[DeadCode] Use PHPStan flow analysis for property initialization in RemoveDefaultValueFromAssignedPropertyRector

rules-tests/DeadCode/Rector/Property/RemoveDefaultValueFromAssignedPropertyRector/Fixture/assign_after_throwing_branch.php.inc

@@ -0,0 +1,43 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\Property\RemoveDefaultValueFromAssignedPropertyRector\Fixture;
+
+use RuntimeException;
+
+final class AssignAfterThrowingBranch
+{
+    private ?string $name = null;
+
+    public function __construct(string $name, bool $shouldFail)
+    {
+        if ($shouldFail) {
+            throw new RuntimeException('nope');
+        }
+
+        $this->name = $name;
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\Property\RemoveDefaultValueFromAssignedPropertyRector\Fixture;
+
+use RuntimeException;
+
+final class AssignAfterThrowingBranch
+{
+    private ?string $name;
+
+    public function __construct(string $name, bool $shouldFail)
+    {
+        if ($shouldFail) {
+            throw new RuntimeException('nope');
+        }
+
+        $this->name = $name;
+    }
+}
+
+?>

rules-tests/DeadCode/Rector/Property/RemoveDefaultValueFromAssignedPropertyRector/Fixture/assign_in_if_elseif_else.php.inc

@@ -0,0 +1,43 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\Property\RemoveDefaultValueFromAssignedPropertyRector\Fixture;
+
+final class AssignInIfElseIfElse
+{
+    private ?string $name = null;
+
+    public function __construct(int $type)
+    {
+        if ($type === 1) {
+            $this->name = 'one';
+        } elseif ($type === 2) {
+            $this->name = 'two';
+        } else {
+            $this->name = 'many';
+        }
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\Property\RemoveDefaultValueFromAssignedPropertyRector\Fixture;
+
+final class AssignInIfElseIfElse
+{
+    private ?string $name;
+
+    public function __construct(int $type)
+    {
+        if ($type === 1) {
+            $this->name = 'one';
+        } elseif ($type === 2) {
+            $this->name = 'two';
+        } else {
+            $this->name = 'many';
+        }
+    }
+}
+
+?>

rules-tests/DeadCode/Rector/Property/RemoveDefaultValueFromAssignedPropertyRector/Fixture/assign_in_switch_with_default.php.inc

@@ -0,0 +1,43 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\Property\RemoveDefaultValueFromAssignedPropertyRector\Fixture;
+
+final class AssignInSwitchWithDefault
+{
+    private ?string $name = null;
+
+    public function __construct(int $type)
+    {
+        switch ($type) {
+            case 1:
+                $this->name = 'one';
+                break;
+            default:
+                $this->name = 'many';
+        }
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\Property\RemoveDefaultValueFromAssignedPropertyRector\Fixture;
+
+final class AssignInSwitchWithDefault
+{
+    private ?string $name;
+
+    public function __construct(int $type)
+    {
+        switch ($type) {
+            case 1:
+                $this->name = 'one';
+                break;
+            default:
+                $this->name = 'many';
+        }
+    }
+}
+
+?>

rules-tests/DeadCode/Rector/Property/RemoveDefaultValueFromAssignedPropertyRector/Fixture/return_after_assign.php.inc

@@ -0,0 +1,43 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\Property\RemoveDefaultValueFromAssignedPropertyRector\Fixture;
+
+final class ReturnAfterAssign
+{
+    private ?string $name = null;
+
+    public function __construct(string $name, bool $shouldReturn = false)
+    {
+        $this->name = $name;
+
+        if ($shouldReturn) {
+            return;
+        }
+
+        $this->name = strtoupper($name);
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\Property\RemoveDefaultValueFromAssignedPropertyRector\Fixture;
+
+final class ReturnAfterAssign
+{
+    private ?string $name;
+
+    public function __construct(string $name, bool $shouldReturn = false)
+    {
+        $this->name = $name;
+
+        if ($shouldReturn) {
+            return;
+        }
+
+        $this->name = strtoupper($name);
+    }
+}
+
+?>

rules-tests/DeadCode/Rector/Property/RemoveDefaultValueFromAssignedPropertyRector/Fixture/skip_assign_in_foreach.php.inc

@@ -0,0 +1,18 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\Property\RemoveDefaultValueFromAssignedPropertyRector\Fixture;
+
+final class SkipAssignInForeach
+{
+    private ?string $name = null;
+
+    /**
+     * @param string[] $names
+     */
+    public function __construct(array $names)
+    {
+        foreach ($names as $name) {
+            $this->name = $name;
+        }
+    }
+}

rules-tests/DeadCode/Rector/Property/RemoveDefaultValueFromAssignedPropertyRector/Fixture/skip_assign_inside_closure.php.inc

@@ -0,0 +1,19 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\Property\RemoveDefaultValueFromAssignedPropertyRector\Fixture;
+
+use Closure;
+
+final class SkipAssignInsideClosure
+{
+    private ?string $name = null;
+
+    public Closure $setName;
+
+    public function __construct(string $name)
+    {
+        $this->setName = function () use ($name): void {
+            $this->name = $name;
+        };
+    }
+}

rules-tests/DeadCode/Rector/Property/RemoveDefaultValueFromAssignedPropertyRector/Fixture/skip_assign_only_in_try.php.inc

