Mark array_filter(), array_map(), array_reduce() and PHP 8.4 array_find/array_any/array_all as pure in function metadata

bin/functionMetadata_original.php

@@ -20,6 +20,8 @@
 	'apcu_key_info' => ['hasSideEffects' => true],
 	'apcu_sma_info' => ['hasSideEffects' => true],
 	'apcu_store' => ['hasSideEffects' => true],
+	'array_all' => ['hasSideEffects' => false],
+	'array_any' => ['hasSideEffects' => false],
 	'array_change_key_case' => ['hasSideEffects' => false],
 	'array_chunk' => ['hasSideEffects' => false],
 	'array_column' => ['hasSideEffects' => false],
@@ -32,6 +34,9 @@
 	'array_diff_ukey' => ['hasSideEffects' => false],
 	'array_fill' => ['hasSideEffects' => false],
 	'array_fill_keys' => ['hasSideEffects' => false],
+	'array_filter' => ['hasSideEffects' => false],
+	'array_find' => ['hasSideEffects' => false],
+	'array_find_key' => ['hasSideEffects' => false],
 	'array_flip' => ['hasSideEffects' => false],
 	'array_intersect' => ['hasSideEffects' => false],
 	'array_intersect_assoc' => ['hasSideEffects' => false],
@@ -42,13 +47,15 @@
 	'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

@@ -725,6 +725,8 @@
 	'apcu_key_info' => ['hasSideEffects' => true],
 	'apcu_sma_info' => ['hasSideEffects' => true],
 	'apcu_store' => ['hasSideEffects' => true],
+	'array_all' => ['hasSideEffects' => false],
+	'array_any' => ['hasSideEffects' => false],
 	'array_change_key_case' => ['hasSideEffects' => false],
 	'array_chunk' => ['hasSideEffects' => false],
 	'array_column' => ['hasSideEffects' => false],
@@ -737,6 +739,9 @@
 	'array_diff_ukey' => ['hasSideEffects' => false],
 	'array_fill' => ['hasSideEffects' => false],
 	'array_fill_keys' => ['hasSideEffects' => false],
+	'array_filter' => ['hasSideEffects' => false],
+	'array_find' => ['hasSideEffects' => false],
+	'array_find_key' => ['hasSideEffects' => false],
 	'array_first' => ['hasSideEffects' => false],
 	'array_flip' => ['hasSideEffects' => false],
 	'array_intersect' => ['hasSideEffects' => false],
@@ -750,13 +755,15 @@
 	'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/Analyser/nsrt/array-find-key.php

@@ -1,26 +1,4 @@
-<?php
-
-namespace {
-
-	if (!function_exists('array_find_key')) {
-		/**
-		 * @param array<mixed> $array
-		 * @param callable(mixed, array-key=): mixed $callback
-		 * @return ?array-key
-		 */
-		function array_find_key(array $array, callable $callback)
-		{
-			foreach ($array as $key => $value) {
-				if ($callback($value, $key)) { // @phpstan-ignore if.condNotBoolean
-					return $key;
-				}
-			}
-
-			return null;
-		}
-	}
-
-}
+<?php // lint >= 8.4
 
 namespace ArrayFindKey
 {

tests/PHPStan/Analyser/nsrt/array-find.php

@@ -1,26 +1,4 @@
-<?php
-
-namespace {
-
-	if (!function_exists('array_find')) {
-		/**
-		 * @param array<mixed> $array
-		 * @param callable(mixed, array-key=): mixed $callback
-		 * @return mixed
-		 */
-		function array_find(array $array, callable $callback)
-		{
-			foreach ($array as $key => $value) {
-				if ($callback($value, $key)) { // @phpstan-ignore if.condNotBoolean
-					return $value;
-				}
-			}
-
-			return null;
-		}
-	}
-
-}
+<?php // lint >= 8.4
 
