fix: gracefully handle version download failure (#1554)

src/renderer/state.ts

@@ -931,17 +931,30 @@ export class AppState {
    * @returns {Promise<void>}
    */
   public async setVersion(input: string): Promise<void> {
-    // make sure we can  use this version
+    const fallback = this.findUsableVersion();
+
     const { err, ver } = this.isVersionUsable(input);
     if (!ver) {
-      console.warn(`setVersion('${input}') failed: ${err}`);
+      console.error(`setVersion('${input}') failed: ${err}`);
       this.showErrorDialog(err!);
-      const fallback = this.findUsableVersion();
       if (fallback) await this.setVersion(fallback.version);
       return;
     }
 
     const { version } = ver;
+
+    try {
+      await this.downloadVersion(ver);
+    } catch {
+      await this.removeVersion(ver);
+      console.error(
+        `setVersion('${input}') failed: Couldn't download ${version}`,
+      );
+      this.showErrorDialog(`Failed to download Electron version ${version}`);
+      if (fallback) await this.setVersion(fallback.version);
+      return;
+    }
+
     console.log(`State: Switching to Electron ${version}`);
     this.version = version;
 
@@ -959,9 +972,6 @@ export class AppState {
         await window.app.replaceFiddle(values, options);
       }
     }
-
-    // Fetch new binaries, maybe?
-    await this.downloadVersion(ver);
   }
 
   /**

tests/renderer/state-spec.ts

@@ -406,6 +406,23 @@ describe('AppState', () => {
       expect(appState.downloadVersion).toHaveBeenCalled();
     });
 
+    it('falls back if downloading the new version fails', async () => {
+      appState.downloadVersion = jest
+        .fn()
+        .mockRejectedValueOnce(new Error('FAILURE'));
+      appState.showGenericDialog = jest.fn().mockResolvedValueOnce({
+        confirm: true,
+      });
+
+      await appState.setVersion('v2.0.2');
+      expect(appState.showGenericDialog).toHaveBeenCalledWith({
+        label: 'Failed to download Electron version 2.0.2',
+        ok: 'Close',
+        type: GenericDialogType.warning,
+        wantsInput: false,
+      });
+    });
+
     describe('loads the template for the new version', () => {
       let newVersion: string;
       let oldVersion: string;