Enhancement: Implement UnwrapArrayReduce mutator

src/Mutator/Unwrap/AbstractUnwrapMutator.php

@@ -63,6 +63,10 @@ final protected function mutatesNode(Node $node): bool
             return false;
         }
 
+        if (!array_key_exists($this->getParameterIndex(), $node->args)) {
+            return false;
+        }
+
         return $node->name->toLowerString() === strtolower($this->getFunctionName());
     }
 }

src/Mutator/Unwrap/UnwrapArrayReduce.php

@@ -0,0 +1,52 @@
+<?php
+/**
+ * This code is licensed under the BSD 3-Clause License.
+ *
+ * Copyright (c) 2017-2018, Maks Rafalko
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright notice, this
+ *   list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright notice,
+ *   this list of conditions and the following disclaimer in the documentation
+ *   and/or other materials provided with the distribution.
+ *
+ * * Neither the name of the copyright holder nor the names of its
+ *   contributors may be used to endorse or promote products derived from
+ *   this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+declare(strict_types=1);
+
+namespace Infection\Mutator\Unwrap;
+
+/**
+ * @internal
+ */
+final class UnwrapArrayReduce extends AbstractUnwrapMutator
+{
+    protected function getFunctionName(): string
+    {
+        return 'array_reduce';
+    }
+
+    protected function getParameterIndex(): int
+    {
+        return 2;
+    }
+}

src/Mutator/Util/MutatorProfile.php

@@ -190,6 +190,7 @@ final class MutatorProfile
         Mutator\Unwrap\UnwrapArrayFilter::class,
         Mutator\Unwrap\UnwrapArrayFlip::class,
         Mutator\Unwrap\UnwrapArrayMap::class,
+        Mutator\Unwrap\UnwrapArrayReduce::class,
         Mutator\Unwrap\UnwrapArrayReverse::class,
     ];
 
@@ -317,6 +318,7 @@ final class MutatorProfile
         'UnwrapArrayFilter' => Mutator\Unwrap\UnwrapArrayFilter::class,
         'UnwrapArrayFlip' => Mutator\Unwrap\UnwrapArrayFlip::class,
         'UnwrapArrayMap' => Mutator\Unwrap\UnwrapArrayMap::class,
+        'UnwrapArrayReduce' => Mutator\Unwrap\UnwrapArrayReduce::class,
         'UnwrapArrayReverse' => Mutator\Unwrap\UnwrapArrayReverse::class,
     ];
 }

tests/Mutator/Unwrap/UnwrapArrayReduceTest.php

@@ -0,0 +1,229 @@
+<?php
+/**
+ * This code is licensed under the BSD 3-Clause License.
+ *
+ * Copyright (c) 2017-2018, Maks Rafalko
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright notice, this
+ *   list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright notice,
+ *   this list of conditions and the following disclaimer in the documentation
+ *   and/or other materials provided with the distribution.
+ *
+ * * Neither the name of the copyright holder nor the names of its
+ *   contributors may be used to endorse or promote products derived from
+ *   this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+declare(strict_types=1);
+
+namespace Infection\Tests\Mutator\Unwrap;
+
+use Infection\Tests\Mutator\AbstractMutatorTestCase;
+
+/**
+ * @internal
+ */
+final class UnwrapArrayReduceTest extends AbstractMutatorTestCase
+{
+    /**
+     * @dataProvider provideMutationCases
+     */
+    public function test_mutator($input, $expected = null): void
+    {
+        $this->doTest($input, $expected);
+    }
+
+    public function provideMutationCases(): \Generator
+    {
+        yield 'It mutates correctly when the $initial parameter is provided as an array' => [
+            <<<'PHP'
+<?php
+
+$a = array_reduce(
+    ['A', 1, 'C'],
+    function ($carry, $item) {
+       return $item;
+    }, 
+    ['D']
+);
+PHP
+            ,
+            <<<'PHP'
+<?php
+
+$a = ['D'];
+PHP
+        ];
+
+        yield 'It mutates correctly when the $initial parameter is provided as a constant' => [
+            <<<'PHP'
+<?php
+
+$a = array_reduce(
+    ['A', 1, 'C'],
+    function ($carry, $item) {
+       return $item;
+    }, 
+    \Class_With_Const::Const
+);
+PHP
+            ,
+            <<<'PHP'
+<?php
+
+$a = \Class_With_Const::Const;
+PHP
+        ];
+
+        yield 'It mutates correctly when the $initial parameter is provided and a backslash is in front of array_reduce' => [
+            <<<'PHP'
+<?php
+
+$a = \array_reduce(
+    ['A', 1, 'C'],
+    function ($carry, $item) {
+       return $item;
+    },  
+    ['D']
+);
+PHP
+            ,
+            <<<'PHP'
+<?php
+
+$a = ['D'];
+PHP
+        ];
+
+        yield 'It mutates correctly within if statements when the $initial parameter is provided' => [
+            <<<'PHP'
+<?php
+
+$a = ['A', 1, 'C'];
+if (array_reduce($a, function ($carry, $item) { return $item; }, ['D']) === $a) {
+    return true;
+}
+PHP
+            ,
+            <<<'PHP'
+<?php
+
+$a = ['A', 1, 'C'];
+if (['D'] === $a) {
+    return true;
+}
+PHP
+        ];
+
+        yield 'It mutates correctly when the $initial parameter is provided and array_reduce is wrongly capitalized' => [
+            <<<'PHP'
+<?php
+
+$a = aRrAy_ReDuCe(
+    ['A', 1, 'C'],
+    function ($carry, $item) { 
+        return $item;
+    }, 
+    ['D']
+);
+PHP
+            ,
+            <<<'PHP'
+<?php
+
+$a = ['D'];
+PHP
+        ];
+
+        yield 'It mutates correctly when the $initial parameter is provided and array_reduce uses other functions as input' => [
+            <<<'PHP'
+<?php
+
+$a = array_reduce(
+    $foo->bar(), 
+    $foo->baz(), 
+    $foo->qux()
+);
+PHP
+            ,
+            <<<'PHP'
+<?php
+
+$a = $foo->qux();
+PHP
+        ];
+
+        yield 'It mutates correctly when the $initial parameter is provided in a more complex situation' => [
+            <<<'PHP'
+<?php
+
+$a = array_map('strtolower', array_reduce(['A', 1, 'C'], $callback, ['D']));
+PHP
+            ,
+            <<<'PHP'
+<?php
+
+$a = array_map('strtolower', ['D']);
+PHP
+        ];
+
+        yield 'It mutates correctly when the the $initial parameter is provided and the $callback parameter is provided as a variable' => [
+            <<<'PHP'
+<?php
+
+$a = array_reduce(['A', 1, 'C'], $callback, ['D']);
+PHP
+            ,
+            <<<'PHP'
+<?php
+
+$a = ['D'];
+PHP
+        ];
+
+        yield 'It does not mutate when the $initial parameter is not provided' => [
+            <<<'PHP'
+<?php
+
+$a = array_reduce(['A', 1, 'C'], function ($carry, $item) {
+    return $item;
+});
+PHP
+        ];
+
+        yield 'It does not mutate other array_ calls' => [
+            <<<'PHP'
+<?php
+
+$a = array_map('strtolower', ['A', 'B', 'C']);
+PHP
+        ];
+
+        yield 'It does not mutate functions named array_reduce' => [
+            <<<'PHP'
+<?php
+
+function array_reduce($array, $callback, $initial = null)
+{
+}
+PHP
+        ];
+    }
+}