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From: Oliver Kiddle <opk@zsh.org>
To: Bart Schaefer <schaefer@brasslantern.com>
Cc: Zsh hackers list <zsh-workers@zsh.org>
Subject: Re: Speaking of dangerous referents
Date: Sun, 12 Feb 2023 09:00:04 +0100	[thread overview]
Message-ID: <91776-1676188804.595308@S3xK.VfOi.LVPX> (raw)
In-Reply-To: <CAH+w=7aDtVrTseUGcVSPebA0wzwhsG9ToZDWFARFWePK3KNDyg@mail.gmail.com>

Bart Schaefer wrote:
> % empty=()
> % loop='empty[${(P)loop}]'
> % print ${(P)loop}
> zsh: segmentation fault (core dumped)  zsh -f

And in 51399 on namerefs:
> Circular references hidden inside subscripts end up expanding to empty
> string, as do command substitutions with the NO_EXEC trick.

That surprises me. I can't see any executions occurring. Would making
(P) a little safer by applying the NO_EXEC trick to it too fix that seg
fault. Or did you have a different fix in mind? Are there sane uses to
(P) with nasty stuff like hidden command substitutions. We have (e) and
eval which are at least explicit in their dangers.

If genuine uses surface later (PP) could turn on the dangerous form. Or
you might argue that we should support (PP) for the safe form.

Making (P) safer could be another use for the FUTURE option I suggested
in the final paragraph of 51281 - perhaps very few people (if any) were
still reading at that point so it may have been overlooked.

Oliver


  reply	other threads:[~2023-02-12  8:00 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-06  2:21 [PATCH 1/3]: Add named references Bart Schaefer
2023-02-08  3:45 ` Oliver Kiddle
2023-02-08  4:59   ` Bart Schaefer
2023-02-08 23:16     ` Bart Schaefer
2023-02-09  0:47     ` Oliver Kiddle
2023-02-09  2:01       ` Oliver Kiddle
2023-02-09  5:45         ` Bart Schaefer
2023-02-09  4:49       ` Bart Schaefer
2023-02-09 20:49         ` Oliver Kiddle
2023-02-09 23:07           ` Bart Schaefer
2023-02-11  3:04             ` Bart Schaefer
2023-02-11  3:55               ` Bart Schaefer
2023-02-11  5:36                 ` Speaking of dangerous referents Bart Schaefer
2023-02-12  8:00                   ` Oliver Kiddle [this message]
2023-02-12  8:34                     ` Bart Schaefer
2023-02-11  7:02               ` [PATCH 1/3]: Add named references Oliver Kiddle
2023-02-11  7:45                 ` Bart Schaefer
2023-02-11 23:43                   ` Bart Schaefer
2023-02-11 23:45                     ` Bart Schaefer
2023-02-12  7:38                     ` Oliver Kiddle
2024-02-11  7:00                   ` Stephane Chazelas
2024-02-11 16:14                     ` Bart Schaefer
2024-02-11 16:42                       ` Bart Schaefer
2024-02-18  3:26                       ` Up-scope named references, vs. ksh Bart Schaefer
2024-02-20 21:05                         ` Stephane Chazelas
2024-02-20 22:30                           ` Bart Schaefer
2024-02-21 20:12                             ` Stephane Chazelas
2024-02-29  5:16                               ` Bart Schaefer
2024-03-01 18:22                                 ` Stephane Chazelas
2024-03-01 20:34                                   ` Bart Schaefer
2024-03-02  7:29                                     ` Bart Schaefer
2024-03-02 23:55                                       ` [PATCH] "typeset -nu" (was Re: Up-scope named references, vs. ksh) Bart Schaefer
2024-03-01 23:28                                   ` Up-scope named references, vs. ksh Bart Schaefer
2024-03-03 13:44                                     ` Stephane Chazelas
2024-03-03 19:04                                       ` Bart Schaefer
2024-03-03 20:27                                         ` Stephane Chazelas
2024-03-03 22:58                                           ` Bart Schaefer
2024-03-04 19:59                                             ` Stephane Chazelas
2024-03-05  1:05                                             ` Oliver Kiddle
2024-03-05  2:53                                               ` Bart Schaefer
2024-03-05  5:43                                                 ` Mikael Magnusson
2024-03-05  6:30                                                   ` Stephane Chazelas
2024-03-06  5:04                                                     ` [PATCH] local vs. nameref scoping (was Re: Up-scope named references, vs. ksh) Bart Schaefer
2023-02-12  9:02             ` [PATCH 1/3]: Add named references Oliver Kiddle
2023-02-12 18:59               ` Bart Schaefer
2023-02-12 19:45                 ` PM_* flags in zsh.h (was Re: [PATCH 1/3]: Add named references) Bart Schaefer
2023-02-12 21:01                   ` Oliver Kiddle
2023-02-12 22:54                 ` [PATCH 1/3]: Add named references Oliver Kiddle

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