 namespace ArrayFind
 {

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 +119,69 @@ 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.',
+				13,
+			],
+			[
+				'Call to function array_map() on a separate line has no effect.',
+				14,
+			],
+			[
+				'Call to function array_reduce() on a separate line has no effect.',
+				15,
+			],
+		]);
+	}
+
+	#[RequiresPhp('>= 8.4.0')]
+	public function testBug11101Php84(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-11101-php84.php'], [
+			[
+				'Call to function array_find() on a separate line has no effect.',
+				13,
+			],
+			[
+				'Call to function array_find_key() on a separate line has no effect.',
+				14,
+			],
+			[
+				'Call to function array_any() on a separate line has no effect.',
+				15,
+			],
+			[
+				'Call to function array_all() on a separate line has no effect.',
+				16,
+			],
+		]);
+	}
+
+	public function testBug11101CustomPure(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-11101-custom-pure.php'], [
+			[
+				'Call to function Bug11101CustomPure\pureWithImmediateCallback() on a separate line has no effect.',
+				38,
+			],
+			[
+				'Call to function Bug11101CustomPure\pureWithLaterCallback() on a separate line has no effect.',
+				56,
+			],
+			[
+				'Call to function Bug11101CustomPure\pureWithLaterCallback() on a separate line has no effect.',
+				59,
+			],
+			[
+				'Call to function Bug11101CustomPure\pureWithLaterCallback() on a separate line has no effect.',
+				65,
+			],
+		]);
+	}
+
 	#[RequiresPhp('>= 8.5.0')]
 	public function testPipeOperator(): void
 	{

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

@@ -0,0 +1,68 @@
+<?php
+
+namespace Bug11101CustomPure;
+
+/**
+ * @phpstan-pure
+ * @param array<int> $array
+ * @param callable(int): bool $callback
+ * @param-immediately-invoked-callable $callback
+ * @return array<int>
+ */
+function pureWithImmediateCallback(array $array, callable $callback): array
+{
+	return array_filter($array, $callback);
+}
+
+/**
+ * @phpstan-pure
+ * @param array<int> $array
+ * @param callable(int): bool $callback
+ * @param-later-invoked-callable $callback
+ * @return array<int>
+ */
+function pureWithLaterCallback(array $array, callable $callback): array
+{
+	return $array;
+}
+
+class Foo
+{
+
+	/**
+	 * @param array<int> $array
+	 */
+	public function testImmediateCallback(array $array, callable $callback): void
+	{
+		// Pure callback - should be reported
+		pureWithImmediateCallback($array, fn ($v) => $v > 5);
+
+		// Impure callback - should NOT be reported
+		pureWithImmediateCallback($array, function ($v) {
+			echo $v;
+			return $v > 0;
+		});
+
+		// Unknown callback - should NOT be reported
+		pureWithImmediateCallback($array, $callback);
+	}
+
+	/**
+	 * @param array<int> $array
+	 */
+	public function testLaterCallback(array $array, callable $callback): void
+	{
+		// Pure callback - should be reported
+		pureWithLaterCallback($array, fn ($v) => $v > 5);
+
+		// Impure callback - should be reported (later-invoked, callback impurity doesn't matter at call site)
+		pureWithLaterCallback($array, function ($v) {
+			echo $v;
+			return $v > 0;
+		});
+
+		// Unknown callback - should be reported (later-invoked, callback impurity doesn't matter at call site)
+		pureWithLaterCallback($array, $callback);
+	}
+
+}

tests/PHPStan/Rules/Functions/data/bug-11101-php84.php

@@ -0,0 +1,19 @@
+<?php // lint >= 8.4
+
+namespace Bug11101Php84;
+
+class Foo
+{
+
+	/**
+	 * @param array<int> $array
+	 */
+	public function doFoo(array $array): void
+	{
+		array_find($array, fn ($v) => $v > 5);
+		array_find_key($array, fn ($v) => $v > 5);
+		array_any($array, fn ($v) => $v > 5);
+		array_all($array, fn ($v) => $v > 5);
+	}
+
+}

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

@@ -0,0 +1,37 @@
+<?php
+
+namespace Bug11101;
+
+class Foo
+{
+
+	/**
+	 * @param array<int> $array
+	 */
+	public function doFoo(array $array): void
+	{
+		array_filter($array, 'is_string');
+		array_map('is_string', $array);
+		array_reduce($array, function ($carry, $item) {
+			return $carry + $item;
+		}, 0);
+	}
+
+	/**
+	 * @param array<int> $array
+	 */
+	public function doBar(array $array, callable $callback): void
+	{
+		// These should NOT be reported because the callback might be impure
+		array_filter($array, $callback);
+		array_map($callback, $array);
+		array_reduce($array, $callback, 0);
+
+		// Impure closure should not be reported
+		array_filter($array, function ($v) {
+			echo $v;
+			return $v > 0;
+		});
+	}
+
+}