Bug#1063518: console-setup: setupcon: 1386: Syntax error: Missing '))'

[Thorsten Bonow <toto@not-in-kansas-anymore.org>]

> Package: console-setup
> Version: 1.225
> Severity: grave
>
> After the upgrade from 1.223, console-setup.service failed to start 
> due
> to a syntax error in the setupcon script:
>
> ,----
> | $ setupcon
> | /usr/bin/setupcon: 1386: Syntax error: Missing '))'
> `----
>
> It looks like dash does not like the construct in line 907 where 
> there
> is an opening '$((' but the closing parentheses are split.
>
> ,----
> | $ dash << 'EOF'
> | > echo $((true))
> | > echo $((true) )
> | > EOF
> | 0
> | dash: 3: Syntax error: Missing '))'
> | $
> `----

I tried

dash << 'EOF'                                            [15:28:53]
if $( (true) 2>/dev/null); then
 echo "42"
fi
EOF
42

which only works in dash because of the added space between the 
command substitution $(...) and the subshell (...).

Does dash think it has to do arithmetic expansion "$((...))"?

bash and zsh in sh mode accept nesting a subshell within the command 
substitution without an extra space.  In the last version of the 
script, backticks were used, circumventing this issue.

But what's POSIX take on this?  I couldn't find anything.  Is this a 
bug in dash or in setupcon?

Toto

PS: To the proposal of a cleanup: 'checkbashisms' doesn't return any
    errors, but IMHO, at least closing (double) quotes on
    a line of their own should be fixed:

    $ cat /bin/setupcon | grep -n "^\(\"\|'\)$"                
[15:47:07]
    87:'
    145:"
    148:"
    190:"
    193:"
    208:"