Fix theme name requirement regression with efficient lookup by name (#35007)

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

app/helpers/theme_helper.rb

@@ -4,13 +4,11 @@ module ThemeHelper
   def theme_style_tags(theme)
     if theme == 'system'
       ''.html_safe.tap do |tags|
-        tags << vite_stylesheet_tag('styles/mastodon-light.scss', media: 'not all and (prefers-color-scheme: dark)', crossorigin: 'anonymous')
-        tags << vite_stylesheet_tag('styles/application.scss', media: '(prefers-color-scheme: dark)', crossorigin: 'anonymous')
+        tags << vite_stylesheet_tag('themes/mastodon-light', type: :virtual, media: 'not all and (prefers-color-scheme: dark)', crossorigin: 'anonymous')
+        tags << vite_stylesheet_tag('themes/default', type: :virtual, media: '(prefers-color-scheme: dark)', crossorigin: 'anonymous')
       end
-    elsif theme == 'default'
-      vite_stylesheet_tag 'styles/application.scss', media: 'all', crossorigin: 'anonymous'
     else
-      vite_stylesheet_tag "styles/#{theme}.scss", media: 'all', crossorigin: 'anonymous'
+      vite_stylesheet_tag "themes/#{theme}", type: :virtual, media: 'all', crossorigin: 'anonymous'
     end
   end
 

config/vite/plugin-mastodon-themes.ts

@@ -29,7 +29,7 @@ export function MastodonThemes(): Plugin {
         throw new Error('Invalid themes.yml file');
       }
 
-      for (const themePath of Object.values(themes)) {
+      for (const [themeName, themePath] of Object.entries(themes)) {
         if (
           typeof themePath !== 'string' ||
           themePath.split('.').length !== 2 || // Ensure it has exactly one period
@@ -40,7 +40,7 @@ export function MastodonThemes(): Plugin {
           );
           continue;
         }
-        entrypoints[path.basename(themePath)] = path.resolve(
+        entrypoints[`themes/${themeName}`] = path.resolve(
           userConfig.root,
           themePath,
         );

config/vite/plugin-name-lookup.ts

@@ -0,0 +1,68 @@
+import { relative, extname } from 'node:path';
+
+import type { Plugin } from 'vite';
+
+export function MastodonNameLookup(): Plugin {
+  const nameMap: Record<string, string> = {};
+
+  let root = '';
+
+  return {
+    name: 'mastodon-name-lookup',
+    applyToEnvironment(environment) {
+      return !!environment.config.build.manifest;
+    },
+    configResolved(userConfig) {
+      root = userConfig.root;
+    },
+    generateBundle(options, bundle) {
+      if (!root) {
+        throw new Error(
+          'MastodonNameLookup plugin requires the root to be set in the config.',
+        );
+      }
+
+      // Iterate over all chunks in the bundle and create a lookup map
+      for (const file in bundle) {
+        const chunk = bundle[file];
+        if (
+          chunk?.type !== 'chunk' ||
+          !chunk.isEntry ||
+          !chunk.facadeModuleId
+        ) {
+          continue;
+        }
+
+        const relativePath = relative(
+          root,
+          sanitizeFileName(chunk.facadeModuleId),
+        );
+        const ext = extname(relativePath);
+        const name = chunk.name.replace(ext, '');
+
+        if (nameMap[name]) {
+          throw new Error(
+            `Entrypoint ${relativePath} conflicts with ${nameMap[name]}`,
+          );
+        }
+
+        nameMap[name] = relativePath;
+      }
+
+      this.emitFile({
+        type: 'asset',
+        fileName: '.vite/manifest-lookup.json',
+        source: JSON.stringify(nameMap, null, 2),
+      });
+    },
+  };
+}
+
+// Taken from https://github.com/rollup/rollup/blob/4f69d33af3b2ec9320c43c9e6c65ea23a02bdde3/src/utils/sanitizeFileName.ts
+// https://datatracker.ietf.org/doc/html/rfc2396
+// eslint-disable-next-line no-control-regex
+const INVALID_CHAR_REGEX = /[\u0000-\u001F"#$%&*+,:;<=>?[\]^`{|}\u007F]/g;
+
+function sanitizeFileName(name: string): string {
+  return name.replace(INVALID_CHAR_REGEX, '');
+}

lib/vite_ruby/sri_extensions.rb

@@ -7,6 +7,24 @@ module ViteRuby::ManifestIntegrityExtension
     { path: entry.fetch('file'), integrity: entry.fetch('integrity', nil) }
   end
 
+  def load_manifest
+    # Invalidate the name lookup cache when reloading manifest
+    @name_lookup_cache = load_name_lookup_cache
+
+    super
+  end
+
+  def load_name_lookup_cache
+    Oj.load(config.build_output_dir.join('.vite/manifest-lookup.json').read)
+  end
+
+  # Upstream's `virtual` type is a hack, re-implement it with efficient exact name lookup
+  def resolve_virtual_entry(name)
+    @name_lookup_cache ||= load_name_lookup_cache
+
+    @name_lookup_cache.fetch(name)
+  end
+
   # Find a manifest entry by the *final* file name
   def integrity_hash_for_file(file_name)
     @integrity_cache ||= {}
@@ -94,10 +112,10 @@ module ViteRails::TagHelpers::IntegrityExtension
     end
   end
 
-  def vite_stylesheet_tag(*names, **options)
+  def vite_stylesheet_tag(*names, type: :stylesheet, **options)
     ''.html_safe.tap do |tags|
       names.each do |name|
-        entry = vite_manifest.path_and_integrity_for(name, type: :stylesheet)
+        entry = vite_manifest.path_and_integrity_for(name, type:)
 
         options[:extname] = false if Rails::VERSION::MAJOR >= 7
 

spec/helpers/theme_helper_spec.rb

@@ -17,7 +17,7 @@ RSpec.describe ThemeHelper do
           )
         expect(html_links.last.attributes.symbolize_keys)
           .to include(
-            href: have_attributes(value: match(/application/)),
+            href: have_attributes(value: match(/default/)),
             media: have_attributes(value: '(prefers-color-scheme: dark)')
           )
       end
@@ -26,10 +26,10 @@ RSpec.describe ThemeHelper do
     context 'when using "default" theme' do
       let(:theme) { 'default' }
 
-      it 'returns the application stylesheet' do
+      it 'returns the default stylesheet' do
         expect(html_links.last.attributes.symbolize_keys)
           .to include(
-            href: have_attributes(value: match(/application/))
+            href: have_attributes(value: match(/default/))
           )
       end
     end

vite.config.mts

@@ -16,6 +16,7 @@ import postcssPresetEnv from 'postcss-preset-env';
 import { MastodonServiceWorkerLocales } from './config/vite/plugin-sw-locales';
 import { MastodonEmojiCompressed } from './config/vite/plugin-emoji-compressed';
 import { MastodonThemes } from './config/vite/plugin-mastodon-themes';
+import { MastodonNameLookup } from './config/vite/plugin-name-lookup';
 
 const jsRoot = path.resolve(__dirname, 'app/javascript');
 
@@ -125,6 +126,7 @@ export const config: UserConfigFnPromise = async ({ mode, command }) => {
       // Old library types need to be converted
       optimizeLodashImports() as PluginOption,
       !!process.env.ANALYZE_BUNDLE_SIZE && (visualizer() as PluginOption),
+      MastodonNameLookup(),
     ],
   } satisfies UserConfig;
 };