Date: Tue, 27 Dec 2011 13:36:36 -0800 From: Devin Teske <devin.teske@fisglobal.com> To: "'Maxim Khitrov'" <max@mxcrypt.com>, "'FreeBSD'" <freebsd-questions@freebsd.org> Subject: RE: Unexpected sh behavior with EXIT trap and errexit Message-ID: <029f01ccc4df$9cca8190$d65f84b0$@fisglobal.com> In-Reply-To: <CAJcQMWcR9dUqv5fUifEk7r0qN55RJvTnoX2Os3NQqHaghtZ9QA@mail.gmail.com> References: <CAJcQMWcR9dUqv5fUifEk7r0qN55RJvTnoX2Os3NQqHaghtZ9QA@mail.gmail.com>
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> -----Original Message-----
> From: owner-freebsd-questions@freebsd.org [mailto:owner-freebsd-
> questions@freebsd.org] On Behalf Of Maxim Khitrov
> Sent: Tuesday, December 27, 2011 12:25 PM
> To: FreeBSD
> Subject: Unexpected sh behavior with EXIT trap and errexit
>=20
> Can anyone explain this behavior (FreeBSD 9.0-RC3 amd64):
>=20
> Script:
> ----
> #!/bin/sh
>=20
> cleanup()
> {
> echo 'first'
> echo 'second'
> }
>=20
> fail() { return 42; }
>=20
> trap cleanup EXIT
> set -o errexit
> fail
> ----
>=20
> Output:
> ----
> first
> ----
>=20
If you change to:
fail() { false; }
Then the outcome is what you expect (both lines come out).
ASIDE: It appears that it's nothing to do with echo, stdout, or anything ot=
her than the fact that only the first command of the cleanup routine is cal=
led.
>From sh(1) regarding errexit:
"If a shell function is executed and its exit status is explicitly tested, =
all commands of the function are considered to be tested as well."
The exact meaning of which escapes me at the moment, but I'm lead to believ=
e that this explanation somehow plays a role in what we're witnessing with =
your sample.
It may be a bug, it may not. What's interesting in the sample is that the "=
return 42" is a valid command that succeeds while the function itself does =
not.
HTH,
Devin
> Now comment out 'set -o errexit', replace 'fail' with 'fail || exit'
> (which should be equivalent to using errexit), and run again.
>=20
> Output:
> ----
> first
> second
> ----
>=20
> Am I doing something stupid or is this a bug? Bash prints out the same
> (second) output for both versions of the code.
>=20
> - Max
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