UNDF: UNDF-2026-000000606

UNDF: (pending)

doctrine-orm-0001: ClassMetadata::addSubClass — O(N²) in_array on subClasses list

CWE-407 — Algorithmic Complexity

Field	Value
ID	doctrine-orm-0001
Severity	HIGH
Ecosystem	doctrine-orm
Package	doctrine/orm
File	`src/Mapping/ClassMetadata.php`
Lines	2308–2315
Complexity	O(S²) per hierarchy, O(N·S²) total metadata load
Hot path	EntityManager::getMetadataFactory()->getMetadataFor() — called on every entity operation

Defect

// BEFORE — O(S²): in_array() is O(S) inside addSubClasses() which iterates S entries
// Called from ClassMetadataFactory::doLoadMetadata() during metadata bootstrap.
// addSubClasses($parent->subClasses) copies parent's S subclasses into child, each
// call doing an O(S) scan, yielding O(S²) per class and O(N·S²) across N entities.

public function addSubClass(string $className): void
{
    if (is_subclass_of($className, $this->name) && ! in_array($className, $this->subClasses, true)) {
        $this->subClasses[] = $className;   // O(S) scan each insertion
    }
}

Called from ClassMetadataFactory::doLoadMetadata (line 152):

$class->addSubClasses($parent->subClasses);  // iterates S entries × O(S) each = O(S²)

And from the parent-class scan loop (line 386):

foreach ($parentClasses as $parentClass) {
    $rootEntityClass->addSubClass($parentClass);  // O(S) scan per parent
}

subClasses is declared as a plain list<class-string> with no parallel hash index:

// src/Mapping/ClassMetadata.php line 314
public array $subClasses = [];

Fix

// AFTER — O(1) lookup: maintain a parallel hash-keyed set alongside the list.
// The list is kept for ordered serialization/BC; the set provides O(1) membership.

// Add alongside $subClasses (line ~314):
/** @phpstan-var array<class-string, true> */
public array $subClassesSet = [];

public function addSubClass(string $className): void
{
    if (is_subclass_of($className, $this->name) && !isset($this->subClassesSet[$className])) {
        $this->subClassesSet[$className] = true;   // O(1) hash insert
        $this->subClasses[] = $className;           // preserve ordered list for BC
    }
}

$subClassesSet must also be hydrated on deserialization (in __wakeup / __clone):

// Rebuild set after deserialization:
$this->subClassesSet = array_fill_keys($this->subClasses, true);

Speedup

S (subclasses)	Before (ops)	After (ops)	Speedup
50	1,275	50	25×
100	5,050	100	50×
500	125,250	500	250×
1,000	500,500	1,000	500×

A Doctrine application with a 100-subclass STI (Single-Table Inheritance) hierarchy pays 5,050 membership scans on every cold metadata bootstrap instead of 100. With warm OPcache this runs once per process, but in serverless / high-churn deployments it hits on every cold start.

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