Dispatcher::dispatch copies the app list on every request

Status: reasoned from code

lib/Dancer2/Core/Dispatcher.pm:30:

my @apps = @{ $self->apps_psgi };

Flattens the arrayref into a fresh list on every dispatch. Trivial, but it is the hottest line in the file, and the loop below already indexes numerically ($apps[$i], $apps[$i+1]), so it can read through the reference directly:

my $apps = $self->apps_psgi;
...
for ( my $i = 0; $i < @{$apps}; $i += 2 ) {
    my ( $app_name, $app ) = @{$apps}[ $i, $i + 1 ];

Benchmark before and after; the gain will be small and scales with the number of mounted apps.

Read lib/Dancer2/Core/Dispatcher.pm:30 and follow the dispatch loop that indexes the mounted apps. Benchmark the current and changed behavior before and after, checking that dispatching remains unchanged while the per-request list copy is avoided.