Add Twig template exists rule

extension.neon

@@ -11,6 +11,7 @@ parameters:
 		constantHassers: true
 		console_application_loader: null
 		consoleApplicationLoader: null
+		twigTemplateDirectories: []
 	featureToggles:
 		skipCheckGenericClasses:
 			- Symfony\Component\Form\AbstractType
@@ -115,6 +116,7 @@ parametersSchema:
 		constantHassers: bool()
 		console_application_loader: schema(string(), nullable())
 		consoleApplicationLoader: schema(string(), nullable())
+		twigTemplateDirectories: arrayOf(schema(string(), nullable()))
 	])
 
 services:
@@ -365,3 +367,10 @@ services:
 	-
 		factory: PHPStan\Type\Symfony\ExtensionGetConfigurationReturnTypeExtension
 		tags: [phpstan.broker.dynamicMethodReturnTypeExtension]
+
+	-
+		class: PHPStan\Rules\Symfony\TwigTemplateExistsRule
+		arguments:
+			twigTemplateDirectories: %symfony.twigTemplateDirectories%
+		tags:
+			- phpstan.rules.rule

src/Rules/Symfony/TwigTemplateExistsRule.php

@@ -0,0 +1,134 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Symfony;
+
+use PhpParser\Node;
+use PhpParser\Node\Arg;
+use PhpParser\Node\Expr\MethodCall;
+use PhpParser\Node\Expr\Variable;
+use PhpParser\Node\Identifier;
+use PhpParser\Node\Scalar\String_;
+use PHPStan\Analyser\Scope;
+use PHPStan\Rules\Rule;
+use PHPStan\Rules\RuleErrorBuilder;
+use PHPStan\Type\ObjectType;
+use function count;
+use function file_exists;
+use function in_array;
+use function is_string;
+use function preg_match;
+use function sprintf;
+
+/**
+ * @implements Rule<MethodCall>
+ */
+final class TwigTemplateExistsRule implements Rule
+{
+
+	/** @var array<string, string|null> */
+	private $twigTemplateDirectories;
+
+	/** @param array<string, string|null> $twigTemplateDirectories */
+	public function __construct(array $twigTemplateDirectories)
+	{
+		$this->twigTemplateDirectories = $twigTemplateDirectories;
+	}
+
+	public function getNodeType(): string
+	{
+		return MethodCall::class;
+	}
+
+	public function processNode(Node $node, Scope $scope): array
+	{
+		if (count($this->twigTemplateDirectories) === 0) {
+			return [];
+		}
+
+		$templateArg = $this->getTwigTemplateArg($node, $scope);
+
+		if ($templateArg === null) {
+			return [];
+		}
+
+		$templateNames = [];
+
+		if ($templateArg->value instanceof Variable && is_string($templateArg->value->name)) {
+			$varType = $scope->getVariableType($templateArg->value->name);
+
+			foreach ($varType->getConstantStrings() as $constantString) {
+				$templateNames[] = $constantString->getValue();
+			}
+		} elseif ($templateArg->value instanceof String_) {
+			$templateNames[] = $templateArg->value->value;
+		}
+
+		if (count($templateNames) === 0) {
+			return [];
+		}
+
+		$errors = [];
+
+		foreach ($templateNames as $templateName) {
+			if ($this->twigTemplateExists($templateName)) {
+				continue;
+			}
+
+			$errors[] = RuleErrorBuilder::message(sprintf(
+				'Twig template "%s" does not exist.',
+				$templateName
+			))->line($templateArg->getStartLine())->identifier('twig.templateNotFound')->build();
+		}
+
+		return $errors;
+	}
+
+	private function getTwigTemplateArg(MethodCall $node, Scope $scope): ?Arg
+	{
+		if (!$node->name instanceof Identifier) {
+			return null;
+		}
+
+		$argType = $scope->getType($node->var);
+		$methodName = $node->name->name;
+
+		if ((new ObjectType('Symfony\Bundle\FrameworkBundle\Controller\AbstractController'))->isSuperTypeOf($argType)->yes() && in_array($methodName, ['render', 'renderView', 'renderBlockView', 'renderBlock', 'renderForm', 'stream'], true)) {
+			return $node->getArgs()[0] ?? null;
+		}
+
+		if ((new ObjectType('Twig\Environment'))->isSuperTypeOf($argType)->yes() && in_array($methodName, ['render', 'display', 'load'], true)) {
+			return $node->getArgs()[0] ?? null;
+		}
+
+		if ((new ObjectType('Symfony\Bridge\Twig\Mime\TemplatedEmail'))->isSuperTypeOf($argType)->yes() && in_array($methodName, ['htmlTemplate', 'textTemplate'], true)) {
+			return $node->getArgs()[0] ?? null;
+		}
+
+		return null;
+	}
+
+	private function twigTemplateExists(string $templateName): bool
+	{
+		if (preg_match('#^@(.+)\/(.+)$#', $templateName, $matches) === 1) {
+			$templateNamespace = $matches[1];
+			$templateName = $matches[2];
+		} else {
+			$templateNamespace = null;
+		}
+
+		foreach ($this->twigTemplateDirectories as $twigTemplateDirectory => $namespace) {
+			if ($namespace !== $templateNamespace) {
+				continue;
+			}
+
+			$templatePath = $twigTemplateDirectory . '/' . $templateName;
+
+			if (file_exists($templatePath)) {
+				return true;
+			}
+		}
+
+		return false;
+	}
+
+}

