On Fri, 16 Mar 2018 11:06:07 -0700
David Ahern <[email protected]> wrote:
> On 3/15/18 9:18 AM, Stefano Brivio wrote:
> > trap cleanup EXIT
> >
> > -test_pmtu_vti6_exception
> > +exitcode=0
> > +for name in ${tests}; do
> > + echo "${name}: START"
> > + eval test_${name}
> > + ret=$?
> > + cleanup
> > +
> > + if [ $ret -eq 0 ]; then echo "${name}: FAIL"; exitcode=1
>
> ret = 0 == failure is counterintuitive for Linux.
However, in POSIX shell's AND and OR lists with function calls, a
function returning zero behaves in a similar fashion to a C function
evaluating to true, and a function returning non-zero behaves like a C
function evaluating to false [1]:
a() {
return 0
}
b() {
return 1
}
a && echo this gets printed
b && echo and this does not
This might be equally counter-intuitive for somebody. If one does a lot
of explicit error checking with early returns, my return convention is
also rather practical. E.g. in the setup() function I can do:
eval setup_${arg} && echo " ${arg} not supported" && return 0
instead of:
eval setup_${arg} || { echo " ${arg} not supported" && return 0; }
Still, I went ahead and reversed return codes in the whole script, and
it doesn't look *too* bad with the setup() function from patch 3/9. It
would have been quite ugly earlier.
So I don't have a strong preference. If you still prefer that I reverse
my return codes, I will re-spin the series (and probably I'll need a
first patch that reverses the existing logic, too).
> > + elif [ $ret -eq 1 ]; then echo "${name}: PASS"
> > + elif [ $ret -eq 2 ]; then echo "${name}: SKIP"
>
> I use printf in other scripts so that the pass/fail verdict lineup. e.g.,
> printf " %-60s [PASS]\n" "${name}"
I avoided 'printf' so far because it's not a built-in utility on some
shells (e.g. csh), being a "recent" addition to the POSIX Base
Specifications (issue 4, while 'echo' is from issue 2), and it might be
unavailable on some (embedded?) systems.
I don't have a strong preference about this either. It's a very minor
portability concern vs. a very minor readability improvement, what do
you think?
[1]
http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_09_03_06
--
Stefano
