[PATCH manager 0/1] pve8to9: fix package lookup empty result check

[PATCH manager 0/1] pve8to9: fix package lookup empty result check

[Kefu Chai]

I am new to Perl and noticed this while reading the code. I verified the
bug with a small test:

  perl -e '
    my $pkgs = [ grep { 0 } (1,2,3) ];
    print "Defined\n" if defined $pkgs;
    print "Zero\n"    if $pkgs == 0;
  '

Output:
  Defined

'$pkgs == 0' printed nothing -- the array reference is never numerically
zero, so the empty result check silently passed through even when the
grep returned no results.

Kefu Chai (1):
  pve8to9: fix package lookup empty result check

 PVE/CLI/pve8to9.pm | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

-- 
2.47.3

[PATCH manager 1/1] pve8to9: fix package lookup empty result check

[Kefu Chai]

The empty result guard used two conditions that are always false for an
array reference:

  if (!defined $pkgs || $pkgs == 0) {

'$pkgs' from '[grep {...} @list]' is always defined, and '$pkgs == 0'
numifies the reference (memory address), which is never zero. The
diagnostic log_fail message was therefore never emitted when a package
was not found in the version list.

Replace with '!@$pkgs' to correctly test whether the array is empty.

Signed-off-by: Kefu Chai <k.chai@proxmox.com>
---
 PVE/CLI/pve8to9.pm | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/PVE/CLI/pve8to9.pm b/PVE/CLI/pve8to9.pm
index 0c4b2343..afc4785e 100644
--- a/PVE/CLI/pve8to9.pm
+++ b/PVE/CLI/pve8to9.pm
@@ -175,7 +175,7 @@ my $get_pkg = sub {
     }
 
     my $pkgs = [grep { $_->{Package} eq $pkg } @$versions];
-    if (!defined $pkgs || $pkgs == 0) {
+    if (!@$pkgs) {
         log_fail("unable to determine installed $pkg version.");
         return undef;
     } else {
-- 
2.47.3