Create rule for checking paths inside the require keyword

Author: Bellangelo

src/Rules/Keywords/RequireFileExistsRule.php

@@ -0,0 +1,125 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Keywords;
+
+use PhpParser\Node;
+use PhpParser\Node\Expr\ConstFetch;
+use PhpParser\Node\Expr\Include_;
+use PhpParser\Node\Expr\BinaryOp\Concat;
+use PhpParser\Node\Expr\ClassConstFetch;
+use PhpParser\Node\Identifier;
+use PhpParser\Node\Name;
+use PhpParser\Node\Scalar\MagicConst\Dir;
+use PhpParser\Node\Scalar\String_;
+use PHPStan\Analyser\Scope;
+use PHPStan\Reflection\ReflectionProvider;
+use PHPStan\Rules\Rule;
+use PHPStan\Rules\RuleErrorBuilder;
+
+/**
+ * @implements Rule<Include_>
+ */
+class RequireFileExistsRule implements Rule
+{
+	private ReflectionProvider $reflectionProvider;
+
+	public function __construct(ReflectionProvider $reflectionProvider)
+	{
+		$this->reflectionProvider = $reflectionProvider;
+	}
+
+	public function getNodeType(): string
+	{
+		return Include_::class;
+	}
+
+	public function processNode(Node $node, Scope $scope): array
+	{
+		if ($this->shouldProcessNode($node)) {
+			$filePath = $this->resolveFilePath($node->expr, $scope);
+			if ($filePath !== null && !file_exists($filePath)) {
+				return [
+					RuleErrorBuilder::message(
+						sprintf(
+							'Required file "%s" does not exist.',
+							$filePath
+						)
+					)->build(),
+				];
+			}
+		}
+
+		return [];
+	}
+
+	private function shouldProcessNode(Node $node): bool
+	{
+		return $node instanceof Include_ && (
+				$node->type === Include_::TYPE_REQUIRE
+				|| $node->type === Include_::TYPE_REQUIRE_ONCE
+			);
+	}
+
+	private function resolveFilePath(Node $node, Scope $scope): ?string
+	{
+		if ($node instanceof String_) {
+			return $node->value;
+		}
+
+		if ($node instanceof Dir) {
+			return dirname($scope->getFile());
+		}
+
+		if ($node instanceof ClassConstFetch) {
+			return $this->resolveClassConstant($node);
+		}
+
+		if ($node instanceof ConstFetch) {
+			return $this->resolveConstant($node);
+		}
+
+		if ($node instanceof Concat) {
+			$left = $this->resolveFilePath($node->left, $scope);
+			$right = $this->resolveFilePath($node->right, $scope);
+			if ($left !== null && $right !== null) {
+				return $left . $right;
+			}
+		}
+
+		return null;
+	}
+
+	private function resolveClassConstant(ClassConstFetch $node): ?string
+	{
+		if ($node->class instanceof Name && $node->name instanceof Identifier) {
+			$className = (string) $node->class;
+			$constantName = $node->name->toString();
+
+			if ($this->reflectionProvider->hasClass($className)) {
+				$classReflection = $this->reflectionProvider->getClass($className);
+				if ($classReflection->hasConstant($constantName)) {
+					$constantReflection = $classReflection->getConstant($constantName);
+					$constantValue = $constantReflection->getValue();
+					if (is_string($constantValue)) {
+						return $constantValue;
+					}
+				}
+			}
+		}
+		return null;
+	}
+
+	private function resolveConstant(ConstFetch $node): ?string
+	{
+		if ($node->name instanceof Name) {
+			$constantName = (string) $node->name;
+			if (defined($constantName)) {
+				$constantValue = constant($constantName);
+				if (is_string($constantValue)) {
+					return $constantValue;
+				}
+			}
+		}
+		return null;
+	}
+}