Bug#896071: debootstrap fails to retrive Release file over https

[David Margerison <deltam@electrosonics.com.au>]

On 21 April 2018 at 21:32, Hideki Yamane <henrich@iijmio-mail.jp> wrote:
>
>  Thanks for the report, and here's a proposal fix.
>
>         [ ! "$VERBOSE" ] && NVSWITCH="-nv"
>         local ret=0
>         if [ "$USE_DEBIANINSTALLER_INTERACTION" ] && [ "$PROGRESS_NEXT" ]; then
> -               wget "$@" 2>&1 >/dev/null | "$PKGDETAILS" "WGET%" "$PROGRESS_NOW" "$PROGRESS_NEXT" "$PROGRESS_END" >&3
> +               wget $@ 2>&1 >/dev/null | "$PKGDETAILS" "WGET%" "$PROGRESS_NOW" "$PROGRESS_NEXT" "$PROGRESS_END" >&3
>                 ret=$?
>         else
> -               wget $NVSWITCH "$@"
> +               wget $NVSWITCH $@
>                 ret=$?
>         fi
>         return $ret

Hi, I have not looked into the actual problem, and I have not run the code,
I have only looked at the patch above, but I offer some patch review comments
in the hope you will find them useful.

The "ret" variable in that function is entirely pointless. The
exitstatus of an if statment
is the exitstatus of the last command executed in the body of the if
statement. And
a bare return command will return the exitstatus of the previous
command executed.

So the below code will behave identically to the unpatched function:

wgetprogress () {
[ ! "$VERBOSE" ] && NVSWITCH="-nv"
if [ "$USE_DEBIANINSTALLER_INTERACTION" ] && [ "$PROGRESS_NEXT" ]; then
    wget "$@" 2>&1 >/dev/null | "$PKGDETAILS" "WGET%" "$PROGRESS_NOW"
"$PROGRESS_NEXT" "$PROGRESS_END" >&3
else
    wget $NVSWITCH "$@"
fi
}

>  "$@" is extracted as '' and wget tries to fetch it and fails,
>  then returns 1.

Regarding the proposed fix, in general using $@ without quotes is fragile.

And I don't understand how changing "$@" to $@ will change the behaviour
of wget. Testing here, both
    wget
and
    wget ''
return exitstatus 1.

To test if the function was given any positional parameters, instead use

if [ $# -eq 0 ] ; then
    echo "There are no parameters"
fi

To test if $@ is empty, use

if [ -z "$*" ] ; then
   echo "All parameters are empty"
fi

But wouldn't it be better to fix the actual problem? If somewhere this
function is called without parameters, then that is where the problem
occurs and so is likely the best place to fix it.