如何优雅地比较数据结构差异？使用diff/diff库轻松实现数据同步与版本控制

<code class="bash">composer require diff/diff:~3.0</code>

<pre class="brush:php;toolbar:false;"><?php

require 'vendor/autoload.php';

use Diff\Differ\MapDiffer;
use Diff\Patcher\MapPatcher;
use Diff\DiffOp\DiffOpAdd;
use Diff\DiffOp\DiffOpChange;
use Diff\DiffOp\DiffOpRemove;

$oldConfig = [
    'username' => 'alice',
    'email' => 'alice@example.com',
    'settings' => [
        'theme' => 'dark',
        'notifications' => true,
        'language' => 'en',
    ],
    'roles' => ['user', 'editor'],
];

$newConfig = [
    'username' => 'alice_new', // 改变
    'email' => 'alice.smith@example.com', // 改变
    'settings' => [
        'theme' => 'light', // 改变
        'notifications' => false, // 改变
        'timezone' => 'UTC', // 新增
    ],
    // 'roles' 被移除
    'status' => 'active', // 新增
];

// 1. 计算差异 (Diffing data)
$differ = new MapDiffer(); // MapDiffer 适用于关联数组，并支持递归比较
$diff = $differ->doDiff($oldConfig, $newConfig);

echo "--- 计算出的差异 ---" . PHP_EOL;
foreach ($diff as $key => $op) {
    if ($op instanceof DiffOpAdd) {
        echo "Added '{$key}': " . json_encode($op->getNewValue()) . PHP_EOL;
    } elseif ($op instanceof DiffOpChange) {
        echo "Changed '{$key}': from " . json_encode($op->getOldValue()) . " to " . json_encode($op->getNewValue()) . PHP_EOL;
    } elseif ($op instanceof DiffOpRemove) {
        echo "Removed '{$key}': " . json_encode($op->getOldValue()) . PHP_EOL;
    } elseif ($op instanceof \Diff\DiffOp\Diff) { // 处理嵌套的 Diff
        echo "Nested diff for '{$key}':" . PHP_EOL;
        foreach ($op->getOps() as $nestedKey => $nestedOp) {
            if ($nestedOp instanceof DiffOpAdd) {
                echo "  Added '{$nestedKey}': " . json_encode($nestedOp->getNewValue()) . PHP_EOL;
            } elseif ($nestedOp instanceof DiffOpChange) {
                echo "  Changed '{$nestedKey}': from " . json_encode($nestedOp->getOldValue()) . " to " . json_encode($nestedOp->getNewValue()) . PHP_EOL;
            } elseif ($nestedOp instanceof DiffOpRemove) {
                echo "  Removed '{$nestedKey}': " . json_encode($nestedOp->getOldValue()) . PHP_EOL;
            }
        }
    }
}

// 2. 应用差异 (Applying patches)
$patcher = new MapPatcher();
$patchedConfig = $patcher->patch($oldConfig, $diff);

echo PHP_EOL . "--- 应用补丁后的配置 ---" . PHP_EOL;
echo json_encode($patchedConfig, JSON_PRETTY_PRINT) . PHP_EOL;

// 验证应用补丁后的配置是否与新配置一致
// assert($patchedConfig == $newConfig); // 实际项目中可以进行断言