On Sat, Oct 10, 2015 at 8:24 PM, Chet Ramey wrote:
> I will consider adding an option to change the behavior of command
> substitution inheriting the -e option, since there doesn't seem to be
> any way to decouple this behavior from posix mode.
I added a patch:
https://savannah.gnu.org/patch/inde
> I know you don't want to hear this, but you really need to stop thinking
> of set -e as "error checking". It is an obsolescent historical anomaly
> that bash is required to support because POSIX specifies it. It isn't
> useful for any purpose, and people who insist on using it are simply
> caus
> I think you're overlooking what I referred to above: that the exit status
> of a command substitution doesn't have any effect on whether the parent's
> command succeeds or fails except in one case: the right-hand-side of an
> assignment statement that is the last assignment in a command consistin
> 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
> Chet can give the definitive answer, but my take is that it's a huge
> surprise to someone writing a function independent of the script, or
> using a function that was written independently of the script. If the
> function does not expect set -e to be in effect (which is not the default,
> and i
> Since it's a function, I would recommend return instead of exit. Also,
> you don't need the $? there. exit (or return) with no arguments will
> retain the exit status of the previous command.
Yes, $? is not needed.
exit or return is equivalent in this case though because of set -e.
> Putting
> Yes, it's how bash has always behaved, at least back to bash-1.14 when
> I stopped looking. Around bash-2.05, it changed to preserve the -e
> option when in Posix mode.
Is there any reason not to preserve it?
> That exception from default bash behavior is documented in the Posix
> Mode section
> Whether e disappears from $- may be unintended, but what IS documented
> is that there are contexts in which set -e has no effect, and when in
> one of those contexts, you cannot re-enable set -e. One such context is
> on the left side of && or ||. Even more non-intuitively, if you have a
> fun
It seems that set -e is stripped from the options ($-) when executing
commands with command substitution:
$ bash -euc 'echo $-; f(){ false; echo $->&2; }; x=$(f)'
ehuBc
huBc
I would expect the shell to exit as soon as it executes 'false'.
Is this intended? Is it documented somewhere?
I'm trying
