rector/rules/Php71/Rector/Assign/AssignArrayToStringRector.php

<?php

declare (strict_types=1);
namespace Rector\Php71\Rector\Assign;

use PhpParser\Node;
use PhpParser\Node\Expr;
use PhpParser\Node\Expr\Array_;
use PhpParser\Node\Expr\ArrayDimFetch;
use PhpParser\Node\Expr\Assign;
use PhpParser\Node\Expr\Closure;
use PhpParser\Node\Expr\Variable;
use PhpParser\Node\Scalar\String_;
use PhpParser\Node\Stmt\Class_;
use PhpParser\Node\Stmt\ClassMethod;
use PhpParser\Node\Stmt\Function_;
use PhpParser\Node\Stmt\Namespace_;
use PhpParser\Node\Stmt\Property;
use PhpParser\NodeTraverser;
use PHPStan\Type\UnionType;
use Rector\PhpParser\Node\CustomNode\FileWithoutNamespace;
use Rector\PhpParser\NodeFinder\PropertyFetchFinder;
use Rector\Rector\AbstractRector;
use Rector\ValueObject\PhpVersionFeature;
use Rector\VersionBonding\Contract\MinPhpVersionInterface;
use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
use Symplify\RuleDocGenerator\ValueObject\RuleDefinition;
/**
 * @changelog https://stackoverflow.com/a/41000866/1348344 https://3v4l.org/ABDNv
 *
 * @see \Rector\Tests\Php71\Rector\Assign\AssignArrayToStringRector\AssignArrayToStringRectorTest
 */
final class AssignArrayToStringRector extends AbstractRector implements MinPhpVersionInterface
{
    /**
     * @readonly
     * @var \Rector\PhpParser\NodeFinder\PropertyFetchFinder
     */
    private $propertyFetchFinder;
    public function __construct(PropertyFetchFinder $propertyFetchFinder)
    {
        $this->propertyFetchFinder = $propertyFetchFinder;
    }
    public function provideMinPhpVersion() : int
    {
        return PhpVersionFeature::NO_ASSIGN_ARRAY_TO_STRING;
    }
    public function getRuleDefinition() : RuleDefinition
    {
        return new RuleDefinition('String cannot be turned into array by assignment anymore', [new CodeSample(<<<'CODE_SAMPLE'
$string = '';
$string[] = 1;
CODE_SAMPLE
, <<<'CODE_SAMPLE'
$string = [];
$string[] = 1;
CODE_SAMPLE
)]);
    }
    /**
     * @return array<class-string<Node>>
     */
    public function getNodeTypes() : array
    {
        return [Namespace_::class, FileWithoutNamespace::class, Class_::class, ClassMethod::class, Function_::class, Closure::class];
    }
    /**
     * @param Namespace_|FileWithoutNamespace|Class_|ClassMethod|Function_|Closure $node
     */
    public function refactor(Node $node) : ?Node
    {
        if ($node instanceof Class_) {
            return $this->refactorClass($node);
        }
        if ($node->stmts === null) {
            return null;
        }
        $hasChanged = \false;
        $this->traverseNodesWithCallable($node->stmts, function (Node $subNode) use(&$hasChanged, $node) : ?int {
            if ($subNode instanceof Class_ || $subNode instanceof Function_ || $subNode instanceof Closure) {
                return NodeTraverser::DONT_TRAVERSE_CURRENT_AND_CHILDREN;
            }
            if ($subNode instanceof Assign) {
                $assign = $this->refactorAssign($subNode, $node);
                if ($assign instanceof Assign) {
                    $hasChanged = \true;
                    return null;
                }
            }
            return null;
        });
        if ($hasChanged) {
            return $node;
        }
        return null;
    }
    private function isEmptyString(Expr $expr) : bool
    {
        if (!$expr instanceof String_) {
            return \false;
        }
        return $expr->value === '';
    }
    private function refactorClass(Class_ $class) : ?Class_
    {
        $hasChanged = \false;
        foreach ($class->getProperties() as $property) {
            if (!$this->hasPropertyDefaultEmptyString($property)) {
                continue;
            }
            $arrayDimFetches = $this->propertyFetchFinder->findLocalPropertyArrayDimFetchesAssignsByName($class, $property);
