fix: catch error when ethereum provider is set before our attempt to set (#416)

* catch error when ethereum provider is set before our attempt to set

* update jest.config

Author: adonesky1

jest.config.js

@@ -47,8 +47,8 @@ const baseConfig = {
     global: {
       branches: 70.68,
       functions: 72.32,
-      lines: 71.27,
-      statements: 71.39,
+      lines: 71.39,
+      statements: 71.51,
     },
   },
 

src/initializeInpageProvider.test.ts

@@ -20,6 +20,27 @@ describe('setGlobalProvider', () => {
       new Event('ethereum#initialized'),
     );
   });
+
+  it('should not throw an error if the global ethereum provider is already set', () => {
+    const errorSpy = jest.spyOn(console, 'error');
+
+    const mockProvider = {} as unknown as MetaMaskInpageProvider;
+    Object.defineProperty(window, 'ethereum', {
+      get() {
+        return {};
+      },
+      set() {
+        throw new Error('window.ethereum already set');
+      },
+      configurable: false,
+    });
+    expect(() => setGlobalProvider(mockProvider)).not.toThrow();
+
+    expect(errorSpy).toHaveBeenCalledWith(
+      'MetaMask encountered an error setting the global Ethereum provider - this is likely due to another Ethereum wallet extension also setting the global Ethereum provider:',
+      expect.any(Error),
+    );
+  });
 });
 
 describe('announceCaip294WalletData', () => {

src/initializeInpageProvider.ts

@@ -98,8 +98,15 @@ export function initializeProvider({
 export function setGlobalProvider(
   providerInstance: MetaMaskInpageProvider,
 ): void {
-  (window as Record<string, any>).ethereum = providerInstance;
-  window.dispatchEvent(new Event('ethereum#initialized'));
+  try {
+    (window as Record<string, any>).ethereum = providerInstance;
+    window.dispatchEvent(new Event('ethereum#initialized'));
+  } catch (error) {
+    console.error(
+      'MetaMask encountered an error setting the global Ethereum provider - this is likely due to another Ethereum wallet extension also setting the global Ethereum provider:',
+      error,
+    );
+  }
 }
 
 /**