feat: Automatically convert MV3 web_accessible_resources to MV2 (#423)

src/core/utils/__tests__/manifest.test.ts

@@ -851,6 +851,55 @@ describe('Manifest Utils', () => {
           'content-scripts/one.css',
         ]);
       });
+
+      it('should convert mv3 items to mv2 strings automatically', async () => {
+        setFakeWxt({
+          config: {
+            outDir,
+            manifestVersion: 2,
+            manifest: {
+              web_accessible_resources: [
+                {
+                  matches: ['*://*/*'],
+                  resources: ['/icon-128.png'],
+                },
+                {
+                  matches: ['https://google.com'],
+                  resources: ['/icon-128.png', '/icon-32.png'],
+                },
+              ],
+            },
+          },
+        });
+
+        const { manifest: actual } = await generateManifest(
+          [],
+          fakeBuildOutput(),
+        );
+
+        expect(actual.web_accessible_resources).toEqual([
+          '/icon-128.png',
+          '/icon-32.png',
+        ]);
+      });
+
+      it('should convert mv2 strings to mv3 items with a warning automatically', async () => {
+        setFakeWxt({
+          config: {
+            outDir,
+            manifestVersion: 3,
+            manifest: {
+              web_accessible_resources: ['/icon.svg'],
+            },
+          },
+        });
+
+        await expect(() =>
+          generateManifest([], fakeBuildOutput()),
+        ).rejects.toThrow(
+          'Non-MV3 web_accessible_resources detected: ["/icon.svg"]. When manually defining web_accessible_resources, define them as MV3 objects ({ matches: [...], resources: [...] }), and WXT will automatically convert them to MV2 when necessary.',
+        );
+      });
     });
 
     describe('transformManifest option', () => {

src/core/utils/manifest.ts

@@ -77,7 +77,7 @@ export async function generateManifest(
   };
   const userManifest = wxt.config.manifest;
 
-  const manifest = defu(
+  let manifest = defu(
     userManifest,
     baseManifest,
   ) as Manifest.WebExtensionManifest;
@@ -116,6 +116,13 @@ export async function generateManifest(
   wxt.config.transformManifest(manifest);
   await wxt.hooks.callHook('build:manifestGenerated', wxt, manifest);
 
+  if (wxt.config.manifestVersion === 2)
+    convertWebAccessibleResourcesToMv2(manifest);
+
+  if (wxt.config.manifestVersion === 3) {
+    validateMv3WebAccessbileResources(manifest);
+  }
+
   if (manifest.name == null)
     throw Error(
       "Manifest 'name' is missing. Either:\n1. Set the name in your <rootDir>/package.json\n2. Set a name via the manifest option in your wxt.config.ts",
@@ -501,7 +508,8 @@ export function getContentScriptCssWebAccessibleResources(
   contentScripts: ContentScriptEntrypoint[],
   contentScriptCssMap: Record<string, string | undefined>,
 ): any[] {
-  const resources: any[] = [];
+  const resources: Manifest.WebExtensionManifestWebAccessibleResourcesC2ItemType[] =
+    [];
 
   contentScripts.forEach((script) => {
     if (script.options.cssInjectionMode !== 'ui') return;
@@ -509,17 +517,13 @@ export function getContentScriptCssWebAccessibleResources(
     const cssFile = contentScriptCssMap[script.name];
     if (cssFile == null) return;
 
-    if (wxt.config.manifestVersion === 2) {
-      resources.push(cssFile);
-    } else {
-      resources.push({
-        resources: [cssFile],
-        matches: resolvePerBrowserOption(
-          script.options.matches,
-          wxt.config.browser,
-        ).map((matchPattern) => stripPathFromMatchPattern(matchPattern)),
-      });
-    }
+    resources.push({
+      resources: [cssFile],
+      matches: resolvePerBrowserOption(
+        script.options.matches,
+        wxt.config.browser,
+      ).map((matchPattern) => stripPathFromMatchPattern(matchPattern)),
+    });
   });
 
   return resources;
@@ -573,3 +577,43 @@ export function stripPathFromMatchPattern(pattern: string) {
   const startOfPath = pattern.indexOf('/', protocolSepIndex + 3);
   return pattern.substring(0, startOfPath) + '/*';
 }
+
+/**
+ * Converts all MV3 web accessible resources to their MV2 forms. MV3 web accessible resources are
+ * generated in this file, and may be defined by the user in their manifest. In both cases, when
+ * targetting MV2, automatically convert their definitions down to the basic MV2 array.
+ */
+export function convertWebAccessibleResourcesToMv2(
+  manifest: Manifest.WebExtensionManifest,
+): void {
+  if (manifest.web_accessible_resources == null) return;
+
+  manifest.web_accessible_resources = Array.from(
+    new Set(
+      manifest.web_accessible_resources.flatMap((item) => {
+        if (typeof item === 'string') return item;
+        return item.resources;
+      }),
+    ),
+  );
+}
+
+/**
+ * Make sure all resources are in MV3 format. If not, add a wanring
+ */
+export function validateMv3WebAccessbileResources(
+  manifest: Manifest.WebExtensionManifest,
+): void {
+  if (manifest.web_accessible_resources == null) return;
+
+  const stringResources = manifest.web_accessible_resources.filter(
+    (item) => typeof item === 'string',
+  );
+  if (stringResources.length > 0) {
+    throw Error(
+      `Non-MV3 web_accessible_resources detected: ${JSON.stringify(
+        stringResources,
+      )}. When manually defining web_accessible_resources, define them as MV3 objects ({ matches: [...], resources: [...] }), and WXT will automatically convert them to MV2 when necessary.`,
+    );
+  }
+}