Mark array_filter, array_map, and array_reduce as pure functions

- Added array_filter, array_map, and array_reduce to bin/functionMetadata_original.php with hasSideEffects => false
- Regenerated resources/functionMetadata.php to include the new entries
- Callback impure points are already tracked separately via processArgs, so impure callbacks will still be detected
- Updated tests/PHPStan/Command/data/file-without-errors.php to assign array_filter result (now correctly flagged as no-effect)
- New regression test in tests/PHPStan/Rules/Functions/data/bug-11101.php

Author: phpstan-bot

bin/functionMetadata_original.php

@@ -18,6 +18,7 @@
 	'array_diff_ukey' => ['hasSideEffects' => false],
 	'array_fill' => ['hasSideEffects' => false],
 	'array_fill_keys' => ['hasSideEffects' => false],
+	'array_filter' => ['hasSideEffects' => false],
 	'array_flip' => ['hasSideEffects' => false],
 	'array_intersect' => ['hasSideEffects' => false],
 	'array_intersect_assoc' => ['hasSideEffects' => false],
@@ -28,13 +29,15 @@
 	'array_key_last' => ['hasSideEffects' => false],
 	'array_key_exists' => ['hasSideEffects' => false],
 	'array_keys' => ['hasSideEffects' => false],
+	'array_map' => ['hasSideEffects' => false],
 	'array_merge' => ['hasSideEffects' => false],
 	'array_merge_recursive' => ['hasSideEffects' => false],
 	'array_pad' => ['hasSideEffects' => false],
 	'array_pop' => ['hasSideEffects' => true],
 	'array_product' => ['hasSideEffects' => false],
 	'array_push' => ['hasSideEffects' => true],
 	'array_rand' => ['hasSideEffects' => false],
+	'array_reduce' => ['hasSideEffects' => false],
 	'array_replace' => ['hasSideEffects' => false],
 	'array_replace_recursive' => ['hasSideEffects' => false],
 	'array_reverse' => ['hasSideEffects' => false],

resources/functionMetadata.php

@@ -724,6 +724,7 @@
 	'array_diff_ukey' => ['hasSideEffects' => false],
 	'array_fill' => ['hasSideEffects' => false],
 	'array_fill_keys' => ['hasSideEffects' => false],
+	'array_filter' => ['hasSideEffects' => false],
 	'array_first' => ['hasSideEffects' => false],
 	'array_flip' => ['hasSideEffects' => false],
 	'array_intersect' => ['hasSideEffects' => false],
@@ -737,13 +738,15 @@
 	'array_key_last' => ['hasSideEffects' => false],
 	'array_keys' => ['hasSideEffects' => false],
 	'array_last' => ['hasSideEffects' => false],
+	'array_map' => ['hasSideEffects' => false],
 	'array_merge' => ['hasSideEffects' => false],
 	'array_merge_recursive' => ['hasSideEffects' => false],
 	'array_pad' => ['hasSideEffects' => false],
 	'array_pop' => ['hasSideEffects' => true],
 	'array_product' => ['hasSideEffects' => false],
 	'array_push' => ['hasSideEffects' => true],
 	'array_rand' => ['hasSideEffects' => false],
+	'array_reduce' => ['hasSideEffects' => false],
 	'array_replace' => ['hasSideEffects' => false],
 	'array_replace_recursive' => ['hasSideEffects' => false],
 	'array_reverse' => ['hasSideEffects' => false],

tests/PHPStan/Command/data/file-without-errors.php

@@ -1,3 +1,3 @@
 <?php
 
-array_filter([0, 1, 2]);
+$a = array_filter([0, 1, 2]);

tests/PHPStan/Rules/Functions/CallToFunctionStatementWithoutSideEffectsRuleTest.php

@@ -119,6 +119,24 @@ public function testFirstClassCallables(): void
 		]);
 	}
 
+	public function testBug11101(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-11101.php'], [
+			[
+				'Call to function array_filter() on a separate line has no effect.',
+				11,
+			],
+			[
+				'Call to function array_map() on a separate line has no effect.',
+				12,
+			],
+			[
+				'Call to function array_reduce() on a separate line has no effect.',
+				13,
+			],
+		]);
+	}
+
 	#[RequiresPhp('>= 8.5')]
 	public function testPipeOperator(): void
 	{

tests/PHPStan/Rules/Functions/data/bug-11101.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace Bug11101;
+
+/**
+ * @param array<mixed> $array
+ */
+function doFoo(array $array): void
+{
+	// These should all be reported as having no effect
+	array_filter($array, 'is_string'); // line 11
+	array_map('is_string', $array); // line 12
+	array_reduce($array, function ($carry, $item) { // line 13
+		return $carry + $item;
+	}, 0);
+
+	// These are fine - using the return value
+	$a = array_filter($array, 'is_string');
+	$b = array_map('is_string', $array);
+	$c = array_reduce($array, function ($carry, $item) {
+		return $carry + $item;
+	}, 0);
+}