Path: csiph.com!au2pb.net!usenet.blueworldhosting.com!feeder01.blueworldhosting.com!news.glorb.com!usenet.stanford.edu!not-for-mail
From: Christoph Gysin <christoph.gysin@gmail.com>
Newsgroups: gnu.bash.bug
Subject: Re: command substitution is stripping set -e from options
Date: Tue, 6 Oct 2015 00:37:34 +0300
Lines: 29
Approved: bug-bash@gnu.org
Message-ID: <mailman.476.1444081099.16064.bug-bash@gnu.org>
References: <CADex794C1jOf0wrB298_O4ohAqZghYUdd9DJcuaOvV1dCP5AOQ@mail.gmail.com> <560D83DA.9020405@redhat.com> <CADex795r=oqZ7iv4TxrjUn9coDUnu=PgPngkfRWA1f7EZyohfA@mail.gmail.com> <20151002122925.GK25574@eeg.ccf.org> <CADex797-gWHRzpy=gsdORZtU=Os5Qe6f=LwJ7xJ-N-6oHZdd3w@mail.gmail.com> <20151002132221.GL25574@eeg.ccf.org> <56103208.30406@case.edu>
NNTP-Posting-Host: lists.gnu.org
Mime-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Cc: Greg Wooledge <wooledg@eeg.ccf.org>, bug-bash@gnu.org
To: Chester Ramey <chet.ramey@case.edu>
Envelope-to: bug-bash@gnu.org
In-Reply-To: <56103208.30406@case.edu>
Precedence: list
Xref: csiph.com gnu.bash.bug:11580

> The parent shell (the one that enabled -e) should be the one to make the
> decision about whether or not the shell exits.  The exit status of the
> command substitution doesn't make a difference except in one special case,
> so inheriting errexit and exiting (possibly prematurely) doesn't really
> help the parent decide whether or not to exit.

I'm not sure I fully understand.

The parent shell should be the one to decide if the script is supposed
to abort on any unsuccessful exit status. Command substitution should
not change that. The parent shell decided via set -e that it wants to
exit immediately on error.

> Now, of course, it's been more than 20 years, and backwards compatiblity
> is a concern.

I still think this is a bug, I can't imagine why anyone would set "set
-e" and not want to exit on failing commands inside command
substitution. I think posix mode does the right thing in this regard.

If you don't want to fix this for backwards compatibility, is there
anyway we could change that behaviour explicitly? I.e. with another
option? Avoiding command substitution isn't really an option, and this
essentially disables the whole point of set -e.

Chris
-- 
echo mailto: NOSPAM !#$.'<*>'|sed 's. ..'|tr "<*> !#:2" org@fr33z3