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From: Alexander Reintzsch <Alexander.Reintzsch@netsystem.de>
Newsgroups: gnu.bash.bug
Subject: Misbehavior with constants and bash script
Date: Mon, 19 Nov 2018 21:44:38 +0000
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Hello,=0A=
=0A=
I think I have found some unexpected behavior related to constants in=0A=
bash scripts. Here is a bash script as a short proof of concept.=0A=
=0A=
#!/bin/bash=0A=
function foo=0A=
{=0A=
        echo "A"=0A=
        declare -r vconst=3D"I am fixed."=0A=
        echo "B"=0A=
        declare vconst=3D"new value"=0A=
        echo "C"=0A=
        unset vconst=0A=
        echo "D"=0A=
        vconst=3D"new value"=0A=
        echo "E" # not executed=0A=
}=0A=
=0A=
function bar=0A=
{=0A=
        echo "before foo"=0A=
        foo=0A=
        echo "after foo" # not executed=0A=
}=0A=
=0A=
function buzz=0A=
{=0A=
        echo "before bar"=0A=
        bar=0A=
        echo "after bar" # not executed=0A=
}=0A=
=0A=
foo=0A=
bar=0A=
buzz=0A=
echo "the last line"=0A=
=0A=
Usually bash scripts continue with the next command if they face an error w=
ith one command=0A=
but this script shows some weird behavior. It exits all the functions=0A=
it has called without executing the remaining commands and the continues=0A=
to run in the top scope of the script.=0A=
=0A=
This only happens when a constant declared with=0A=
declare -r myConst=3D"myConstantValue"=0A=
is attempted to be redefined using=0A=
myConst=3D"new value"=0A=
but not with=0A=
declare myConst=3D"new value"=0A=
=0A=
This behavior doesn't seem right.=0A=
=0A=
I have tried this on Ubuntu 16.04 LTS with bash version=0A=
GNU bash, Version 4.3.48(1)-release (x86_64-pc-linux-gnu)=0A=
=0A=
Cheers,=0A=
Alex=