            foreach ($arrayDimFetches as $arrayDimFetch) {
                if ($arrayDimFetch->dim instanceof Expr) {
                    continue;
                }
                $property->props[0]->default = new Array_();
                $hasChanged = \true;
            }
        }
        if ($hasChanged) {
            return $class;
        }
        return null;
    }
    private function hasPropertyDefaultEmptyString(Property $property) : bool
    {
        $defaultExpr = $property->props[0]->default;
        if (!$defaultExpr instanceof Expr) {
            return \false;
        }
        return $this->isEmptyString($defaultExpr);
    }
    /**
     * @return ArrayDimFetch[]
     * @param \PhpParser\Node\Stmt\Namespace_|\Rector\PhpParser\Node\CustomNode\FileWithoutNamespace|\PhpParser\Node\Stmt\ClassMethod|\PhpParser\Node\Stmt\Function_|\PhpParser\Node\Expr\Closure $node
     */
    private function findSameNamedVariableAssigns(Variable $variable, $node) : array
    {
        if ($node->stmts === null) {
            return [];
        }
        $variableName = $this->nodeNameResolver->getName($variable);
        if ($variableName === null) {
            return [];
        }
        $assignedArrayDimFetches = [];
        $this->traverseNodesWithCallable($node->stmts, function (Node $node) use($variable, $variableName, &$assignedArrayDimFetches) {
            if (!$node instanceof Assign) {
                return null;
            }
            if ($this->isReAssignedAsArray($node, $variableName, $variable)) {
                $assignedArrayDimFetches = [];
                return NodeTraverser::STOP_TRAVERSAL;
            }
            if (!$node->var instanceof ArrayDimFetch) {
                return null;
            }
            $arrayDimFetch = $node->var;
            if (!$arrayDimFetch->var instanceof Variable) {
                return null;
            }
            if (!$this->isName($arrayDimFetch->var, $variableName)) {
                return null;
            }
            $assignedArrayDimFetches[] = $arrayDimFetch;
        });
        return $assignedArrayDimFetches;
    }
    private function isReAssignedAsArray(Assign $assign, string $variableName, Variable $variable) : bool
    {
        if ($assign->var instanceof Variable && $this->isName($assign->var, $variableName) && $assign->var->getStartTokenPos() > $variable->getStartTokenPos()) {
            $exprType = $this->nodeTypeResolver->getNativeType($assign->expr);
            if ($exprType->isArray()->yes()) {
                return \true;
            }
        }
        return \false;
    }
    /**
     * @param \PhpParser\Node\Stmt\Namespace_|\Rector\PhpParser\Node\CustomNode\FileWithoutNamespace|\PhpParser\Node\Stmt\ClassMethod|\PhpParser\Node\Stmt\Function_|\PhpParser\Node\Expr\Closure $node
     */
    private function refactorAssign(Assign $assign, $node) : ?Assign
    {
        if (!$assign->var instanceof Variable) {
            return null;
        }
        if (!$this->isEmptyString($assign->expr)) {
            return null;
        }
        $type = $this->nodeTypeResolver->getNativeType($assign->var);
        if ($type->isArray()->yes()) {
            return null;
        }
        if ($type instanceof UnionType) {
            return null;
        }
        $variableAssignArrayDimFetches = $this->findSameNamedVariableAssigns($assign->var, $node);
        $shouldRetype = \false;
        // detect if is part of variable assign?
        foreach ($variableAssignArrayDimFetches as $variableAssignArrayDimFetch) {
            if ($variableAssignArrayDimFetch->dim instanceof Expr) {
                continue;
            }
            $shouldRetype = \true;
            break;
        }
        if (!$shouldRetype) {
            return null;
        }
        $assign->expr = new Array_();
        return $assign;
    }
}