scripts/download.pl: fix downloads with wget

Several users of wget for downloads (curl is not available in the
system) have reported broken download functionality:

 wget --tries=5 --timeout=20 --output-document=-  https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.142.tar.xz
 http://: Invalid host name.

Thats all happening due to '' was passed as an argument, which got later
expanded to http://.

In the context of a list constructor '' is not nothing, it is an empty
string element.  So fix it by using () as it will yield "nothing" and
thus not introduce an empty string element.

Fixes: #10692
Fixes: 90c6e3aedf16 ("scripts: always check certificates")
Signed-off-by: Jo-Philipp Wich <jo@mein.io> [shellwords() -> ()]
Signed-off-by: Petr Štetiar <ynezz@true.cz>
(cherry picked from commit 50a48faa1b8424e6b4b436b7118fffa2cba14b18)

diff --git a/scripts/download.pl b/scripts/download.pl
index 90a1be4e2614826e7aede95e2b473578b7b26710..33e1e12c1ea8eb223c45edaa6dcddd3c676e16ea 100755 (executable)
--- a/scripts/download.pl
+++ b/scripts/download.pl
@@ -82,8 +82,14 @@ sub download_cmd($) {
        }
 
        return $have_curl
-               ? (qw(curl -f --connect-timeout 20 --retry 5 --location), $check_certificate ? '' : '--insecure', shellwords($ENV{CURL_OPTIONS} || ''), $url)
-               : (qw(wget --tries=5 --timeout=20 --output-document=-), $check_certificate ? '' : '--no-check-certificate', shellwords($ENV{WGET_OPTIONS} || ''), $url)
+               ? (qw(curl -f --connect-timeout 20 --retry 5 --location),
+                       $check_certificate ? () : '--insecure',
+                       shellwords($ENV{CURL_OPTIONS} || ''),
+                       $url)
+               : (qw(wget --tries=5 --timeout=20 --output-document=-),
+                       $check_certificate ? () : '--no-check-certificate',
+                       shellwords($ENV{WGET_OPTIONS} || ''),
+                       $url)
        ;
 }