Fix an issue introduced in #1090: utf8::decode('some string') would…

… not return the string, but a boolean, whether the conversion has succeeded or not. This lead to a cache key which would match all request, no matter what parameters were sent, as the params were not part of the cache key. This in turn lead to LMS always returning the same number of tracks for eg. an artist's various albums.

Let's use `Slim::Utils::Unicode::utf8on()` instead.

Changelog9.html

@@ -31,6 +31,7 @@ <h2><a name="v9.0.1" id="v9.0.1"></a>Version 9.0.1</h2>
 	<ul>
 		<li>Only re-initialize menu settings for connected players - otherwise Analytics considers them "active" due to a prefs change.</li>
 		<li>Fix display of final "Scan done" message in Material skin.</li>
+		<li>Fix track count caching in "titles" query.</li>
 		<li><a href="https://github.com/LMS-Community/slimserver/pull/1235">#1235</a> - Need to utf8Decode album title for new &amp; changed (thanks @darrel-k!)</li>
 		<li><a href="https://github.com/LMS-Community/slimserver/pull/1237">#1237</a> - Fix create table syntax for MySQL (MariaDB) (thanks @JKDingwall!)</li>
 		<li><a href="https://github.com/LMS-Community/slimserver/pull/1238">#1238</a> - Merge multiple works per track into one single work (thanks @darrel-k!)</li>

Slim/Control/Queries.pm

@@ -6327,7 +6327,7 @@ sub _getTagDataForTracks {
 	if ( $count_only || (my $limit = $args->{limit}) ) {
 		# Let the caller worry about the limit values
 
-		my $cacheKey = md5_hex($sql . utf8::decode(join( '', @{$p}, @$w )) . (Slim::Utils::Text::ignoreCase($search, 1) || ''));
+		my $cacheKey = md5_hex($sql . Slim::Utils::Unicode::utf8on(join( ':', @$p, @$w )) . (Slim::Utils::Text::ignoreCase($search, 1) || ''));
 
 		# use short lived cache, as we might be dealing with changing data (eg. playcount)
 		if ( my $cached = $bmfCache{$cacheKey} ) {