bug #51880 [AssetMapper] Fix entrypoint scripts are not preloaded (sm…

…nandre)

This PR was squashed before being merged into the 6.4 branch.

Discussion
----------

[AssetMapper] Fix entrypoint scripts are not preloaded

| Q             | A
| ------------- | ---
| Branch?       | 6.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| License       | MIT

Preload the "rendered" importmap entryoints (ex: "app.js")
(expected behaviour)

Simple test with "`app.js`" entrypoint and two imported scripts "`foo.js`" and ... "`Crocodile.js`".

**Before** (priority: normal / order: last)

![before](https://github.com/symfony/symfony/assets/1359581/cabde9da-e790-44f5-9ea6-317d994ef57b)

**After** (expected behaviour: highest priority)

![after](https://github.com/symfony/symfony/assets/1359581/88a781a1-015a-42bb-9eb6-df581112c21e)

(screenshots made with Firefox on macOS)

Commits
-------

769b896 [AssetMapper] Fix entrypoint scripts are not preloaded

src/Symfony/Component/AssetMapper/ImportMap/ImportMapManager.php

@@ -87,23 +87,22 @@ public function getImportMapData(array $entrypointNames): array
     {
         $rawImportMapData = $this->getRawImportMapData();
         $finalImportMapData = [];
-        foreach ($entrypointNames as $entry) {
-            $finalImportMapData[$entry] = $rawImportMapData[$entry];
-            foreach ($this->findEagerEntrypointImports($entry) as $dependency) {
-                if (isset($finalImportMapData[$dependency])) {
+        foreach ($entrypointNames as $entrypointName) {
+            $entrypointImports = $this->findEagerEntrypointImports($entrypointName);
+            // Entrypoint modules must be preloaded before their dependencies
+            foreach ([$entrypointName, ...$entrypointImports] as $import) {
+                if (isset($finalImportMapData[$import])) {
                     continue;
                 }
 
-                if (!isset($rawImportMapData[$dependency])) {
-                    // missing dependency - rely on browser or compilers to warn
+                // Missing dependency - rely on browser or compilers to warn
+                if (!isset($rawImportMapData[$import])) {
                     continue;
                 }
 
-                // re-order the final array by order of dependencies
-                $finalImportMapData[$dependency] = $rawImportMapData[$dependency];
-                // and mark for preloading
-                $finalImportMapData[$dependency]['preload'] = true;
-                unset($rawImportMapData[$dependency]);
+                $finalImportMapData[$import] = $rawImportMapData[$import];
+                $finalImportMapData[$import]['preload'] = true;
+                unset($rawImportMapData[$import]);
             }
         }
 

src/Symfony/Component/AssetMapper/Tests/ImportMap/ImportMapManagerTest.php

@@ -457,6 +457,11 @@ public function testGetImportMapData()
                 path: 'entry2.js',
                 isEntrypoint: true,
             ),
+            new ImportMapEntry(
+                'entry3',
+                path: 'entry3.js',
+                isEntrypoint: true,
+            ),
             new ImportMapEntry(
                 'normal_js_file',
                 path: 'normal_js_file.js',
@@ -483,6 +488,11 @@ public function testGetImportMapData()
             publicPathWithoutDigest: '/assets/imported_file2.js',
             publicPath: '/assets/imported_file2-d1g35t.js',
         );
+        $importedFile3 = new MappedAsset(
+            'imported_file3.js',
+            publicPathWithoutDigest: '/assets/imported_file3.js',
+            publicPath: '/assets/imported_file3-d1g35t.js',
+        );
         $normalJsFile = new MappedAsset(
             'normal_js_file.js',
             publicPathWithoutDigest: '/assets/normal_js_file.js',
@@ -527,8 +537,16 @@ public function testGetImportMapData()
                     new JavaScriptImport('/assets/styles/file2.css', isLazy: false, asset: $importedCss2, addImplicitlyToImportMap: true),
                 ]
             ),
+            new MappedAsset(
+                'entry3.js',
+                publicPath: '/assets/entry3-d1g35t.js',
+                javaScriptImports: [
+                    new JavaScriptImport('/assets/imported_file3.js', isLazy: false, asset: $importedFile3),
+                ],
+            ),
             $importedFile1,
             $importedFile2,
+            // $importedFile3,
             $normalJsFile,
             $importedCss1,
             $importedCss2,
@@ -542,6 +560,7 @@ public function testGetImportMapData()
             'entry1' => [
                 'path' => '/assets/entry1-d1g35t.js',
                 'type' => 'js',
+                'preload' => true, // Rendered entry points are preloaded
             ],
             '/assets/imported_file1.js' => [
                 'path' => '/assets/imported_file1-d1g35t.js',
@@ -551,6 +570,7 @@ public function testGetImportMapData()
             'entry2' => [
                 'path' => '/assets/entry2-d1g35t.js',
                 'type' => 'js',
+                'preload' => true,  // Rendered entry points are preloaded
             ],
             '/assets/imported_file2.js' => [
                 'path' => '/assets/imported_file2-d1g35t.js',
@@ -577,6 +597,10 @@ public function testGetImportMapData()
                 'type' => 'css',
                 'preload' => true,
             ],
+            'entry3' => [
+                'path' => '/assets/entry3-d1g35t.js',
+                'type' => 'js', // No preload (entry point not "rendered")
+            ],
             'never_imported_css' => [
                 'path' => '/assets/styles/never_imported_css-d1g35t.css',
                 'type' => 'css',
@@ -598,6 +622,7 @@ public function testGetImportMapData()
             'normal_js_file',
 
             // importmap entries never imported
+            'entry3',
             'never_imported_css',
         ], array_keys($actualImportMapData));
     }