fix #6305: cli formatter: avoid encoding YAML output twice

YAML::XS::Dump already returns UTF-8 encoded octets, but its output
still got encoded once more. This is a leftover from when the YAML
output was generated by CPAN::Meta::YAML, which returns a character
string.

As a result, all non-ASCII characters got mangled with the 'yaml'
output format, for example a cluster description with a German umlaut
when running:

  pvesh get /cluster/options --output-format yaml

Print the output of YAML::XS::Dump as is, like it is already done for
the 'json' output format, and add a test for the encoding of both.

Fixes: 99d0252 ("properly encode YAML via YAML::XS")
Signed-off-by: Michal Fox <me@dualfroz.com>

src/PVE/CLIFormatter.pm

@@ -380,7 +380,8 @@ sub print_api_result {
     }
 
     if ($format eq 'yaml') {
-        print encode('UTF-8', YAML::XS::Dump($data));
+        # Note: YAML::XS already returns UTF-8 encoded output
+        print YAML::XS::Dump($data);
     } elsif ($format eq 'json') {
         # Note: we always use utf8 encoding for json format
         print to_json($data, { utf8 => 1, allow_nonref => 1, canonical => 1 }) . "\n";

test/format_test.pl

@@ -7,6 +7,7 @@ use lib '../src';
 use PVE::JSONSchema;
 use PVE::CLIFormatter;
 
+use Encode qw(decode);
 use Test::More;
 use Test::MockModule;
 
@@ -53,4 +54,18 @@ foreach my $data (@$render_data) {
     is($actual, $expected, "string format '$renderer_name'");
 }
 
+# test that non-ASCII characters survive the structured output formats
+my $unicode_data = { description => "Erkl\x{e4}rung" };
+for my $format (qw(json yaml)) {
+    open(my $fh, '>', \my $output) or die "failed to open in-memory file - $!\n";
+    my $stdout = select($fh);
+    PVE::CLIFormatter::print_api_result(
+        $unicode_data, undef, undef, { 'output-format' => $format }, {},
+    );
+    select($stdout);
+    close($fh);
+
+    like(decode('UTF-8', $output), qr/Erkl\x{e4}rung/, "output format '$format' is UTF-8 encoded");
+}
+
 done_testing();