fix: Fix unused permission detection for endowments with multiple handlers (#3452)

This fixes an edge case in the unused permission detection, for
endowments that can have multiple handlers. For example,
`endowment:lifecycle-hooks` enables two (optional) handlers, `onInstall`
and `onUpdate`. Previously the endowment would be detected as unused,
even if one of the two was exported.

After this change, either can be specified, and the endowment will be
considered used.

Author: Mrtenz

packages/snaps-utils/coverage.json

@@ -2,5 +2,5 @@
   "branches": 99.76,
   "functions": 99,
   "lines": 98.68,
-  "statements": 97.27
+  "statements": 97.28
 }

packages/snaps-utils/src/manifest/validators/unused-exports.test.ts

@@ -91,4 +91,36 @@ describe('unusedExports', () => {
       ),
     );
   });
+
+  it('does not report if the Snap exports a handler and requests permission for it in the manifest', async () => {
+    const report = jest.fn();
+    assert(unusedExports.semanticCheck);
+
+    const files = getMockSnapFiles({
+      manifest: getSnapManifest({
+        initialPermissions: {
+          'endowment:page-home': {},
+          'endowment:rpc': {},
+          'endowment:lifecycle-hooks': {},
+        },
+      }),
+      manifestPath: __filename,
+    });
+
+    await unusedExports.semanticCheck(files, {
+      report,
+      options: {
+        exports: ['onRpcRequest', 'onHomePage', 'onInstall'],
+        handlerEndowments: {
+          onRpcRequest: 'endowment:rpc',
+          onHomePage: 'endowment:page-home',
+          onInstall: 'endowment:lifecycle-hooks',
+          onUpdate: 'endowment:lifecycle-hooks',
+          onUserInput: null,
+        },
+      },
+    });
+
+    expect(report).toHaveBeenCalledTimes(0);
+  });
 });

packages/snaps-utils/src/manifest/validators/unused-exports.ts

@@ -17,6 +17,16 @@ export const unusedExports: ValidatorMeta = {
       return;
     }
 
+    // Endowments used based on the exports from the Snap. This is used to
+    // filter endowments that are used by multiple handlers, e.g., the lifecycle
+    // handlers.
+    const usedEndowments = Object.entries(handlerEndowments)
+      .filter(
+        ([handler, endowment]) =>
+          endowment === null || exports.includes(handler),
+      )
+      .map(([, endowment]) => endowment);
+
     const unusedHandlers = Object.entries(handlerEndowments)
       .filter(([handler, endowment]) => {
         if (endowment === null) {
@@ -39,9 +49,11 @@ export const unusedExports: ValidatorMeta = {
         }
 
         return (
+          !usedEndowments.includes(endowment) &&
           files.manifest.result.initialPermissions[
             endowment as keyof InitialPermissions
-          ] && !exports.includes(handler)
+          ] &&
+          !exports.includes(handler)
         );
       },
     );