help-bash
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Bash 5.2 SHLVL change and autoconf test failures


From: Chet Ramey
Subject: Re: Bash 5.2 SHLVL change and autoconf test failures
Date: Fri, 30 Sep 2022 09:24:04 -0400
User-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.3.0

On 9/30/22 1:45 AM, Xi Ruoyao wrote:
[Resend because the previous one was rejected due to my bad SPF setting]

On Thu, 2022-09-29 at 11:19 -0400, Chet Ramey wrote:
On 9/28/22 11:25 PM, Xi Ruoyao wrote:
(Sorry for cross posting, but the topic is related to both side)

In Bash-5.2 there is a change:

"ff. Some fixes to how subshells modify $SHLVL."

The single change affects pipelines for which bash optimizes out a
second
fork, so it doesn't decrement $SHLVL twice. It comes from this 2020
report:

https://lists.gnu.org/archive/html/help-bash/2020-10/msg00012.html

(the ssh aspect of this report is a red herring).

Hmm, it makes sense but I can't see how this affects autoconf test suite
(I don't really understand M4).

It might also be the result of a different change that optimizes out some
unnecessary forks; there are a couple of those. I'm not sure why autoconf
is keeping track of SHLVL anyway, unless it's recording state.

--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/




reply via email to

[Prev in Thread] Current Thread [Next in Thread]