoconf was updated to avoid this pitfall:

http://git.savannah.gnu.org/gitweb/?p=autoconf.git;a=commit;h=53c23bb4e1cd8aa35248c73277fa08b7c38a6ad9

Greetings
  Дилян



-----Original Message-----
From: Harald van Dijk <harald@xxxxxxxxxxx>
To: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>, Дилян Палаузов <dilyan.palauzov@xxxxxxxxx>
Cc: dash@xxxxxxxxxxxxxxx
Subject: Re: « echo '"\$z' » — differences between dash and bash in POSIX mode irrespective of xpg_echo
Date: 21/10/24 08:01:53

On 21/10/2024 05:34, Herbert Xu wrote:
> Дилян Палаузов <dilyan.palauzov@xxxxxxxxx> wrote:
> > 
> > I download https://ftp.gnu.org/gnu/gdb/gdb-15.2.tar.xz and run there ./configure . configure has on line 19728
> > 
> >    echo 'cat >>"\$ac_tmp/subs1.awk" <<\\_ACAWK &&' &&
> 
> The issue is that echo(1) with a backslash character is not portable.

This particular use of echo with a backslash character used to work the 
same way across shells and is widely used in configure scripts in a 
large number of packages (specifically: any that use AC_SUBST_FILE). It 
was changed by commit 776424a8 (parser: Add dollar single quote) without 
that commit indicating that this would change; are you really sure this 
should not be viewed as a bug? The impact will be massive.

Cheers,
Harald van Dijk