fix(core): keep track of application restarts and close stdin pipe co…

…rrectly

previously we weren't tracking application restarts in the CLI module or closing our stdin pipe once
the child app had quit

ISSUES CLOSED: #545

packages/api/cli/src/electron-forge-start.ts

@@ -1,5 +1,6 @@
 import { api, StartOptions } from '@electron-forge/core';
 
+import { ChildProcess } from 'child_process';
 import fs from 'fs-extra';
 import path from 'path';
 import program from 'commander';
@@ -64,12 +65,26 @@ import './util/terminate';
   const spawned = await api.start(opts);
 
   await new Promise((resolve) => {
-    spawned.on('exit', (code: number) => {
-      if ((spawned as any).restarted) return;
-      if (code !== 0) {
-        process.exit(code);
-      }
-      resolve();
-    });
+    const listenForExit = (child: ChildProcess) => {
+      const removeListeners = () => {
+        child.removeListener('exit', onExit);
+        child.removeListener('restarted', onRestart);
+      };
+      const onExit = (code: number) => {
+        removeListeners();
+        if ((spawned as any).restarted) return;
+        if (code !== 0) {
+          process.exit(code);
+        }
+        resolve();
+      };
+      const onRestart = (newChild: ChildProcess) => {
+        removeListeners();
+        listenForExit(newChild);
+      };
+      child.on('exit', onExit);
+      child.on('restarted', onRestart);
+    };
+    listenForExit(spawned);
   });
 })();

packages/api/core/src/api/start.ts

@@ -53,6 +53,21 @@ export default async ({
 
   const forgeSpawnWrapper = async () => {
     lastSpawned = await forgeSpawn();
+    // When the child app is closed we should stop listening for stdin
+    if (lastSpawned) {
+      if (interactive && process.stdin.isPaused()) {
+        process.stdin.resume();
+      }
+      lastSpawned.on('exit', () => {
+        if ((lastSpawned as any).restarted) return;
+
+        if (!process.stdin.isPaused()) process.stdin.pause();
+      });
+    } else {
+      if (interactive && !process.stdin.isPaused()) {
+        process.stdin.pause();
+      }
+    }
     return lastSpawned;
   };
 
@@ -114,12 +129,12 @@ export default async ({
   };
 
   if (interactive) {
-    process.stdin.on('data', (data) => {
+    process.stdin.on('data', async (data) => {
       if (data.toString().trim() === 'rs' && lastSpawned) {
         console.info('\nRestarting App\n'.cyan);
         (lastSpawned as any).restarted = true;
         lastSpawned.kill('SIGTERM');
-        forgeSpawnWrapper();
+        lastSpawned.emit('restarted', await forgeSpawnWrapper());
       }
     });
   }

packages/api/core/test/fast/start_spec.ts

@@ -11,7 +11,7 @@ describe('start', () => {
   let packageJSON: any;
   let resolveStub: SinonStub;
   let spawnStub: SinonStub;
-  let shouldOverride: boolean;
+  let shouldOverride: any;
   let processOn: SinonStub;
 
   beforeEach(() => {
@@ -58,7 +58,7 @@ describe('start', () => {
 
   it('should not spawn if a plugin overrides the start command', async () => {
     resolveStub.returnsArg(0);
-    shouldOverride = true;
+    shouldOverride = { on: () => {} };
     await start({
       dir: __dirname,
       interactive: false,
@@ -172,12 +172,13 @@ describe('start', () => {
 
   it('should resolve with a handle to the spawned instance', async () => {
     resolveStub.returnsArg(0);
-    spawnStub.returns('child');
+    const fakeChild = { on: () => {} };
+    spawnStub.returns(fakeChild);
 
     await expect(start({
       dir: __dirname,
       interactive: false,
       enableLogging: true,
-    })).to.eventually.equal('child');
+    })).to.eventually.equal(fakeChild);
   });
 });