[Icons] `ux:icons:lock` fails

[ameotoko]

Executing ux:icons:lock in my application throws an exception:

You must call one of in() or append() methods before iterating over a Finder.  
                                                                                 

Exception trace:
  at /Users/andrey/Sites/nations/vendor/symfony/finder/Finder.php:667
 Symfony\Component\Finder\Finder->getIterator() at /Users/andrey/Sites/nations/vendor/symfony/ux-icons/src/Twig/IconFinder.php:74
 Symfony\UX\Icons\Twig\IconFinder->templateFiles() at /Users/andrey/Sites/nations/vendor/symfony/ux-icons/src/Twig/IconFinder.php:81
 Symfony\UX\Icons\Twig\IconFinder->templateFiles() at /Users/andrey/Sites/nations/vendor/symfony/ux-icons/src/Twig/IconFinder.php:45
 Symfony\UX\Icons\Twig\IconFinder->icons() at /Users/andrey/Sites/nations/vendor/symfony/ux-icons/src/Command/LockIconsCommand.php:64
 Symfony\UX\Icons\Command\LockIconsCommand->execute() at /Users/andrey/Sites/nations/vendor/symfony/console/Command/Command.php:279
 Symfony\Component\Console\Command\Command->run() at /Users/andrey/Sites/nations/vendor/symfony/console/Application.php:1094
 Symfony\Component\Console\Application->doRunCommand() at /Users/andrey/Sites/nations/vendor/symfony/framework-bundle/Console/Application.php:123
 Symfony\Bundle\FrameworkBundle\Console\Application->doRunCommand() at /Users/andrey/Sites/nations/vendor/symfony/console/Application.php:342
 Symfony\Component\Console\Application->doRun() at /Users/andrey/Sites/nations/vendor/symfony/framework-bundle/Console/Application.php:77
 Symfony\Bundle\FrameworkBundle\Console\Application->doRun() at /Users/andrey/Sites/nations/vendor/symfony/console/Application.php:193
 Symfony\Component\Console\Application->run() at /Users/andrey/Sites/nations/vendor/contao/manager-bundle/bin/contao-console:40
 include() at /Users/andrey/Sites/nations/vendor/bin/contao-console:119

It comes from the Finder call in this method:

ux/src/Icons/src/Twig/IconFinder.php

Lines 67 to 77 in 06b78be

	private function templateFiles(LoaderInterface $loader): iterable
	{
	if ($loader instanceof FilesystemLoader) {
	$paths = [];
	foreach ($loader->getNamespaces() as $namespace) {
	$paths = [...$paths, ...$loader->getPaths($namespace)];
	}
	foreach ((new Finder())->files()->in($paths)->name('*.twig') as $file) {
	yield (string) $file;
	}
	}

The application uses a chain of loaders, last of which is normal Twig\Loader\FilesystemLoader. $loader->getNamespaces() returns empty array, so the $paths is also an empty array, which makes Finder throw.

Adding simple if (!empty($paths)) check fixed it for me, but if it's not correct then I will need some help. This is not a pure Symfony app, but an instance of Contao CMS, which is built on top of Symfony, so may be some configuration needs to be adjusted instead. I am ready to debug it further if somebody points me to the right direction.

[smnandre]

@ameotoko i'd say let's use the occasion to patch / add the default namespace

    private function templateFiles(LoaderInterface $loader): iterable
    {
        if ($loader instanceof FilesystemLoader) {
            $paths = $loader->getPaths();
            foreach ($loader->getNamespaces() as $namespace) {
                $paths = [...$paths, ...$loader->getPaths($namespace)];
            }
            if ($paths) {
                foreach ((new Finder())->files()->in($paths)->name('*.twig') as $file) {
                    yield (string) $file;
                }
            }
        }

        if ($loader instanceof ChainLoader) {
            foreach ($loader->getLoaders() as $subLoader) {
                yield from $this->templateFiles($subLoader);
            }
        }
    }

Would you like to open a PR ?