AC-10573: Static deploy doesn't update files

Fix static content deployment to check file modification times

- Add modification time checking in Publisher to update files when source is newer
- Add null checks in CSS/LESS preprocessors and CSS URLs post-processor
- Prevents "Call to a member function getPackage() on null" error

Author: sumesh-GL

app/code/Magento/Deploy/Package/Processor/PostProcessor/CssUrls.php

@@ -1,7 +1,7 @@
 <?php
 /**
- * Copyright © Magento, Inc. All rights reserved.
- * See COPYING.txt for license details.
+ * Copyright 2017 Adobe
+ * All rights reserved.
  */
 namespace Magento\Deploy\Package\Processor\PostProcessor;
 
@@ -66,7 +66,7 @@ public function process(Package $package, array $options)
             return false;
         }
         $urlMap = [];
-        /** @var PackageFile $file */
+        /** @var string $fileId */
         foreach (array_keys($package->getMap()) as $fileId) {
             $filePath = str_replace(\Magento\Framework\View\Asset\Repository::FILE_ID_SEPARATOR, '/', $fileId);
             // phpcs:ignore Magento2.Functions.DiscouragedFunction
@@ -227,7 +227,9 @@ private function getValidExternalUrl($url, Package $package)
         if (!$this->isFileExistsInPackage($filePath, $package)) {
             /** @var PackageFile $matchedFile */
             $matchedFile = $this->getFileFromParent($filePath, $package);
-            $package = $matchedFile->getPackage();
+            if ($matchedFile && $matchedFile->getPackage()) {
+                $package = $matchedFile->getPackage();
+            }
         }
         return preg_replace(
             '/(?<=}})(.*)(?=\/{{)/',

lib/internal/Magento/Framework/App/View/Asset/Publisher.php

@@ -1,7 +1,7 @@
 <?php
 /**
- * Copyright © Magento, Inc. All rights reserved.
- * See COPYING.txt for license details.
+ * Copyright 2011 Adobe
+ * All rights reserved.
  */
 
 namespace Magento\Framework\App\View\Asset;
@@ -49,19 +49,60 @@ public function __construct(
     }
 
     /**
+     * Publish the asset
+     *
      * @param Asset\LocalInterface $asset
      * @return bool
      */
     public function publish(Asset\LocalInterface $asset)
     {
         $dir = $this->filesystem->getDirectoryRead(DirectoryList::STATIC_VIEW);
-        if ($dir->isExist($asset->getPath())) {
+        $targetPath = $asset->getPath();
+
+        // Check if target file exists and is newer than source file
+        if ($dir->isExist($targetPath) && !$this->isSourceFileNewer($asset, $dir, $targetPath)) {
             return true;
         }
 
         return $this->publishAsset($asset);
     }
 
+    /**
+     * Check if source file is newer than target file
+     *
+     * @param Asset\LocalInterface $asset
+     * @param \Magento\Framework\Filesystem\Directory\ReadInterface $dir
+     * @param string $targetPath
+     * @return bool
+     */
+    private function isSourceFileNewer(Asset\LocalInterface $asset, $dir, $targetPath)
+    {
+        $sourceFile = $asset->getSourceFile();
+
+        // Check if source file exists
+        if (!file_exists($sourceFile)) {
+            return false;
+        }
+
+        $sourceMtime = $this->getFileModificationTime($sourceFile);
+        $targetStat = $dir->stat($targetPath);
+        $targetMtime = $targetStat['mtime'] ?? 0;
+
+        return $sourceMtime > $targetMtime;
+    }
+
+    /**
+     * Get file modification time
+     *
+     * @param string $filePath
+     * @return int
+     */
+    private function getFileModificationTime($filePath)
+    {
+        $mtime = @filemtime($filePath);
+        return $mtime !== false ? $mtime : 0;
+    }
+
     /**
      * Publish the asset
      *