Re: [PATCH qemu-server 3/3] removed some unnecessary undef checks.

["Elias Huhsovitz" <e.huhsovitz@proxmox.com>]

Summary
-------
* classify_drive_file() and drive_has_absolute_path() are not prepared
  to handle undef values, and therefore removing the undef checks causes
  a change in behaviour

* commit message should be imperative, e.g., "remove some unnecessary
undef checks"

On Mon Aug 3, 2026 at 2:12 PM CEST, Thomas Ellmenreich wrote:
> Signed-off-by: Thomas Ellmenreich <t.ellmenreich@proxmox.com>
> ---
>  src/PVE/QemuServer.pm | 12 ++++--------
>  1 file changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/src/PVE/QemuServer.pm b/src/PVE/QemuServer.pm
> index 0e998cbe..3141b298 100644
> --- a/src/PVE/QemuServer.pm
> +++ b/src/PVE/QemuServer.pm
> @@ -1818,11 +1818,10 @@ sub destroy_vm {
>              { include_unused => 1 },
>              sub {
>                  my ($ds, $drive) = @_;
> -                return if drive_is_cdrom($drive);
>  
> -                my $volid = $drive->{file};
> -                return if !$volid || drive_has_absolute_path($drive);

I think this might result in an edge case where $drive->{file} can be undef,
causing the underlying function classify_drive_file() that drive_has_absolute_path()
calls, to emit a warning.

To my understanding, classify_drive_file() is currently unpreparted to
receive undef values. I believe a guard clause in classify_drive_file()
resolves this.

e.g., in classify_drive_file:

my ($volid) = @_;
return '' if (!$volid);

> +                return if drive_is_cdrom($drive) || drive_has_absolute_path($drive);
>  
> +                my $volid = $drive->{file};
>                  my $result = eval { PVE::Storage::volume_is_base_and_used($storecfg, $volid) };
>                  # early check, removal of volume will fail later anyway, so warning here is fine
>                  log_warn("failed to check if volume '$volid' is used by linked clones: $@")
> @@ -1839,8 +1838,7 @@ sub destroy_vm {
>          return if drive_is_cdrom($drive, 1);
>  
>          my $volid = $drive->{file};
> -        return if !$volid || drive_has_absolute_path($drive);

same here.

> -        return if $volids->{$volid};
> +        return if drive_has_absolute_path($drive) || $volids->{$volid};
>  
>          my ($path, $owner) = eval { PVE::Storage::path($storecfg, $volid) };
>          log_warn("failed to get path and owner of volume '$volid': $@") if $@;
> @@ -6510,11 +6508,9 @@ my $restore_cleanup_oldconf = sub {
>          sub {
>              my ($ds, $drive) = @_;
>  
> -            return if drive_is_cdrom($drive, 1);
> +            return if drive_is_cdrom($drive, 1) || drive_has_absolute_path($drive);
>  
>              my $volid = $drive->{file};
> -            return if !$volid || drive_has_absolute_path($drive);

same here.

> -
>              my ($path, $owner) = PVE::Storage::path($storecfg, $volid);
>              return if !$path || !$owner || ($owner != $vmid);
>