fix: Delay run until breakpoints are restored

Author: Jan Krems

lib/_inspect.js

@@ -130,8 +130,9 @@ class NodeInspector {
     process.once('SIGHUP', process.exit.bind(process, 0));
 
     this.run()
-      .then(() => {
-        this.repl = startRepl();
+      .then(() => startRepl())
+      .then((repl) => {
+        this.repl = repl;
         this.repl.on('exit', () => {
           process.exit(0);
         });
@@ -141,15 +142,19 @@ class NodeInspector {
   }
 
   suspendReplWhile(fn) {
-    this.repl.rli.pause();
+    if (this.repl) {
+      this.repl.rli.pause();
+    }
     this.stdin.pause();
     this.paused = true;
     return new Promise((resolve) => {
       resolve(fn());
     }).then(() => {
       this.paused = false;
-      this.repl.rli.resume();
-      this.repl.displayPrompt();
+      if (this.repl) {
+        this.repl.rli.resume();
+        this.repl.displayPrompt();
+      }
       this.stdin.resume();
     }).then(null, (error) => process.nextTick(() => { throw error; }));
   }

lib/internal/inspect_client.js

@@ -334,20 +334,7 @@ class Client extends EventEmitter {
         this.emit('close');
       });
 
-      Promise.all([
-        this.callMethod('Runtime.enable'),
-        this.callMethod('Debugger.enable'),
-        this.callMethod('Debugger.setPauseOnExceptions', { state: 'none' }),
-        this.callMethod('Debugger.setAsyncCallStackDepth', { maxDepth: 0 }),
-        this.callMethod('Profiler.enable'),
-        this.callMethod('Profiler.setSamplingInterval', { interval: 100 }),
-        this.callMethod('Debugger.setBlackboxPatterns', { patterns: [] }),
-        this.callMethod('Runtime.runIfWaitingForDebugger'),
-      ]).then(() => {
-        this.emit('ready');
-      }, (error) => {
-        this.emit('error', error);
-      });
+      this.emit('ready');
     };
 
     return new Promise((resolve, reject) => {

lib/internal/inspect_repl.js

@@ -748,8 +748,8 @@ function createRepl(inspector) {
       .filter(({ location }) => !!location.scriptUrl)
       .map(({ location }) =>
         setBreakpoint(location.scriptUrl, location.lineNumber + 1));
-    if (!newBreakpoints.length) return;
-    Promise.all(newBreakpoints).then((results) => {
+    if (!newBreakpoints.length) return Promise.resolve();
+    return Promise.all(newBreakpoints).then((results) => {
       print(`${results.length} breakpoints restored.`);
     });
   }
@@ -1026,7 +1026,30 @@ function createRepl(inspector) {
     aliasProperties(context, SHORTCUTS);
   }
 
+  function initAfterStart() {
+    const setupTasks = [
+      Runtime.enable(),
+      Profiler.enable(),
+      Profiler.setSamplingInterval({ interval: 100 }),
+      Debugger.enable(),
+      Debugger.setPauseOnExceptions({ state: 'none' }),
+      Debugger.setAsyncCallStackDepth({ maxDepth: 0 }),
+      Debugger.setBlackboxPatterns({ patterns: [] }),
+      Debugger.setPauseOnExceptions({ state: pauseOnExceptionState }),
+      restoreBreakpoints(),
+      Runtime.runIfWaitingForDebugger(),
+    ];
+    return Promise.all(setupTasks);
+  }
+
   return function startRepl() {
+    inspector.client.on('close', () => {
+      resetOnStart();
+    });
+    inspector.client.on('ready', () => {
+      initAfterStart();
+    });
+
     const replOptions = {
       prompt: 'debug> ',
       input: inspector.stdin,
@@ -1035,6 +1058,7 @@ function createRepl(inspector) {
       useGlobal: false,
       ignoreUndefined: true,
     };
+
     repl = Repl.start(replOptions); // eslint-disable-line prefer-const
     initializeContext(repl.context);
     repl.on('reset', initializeContext);
@@ -1044,14 +1068,8 @@ function createRepl(inspector) {
       repl.rli.emit('SIGINT');
     });
 
-    inspector.client.on('close', () => {
-      resetOnStart();
-    });
-
-    inspector.client.on('ready', () => {
-      restoreBreakpoints();
-      Debugger.setPauseOnExceptions({ state: pauseOnExceptionState });
-    });
+    // Init once for the initial connection
+    initAfterStart();
 
     return repl;
   };

test/cli/launch.test.js

@@ -8,7 +8,9 @@ const startCLI = require('./start-cli');
 test('examples/empty.js', (t) => {
   const script = Path.join('examples', 'empty.js');
   const cli = startCLI([script]);
-  return cli.waitForPrompt()
+
+  return cli.waitFor(/break/)
+    .then(() => cli.waitForPrompt())
     .then(() => {
       t.match(cli.output, 'debug>', 'prints a prompt');
       t.match(