@@ -0,0 +1,18 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\Property\RemoveDefaultValueFromAssignedPropertyRector\Fixture;
+
+use Throwable;
+
+final class SkipAssignOnlyInTry
+{
+    private ?string $name = null;
+
+    public function __construct(string $name)
+    {
+        try {
+            $this->name = json_encode($name, JSON_THROW_ON_ERROR);
+        } catch (Throwable) {
+        }
+    }
+}

rules-tests/DeadCode/Rector/Property/RemoveDefaultValueFromAssignedPropertyRector/Fixture/skip_assign_reads_default.php.inc

@@ -0,0 +1,13 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\Property\RemoveDefaultValueFromAssignedPropertyRector\Fixture;
+
+final class SkipAssignReadsDefault
+{
+    private int $count = 0;
+
+    public function __construct(int $extra)
+    {
+        $this->count = $this->count + $extra;
+    }
+}

rules-tests/DeadCode/Rector/Property/RemoveDefaultValueFromAssignedPropertyRector/Fixture/skip_assign_via_offset_access.php.inc

@@ -0,0 +1,16 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\Property\RemoveDefaultValueFromAssignedPropertyRector\Fixture;
+
+final class SkipAssignViaOffsetAccess
+{
+    /**
+     * @var array<string, bool>
+     */
+    private array $cachedByName = [];
+
+    public function __construct(string $name)
+    {
+        $this->cachedByName[$name] = true;
+    }
+}

rules/DeadCode/Rector/Property/RemoveDefaultValueFromAssignedPropertyRector.php

@@ -6,9 +6,12 @@
 
 use PhpParser\Node;
 use PhpParser\Node\Expr;
+use PhpParser\Node\Expr\ArrayDimFetch;
+use PhpParser\Node\Expr\Assign;
 use PhpParser\Node\Stmt\Class_;
 use PhpParser\Node\Stmt\ClassMethod;
-use PhpParser\Node\Stmt\Return_;
+use Rector\NodeAnalyzer\AlwaysInitializedPropertyAnalyzer;
+use Rector\NodeAnalyzer\PropertyFetchAnalyzer;
 use Rector\PhpParser\Node\BetterNodeFinder;
 use Rector\Rector\AbstractRector;
 use Rector\TypeDeclaration\AlreadyAssignDetector\ConstructorAssignDetector;
@@ -23,7 +26,9 @@ final class RemoveDefaultValueFromAssignedPropertyRector extends AbstractRector
 {
     public function __construct(
         private readonly ConstructorAssignDetector $constructorAssignDetector,
-        private readonly BetterNodeFinder $betterNodeFinder
+        private readonly BetterNodeFinder $betterNodeFinder,
+        private readonly PropertyFetchAnalyzer $propertyFetchAnalyzer,
+        private readonly AlwaysInitializedPropertyAnalyzer $alwaysInitializedPropertyAnalyzer
     ) {
     }
 
@@ -79,11 +84,6 @@ public function refactor(Node $node): ?Node
             return null;
         }
 
-        // early return can skip the assign, so the default value is still needed
-        if ($this->betterNodeFinder->hasInstancesOfInFunctionLikeScoped($constructClassMethod, Return_::class)) {
-            return null;
-        }
-
         $hasChanged = false;
 
         foreach ($node->getProperties() as $property) {
@@ -102,7 +102,23 @@ public function refactor(Node $node): ?Node
                 }
 
                 $propertyName = $this->getName($propertyProperty);
-                if (! $this->constructorAssignDetector->isPropertyAssigned($node, $propertyName)) {
+
+                // guards against an assign that reads the default value first, e.g. $this->value = $this->value + 1
+                if (! $this->constructorAssignDetector->isPropertyAssignedConditionally($node, $propertyName)) {
+                    continue;
+                }
+
+                // the property must be initialized on every path out of the constructor,
+                // otherwise removing the default value leaves it uninitialized
+                if (! $this->alwaysInitializedPropertyAnalyzer->isAlwaysInitialized(
+                    $constructClassMethod,
+                    $propertyName
+                )) {
+                    continue;
+                }
+
+                // $this->value['key'] = ... writes to the default value, it does not replace it
+                if ($this->isAssignedViaOffsetAccess($constructClassMethod, $propertyName)) {
                     continue;
                 }
 
@@ -117,4 +133,29 @@ public function refactor(Node $node): ?Node
 
         return null;
     }
+
+    private function isAssignedViaOffsetAccess(ClassMethod $constructClassMethod, string $propertyName): bool
+    {
+        $assign = $this->betterNodeFinder->findFirstInFunctionLikeScoped(
+            $constructClassMethod,
+            function (Node $node) use ($propertyName): bool {
+                if (! $node instanceof Assign) {
+                    return false;
+                }
+
+                $assignVar = $node->var;
+                if (! $assignVar instanceof ArrayDimFetch) {
+                    return false;
+                }
+
+                while ($assignVar instanceof ArrayDimFetch) {
+                    $assignVar = $assignVar->var;
+                }
+
+                return $this->propertyFetchAnalyzer->isLocalPropertyFetchName($assignVar, $propertyName);
+            }
+        );
+
+        return $assign instanceof Assign;
+    }
 }