tests/Rules/Symfony/ExampleTwigController.php

@@ -0,0 +1,75 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Symfony;
+
+use Symfony\Bridge\Twig\Mime\TemplatedEmail;
+use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Twig\Environment;
+use function rand;
+
+final class ExampleTwigController extends AbstractController
+{
+
+	public function foo(): void
+	{
+		$this->render('foo.html.twig');
+		$this->renderBlock('foo.html.twig');
+		$this->renderBlockView('foo.html.twig');
+		$this->renderForm('foo.html.twig');
+		$this->renderView('foo.html.twig');
+		$this->stream('foo.html.twig');
+
+		$this->render('bar.html.twig');
+		$this->renderBlock('bar.html.twig');
+		$this->renderBlockView('bar.html.twig');
+		$this->renderForm('bar.html.twig');
+		$this->renderView('bar.html.twig');
+		$this->stream('bar.html.twig');
+
+		$twig = new Environment();
+
+		$twig->render('foo.html.twig');
+		$twig->display('foo.html.twig');
+		$twig->load('foo.html.twig');
+
+		$twig->render('bar.html.twig');
+		$twig->display('bar.html.twig');
+		$twig->load('bar.html.twig');
+
+		$templatedEmail = new TemplatedEmail();
+
+		$templatedEmail->htmlTemplate('foo.html.twig');
+		$templatedEmail->textTemplate('foo.html.twig');
+
+		$templatedEmail->textTemplate('bar.html.twig');
+		$templatedEmail->textTemplate('bar.html.twig');
+
+		$name = 'foo.html.twig';
+
+		$this->render($name);
+
+		$name = 'bar.html.twig';
+
+		$this->render($name);
+
+		$name = rand(0, 1) ? 'foo.html.twig' : 'bar.html.twig';
+
+		$this->render($name);
+
+		$name = rand(0, 1) ? 'bar.html.twig' : 'baz.html.twig';
+
+		$this->render($name);
+
+		$this->render($this->getName());
+
+		$this->render('@admin/backend.html.twig');
+		$this->render('@admin/foo.html.twig');
+		$this->render('backend.html.twig');
+	}
+
+	private function getName(): string
+	{
+		return 'baz.html.twig';
+	}
+
+}

tests/Rules/Symfony/TwigTemplateExistsRuleMoreTemplatesTest.php

@@ -0,0 +1,46 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Symfony;
+
+use PHPStan\Rules\Rule;
+use PHPStan\Testing\RuleTestCase;
+
+/**
+ * @extends RuleTestCase<TwigTemplateExistsRule>
+ */
+final class TwigTemplateExistsRuleMoreTemplatesTest extends RuleTestCase
+{
+
+	protected function getRule(): Rule
+	{
+		return new TwigTemplateExistsRule([
+			__DIR__ . '/twig/templates' => null,
+			__DIR__ . '/twig/admin' => 'admin',
+			__DIR__ . '/twig/user' => null,
+		]);
+	}
+
+	public function testGetArgument(): void
+	{
+		$this->analyse(
+			[
+				__DIR__ . '/ExampleTwigController.php',
+			],
+			[
+				[
+					'Twig template "baz.html.twig" does not exist.',
+					61,
+				],
+				[
+					'Twig template "@admin/foo.html.twig" does not exist.',
+					66,
+				],
+				[
+					'Twig template "backend.html.twig" does not exist.',
+					67,
+				],
+			]
+		);
+	}
+
+}

tests/Rules/Symfony/TwigTemplateExistsRuleNoTemplatesTest.php

@@ -0,0 +1,29 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Symfony;
+
+use PHPStan\Rules\Rule;
+use PHPStan\Testing\RuleTestCase;
+
+/**
+ * @extends RuleTestCase<TwigTemplateExistsRule>
+ */
+final class TwigTemplateExistsRuleNoTemplatesTest extends RuleTestCase
+{
+
+	protected function getRule(): Rule
+	{
+		return new TwigTemplateExistsRule([]);
+	}
+
+	public function testGetArgument(): void
+	{
+		$this->analyse(
+			[
+				__DIR__ . '/ExampleTwigController.php',
+			],
+			[]
+		);
+	}
+
+}