Re: t5570 trap use in start/stop_git_daemon
- From
Joachim Schmitz <jojo@schmitz-digital.de>
- Date
- Feb 13, 2015, 08:57 UTC
- Message-ID
- <loom.20150213T094712-477@post.gmane.org>
- In-Reply-To
- <20150213080359.GC26775@peff.net>
Jeff King <peff <at> peff.net> writes:
Show 5 quoted lines
> > On Fri, Feb 13, 2015 at 02:44:03AM -0500, Jeff King wrote: > > > On Thu, Feb 12, 2015 at 03:31:12PM -0500, Randall S. Becker wrote: > >
<snip>
Show 50 quoted lines
> Hmm, today I learned something new about ksh. Apparently when you use
> the "function" keyword to define a function like:
>
> function foo {
> trap 'echo trapped' EXIT
> }
> echo before
> foo
> echo after
>
> then the trap runs when the function exits! If you declare the same
> function as:
>
> foo() {
> trap 'echo trapped' EXIT
> }
>
> it behaves differently. POSIX shell does not have the function keyword,
> of course, and we are not using it here. Bash _does_ have the function
> keyword, but seems to behave POSIX-y even when it is present. I.e.,
> running the first script:
>
> $ ksh foo.sh
> before
> trapped
> after
>
> $ bash foo.sh
> before
> after
> trapped
>
> $ dash foo.sh
> foo.sh: 3: foo.sh: function: not found
> foo.sh: 5: foo.sh: Syntax error: "}" unexpected
>
> Switching to the second form, all three produce:
>
> before
> after
> trapped
>
> I don't know if that is all helpful to your bug-tracking or analysis,
> but for whatever reason it looks like your ksh is using localized traps
> for both forms of function. But as far as I know, bash has never behaved
> that way (I just grepped its CHANGES file for mentions of trap and found
> nothing likely).
>
> -Peff
> Both versions produce your first output on our platform
$ ksh foo1.sh before trapped after $ bash foo1.sh before after trapped $ ksh foo2.sh before trapped after $ bash foo2.sh before after trapped $
This might have been one (or even _the_) reason why we picked bash as our SHELL_PATH in config.mak.uname (I don't remember, it's more than 2 years ago), not sure which shell Randall's test used?
bye, Jojo