cannot reproduce "unknown key value(s)" croaking

[XSven]

perl 5.14.2
IO::Compress 2.206

I am using this function

sub _gunzip_file {
  my ( $filename ) = @_;

  my $gunzip = IO::Uncompress::Gunzip->new( $filename, { Append => 1, MultiStream => 1 } );
  my $buffer = '';
  1 while $gunzip->read( $buffer ) > 0;
  die "gunzip failed: $GunzipError\n" if $GunzipError;

  return $buffer;
}

to gunzip files. Recently the function croaks with the message

Compress::Raw::Zlib::Inflate::new: unknown key value(s) AppendOutput CRC32 ADLER32 at perl5/IO/Uncompress/Adapter/Inflate.pm line 34

Unfortunately until today this happens only once and I was not able to reproduce it even with the same .gz input file that has caused the croaking.

Any idea why it could randomly happen that the key values AppendOutput CRC32 ADLER32 are treated as unknown?

[pmqs]

That is very strange. Looks like somehow the object in $object has got corrupted. Without a way to reproduce it though it will be virtually impossible to fix.

If you get to a point where you can reproduce it, please report it back to me.

[XSven]

I have detected yet another non-reproducible phenomenon

Size magic not implemented at perl5/IO/Uncompress/Base.pm line 386.

On purpose I have not created a separate issue for that. Any idea?

[pmqs]

You are ok keeping the same ticket.

I found this reference to the "Size magic not implemented" error at Perl/perl5#9701. It relates to an internal issue with Perl itself. That could also be the root-cause for the first issue you reported.

I think the only approach for fixing these issues is to upgrade to a newer version of Perl. The version you are using (5.14.2) dates from 2011. The latest version is 5.38.2.