Do not track string keys of an unpacked non-literal expression in DuplicateKeysInLiteralArraysRule (#6635)

Co-authored-by: VincentLanglet <9052536+VincentLanglet@users.noreply.github.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

Author: 3 people

src/Rules/Arrays/DuplicateKeysInLiteralArraysRule.php

@@ -11,9 +11,12 @@
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Type\ArrayUnpackingHelper;
 use PHPStan\Type\Constant\ConstantIntegerType;
+use PHPStan\Type\Type;
+use function array_filter;
 use function array_key_first;
 use function array_keys;
 use function array_search;
+use function array_values;
 use function count;
 use function implode;
 use function is_bool;
@@ -101,6 +104,15 @@ public function processNode(Node $node, Scope $scope): array
 						? $unpackedKeyType->getValue()
 						: max($autoGeneratedIndex, $unpackedKeyType->getValue());
 				}
+
+				// unpacking an expression works like array_merge() - its string keys are
+				// meant to override or to be overridden by the other keys
+				if (!$item->value instanceof Node\Expr\Array_) {
+					$keyTypes = array_values(array_filter(
+						$keyTypes,
+						static fn (Type $keyType): bool => !$keyType->isString()->yes(),
+					));
+				}
 			} elseif ($key === null) {
 				if ($autoGeneratedIndex === false) {
 					continue;

tests/PHPStan/Rules/Arrays/DuplicateKeysInLiteralArraysRuleTest.php

@@ -180,4 +180,35 @@ public function testBug15247Php81(): void
 		]);
 	}
 
+	#[RequiresPhp('>= 8.1.0')]
+	public function testBug15295(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-15295.php'], [
+			[
+				"Array has 2 duplicate keys with value 'start' ('start', 'start').",
+				47,
+			],
+			[
+				"Array has 2 duplicate keys with value 'start' ('start', 'start').",
+				53,
+			],
+			[
+				'Array has 2 duplicate keys with value 0 (0, 0).',
+				59,
+			],
+			[
+				"Array has 2 duplicate keys with value 0 (0, '0').",
+				65,
+			],
+			[
+				"Array has 2 duplicate keys with value 0 (0, '0').",
+				71,
+			],
+			[
+				"Array has 2 duplicate keys with value 0 (0, '0').",
+				88,
+			],
+		]);
+	}
+
 }

tests/PHPStan/Rules/Arrays/data/bug-15295.php

@@ -0,0 +1,89 @@
+<?php // lint >= 8.1
+
+declare(strict_types = 1);
+
+namespace Bug15295;
+
+/** @param array{heading: string, start: float} $section */
+function resetStart(array $section): array
+{
+	return [...$section, 'start' => 0.0];
+}
+
+function resetStartOfLocalVariable(): array
+{
+	$section = ['heading' => 'h', 'start' => 1.0];
+	return [...$section, 'start' => 0.0];
+}
+
+/** @param array{heading: string, start: float} $section */
+function defaultsOverriddenBySpread(array $section): array
+{
+	return ['start' => 0.0, ...$section];
+}
+
+/**
+ * @param array{heading: string, start: float} $a
+ * @param array{start: float} $b
+ */
+function twoSpreads(array $a, array $b): array
+{
+	return [...$a, ...$b];
+}
+
+/** @return array{heading: string, start: float} */
+function getSection(): array
+{
+	return ['heading' => 'h', 'start' => 1.0];
+}
+
+function resetStartOfCall(): array
+{
+	return [...getSection(), 'start' => 0.0];
+}
+
+function spreadOfLiteral(): array
+{
+	return [...['heading' => 'h', 'start' => 1.0], 'start' => 0.0];
+}
+
+/** @param array{heading: string, start: float} $section */
+function duplicateExplicitKeysAfterSpread(array $section): array
+{
+	return [...$section, 'start' => 0.0, 'start' => 1.0];
+}
+
+function intKeysOfVariable(): array
+{
+	$list = [1, 2];
+	return [...$list, 0 => 'x'];
+}
+
+function numericStringKeyAfterSpreadOfList(): array
+{
+	$list = [1, 2];
+	return [...$list, '0' => 'x'];
+}
+
+/** @param array{'0': string, start: float} $section */
+function numericStringKeyAfterSpread(array $section): array
+{
+	return [...$section, '0' => 'x'];
+}
+
+/** @param array{'0': string, start: float} $section */
+function stringKeyAfterSpreadWithNumericStringKey(array $section): array
+{
+	return [...$section, 'start' => 0.0];
+}
+
+/** @param array{'0': string, start: float} $section */
+function numericStringKeyBeforeSpread(array $section): array
+{
+	return ['0' => 'x', ...$section];
+}
+
+function spreadOfLiteralWithNumericStringKey(): array
+{
+	return [...['0' => 'a'], '0' => 'x'];
+}