Re: simple function causes BASH to exit when -e in effect

[Kevin Layer]

Bob,

'set -e' is a double-edged sword, for sure, but I'm not sure it creates
more problems than it solves.  Hidden non-zero exits have wasted far more
time, for me, than this little exercise has.

On Sun, Dec 24, 2017 at 11:45 AM, Bob Proulx  wrote:

> Kevin Layer wrote:
> > It took me hours of work to distill this down from a very large and long
> > running script.
>
> > set -eu
>
> Hours and hours of debug time could be saved if people stopped using
> 'set -e' in their programs.  It creates more problems than people
> think it solves.  Do not meddle in the affairs of 'set -e' for it is
> subtle and quick to anger.
>
> Bob
>

Re: simple function causes BASH to exit when -e in effect

[Bob Proulx]

Kevin Layer wrote:
> It took me hours of work to distill this down from a very large and long
> running script.

> set -eu

Hours and hours of debug time could be saved if people stopped using
'set -e' in their programs.  It creates more problems than people
think it solves.  Do not meddle in the affairs of 'set -e' for it is
subtle and quick to anger.

Bob

Re: simple function causes BASH to exit when -e in effect

[Kevin Layer]

The man page says:

The shell does not exit if the command that fails is part  of  the
command list  immediately  following  a  while or until keyword,
part of the test  following  the  if  or  elif  reserved words,
part  of any command executed in a && or || list except the
command following the final  &&  or  ||,  any command  in a
pipeline but the last, or if the command's return value is being
inverted with !.

The fact that [ exits with 1 seems to be covered by the above passage for
-e.


On Fri, Dec 22, 2017 at 10:50 AM, DJ Mills  wrote:

>
>
> On Fri, Dec 22, 2017 at 1:39 PM, Kevin Layer  wrote:
>
>> The bug happens to me on
>> GNU bash, version 4.1.2(2)-release (x86_64-redhat-linux-gnu)
>> and
>> GNU bash, version 4.4.12(1)-release (x86_64-apple-darwin16.4.0)
>>
>> The script is attached, but the function in question is this:
>>
>> function debug1 {
>> [ "$debug" ] && echo "$(date "+%Y-%m-%d %H:%M:%S"): $@"
>> }
>>
>>
> This is expected behavior. When "$debug" is empty, the [ command exits 1.
> That means the && isn't
> run, and the whole function returns with the status of the last run
> command, which is still 1 at this point.
>
>  http://mywiki.wooledge.org/BashFAQ/105
>

Re: simple function causes BASH to exit when -e in effect

[DJ Mills]

On Fri, Dec 22, 2017 at 1:39 PM, Kevin Layer  wrote:

> The bug happens to me on
> GNU bash, version 4.1.2(2)-release (x86_64-redhat-linux-gnu)
> and
> GNU bash, version 4.4.12(1)-release (x86_64-apple-darwin16.4.0)
>
> The script is attached, but the function in question is this:
>
> function debug1 {
> [ "$debug" ] && echo "$(date "+%Y-%m-%d %H:%M:%S"): $@"
> }
>
>
This is expected behavior. When "$debug" is empty, the [ command exits 1.
That means the && isn't
run, and the whole function returns with the status of the last run
command, which is still 1 at this point.

 http://mywiki.wooledge.org/BashFAQ/105

simple function causes BASH to exit when -e in effect

[Kevin Layer]

The bug happens to me on
GNU bash, version 4.1.2(2)-release (x86_64-redhat-linux-gnu)
and
GNU bash, version 4.4.12(1)-release (x86_64-apple-darwin16.4.0)

The script is attached, but the function in question is this:

function debug1 {
[ "$debug" ] && echo "$(date "+%Y-%m-%d %H:%M:%S"): $@"
}

If it is defined like this then no problem exists:

function debug1 {
if [ "$debug" ]; then
echo "$(date "+%Y-%m-%d %H:%M:%S"): $@"
fi
}

nor if it is defined like this:

function debug1 {
[ "$debug" ] && echo "$(date "+%Y-%m-%d %H:%M:%S"): $@"
:
}

When I run the script I see this output:

BEFORE test 2
AFTER test 2
BEFORE test 1

but I expected to see

BEFORE test 2
AFTER test 2
BEFORE test 1
AFTER test 1

It took me hours of work to distill this down from a very large and long
running script.

foo.sh is attached.


foo.sh
Description: Bourne shell script