Merge pull request #34 from nodejs/jk-delay-run

Delay run until breakpoints are restored

Author: jkrems

examples/alive.js

@@ -1,4 +1,3 @@
-'use strict';
 let x = 0;
 function heartbeat() {
   ++x;

examples/backtrace.js

@@ -1,4 +1,3 @@
-'use strict';
 const { exports: moduleScoped } = module;
 
 function topFn(a, b = false) {

examples/cjs/index.js

@@ -1,5 +1,5 @@
-'use strict';
+const fourty = 40;
 const { add } = require('./other');
 
-const sum = add(40, 2);
+const sum = add(fourty, 2);
 module.exports = sum;

examples/cjs/other.js

@@ -1,4 +1,3 @@
-'use strict';
 exports.add = function add(a, b) {
   return a + b;
 };

examples/exceptions.js

@@ -1,4 +1,3 @@
-'use strict';
 let error = null;
 try {
   throw new Error('Caught');

examples/three-lines.js

@@ -1,4 +1,3 @@
-'use strict';
 let x = 1;
 x = x + 1;
 module.exports = x;

examples/use-strict.js

@@ -0,0 +1,2 @@
+'use strict';
+console.log('first real line');

lib/_inspect.js

@@ -22,6 +22,7 @@
 'use strict';
 const { spawn } = require('child_process');
 const { EventEmitter } = require('events');
+const net = require('net');
 const util = require('util');
 
 const runAsStandalone = typeof __dirname !== 'undefined';
@@ -99,6 +100,45 @@ function createAgentProxy(domain, client) {
   });
 }
 
+function portIsFree(host, port, timeout = 2000) {
+  const retryDelay = 150;
+  let didTimeOut = false;
+
+  return new Promise((resolve, reject) => {
+    setTimeout(() => {
+      didTimeOut = true;
+      reject(new Error(
+        `Timeout (${timeout}) waiting for ${host}:${port} to be free`));
+    }, timeout);
+
+    function pingPort() {
+      if (didTimeOut) return;
+
+      const socket = net.connect(port, host);
+      let didRetry = false;
+      function retry() {
+        if (!didRetry && !didTimeOut) {
+          didRetry = true;
+          setTimeout(pingPort, retryDelay);
+        }
+      }
+
+      socket.on('error', (error) => {
+        if (error.code === 'ECONNREFUSED') {
+          resolve();
+        } else {
+          retry();
+        }
+      });
+      socket.on('connect', () => {
+        socket.destroy();
+        retry();
+      });
+    }
+    pingPort();
+  });
+}
+
 class NodeInspector {
   constructor(options, stdin, stdout) {
     this.options = options;
@@ -139,8 +179,9 @@ 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);
         });
@@ -150,15 +191,19 @@ 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; }));
   }
@@ -173,7 +218,14 @@ class NodeInspector {
 
   run() {
     this.killChild();
-    return this._runScript().then((child) => {
+    const { host, port } = this.options;
+
+    const runOncePortIsFree = () => {
+      return portIsFree(host, port)
+        .then(() => this._runScript());
+    };
+
+    return runOncePortIsFree().then((child) => {
       this.child = child;
 
       let connectionAttempts = 0;
@@ -198,7 +250,6 @@ class NodeInspector {
           });
       };
 
-      const { host, port } = this.options;
       this.print(`connecting to ${host}:${port} ..`, true);
       return attemptConnect();
     });

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(`${results.length} breakpoints restored.`);
     });
   }
@@ -770,16 +770,19 @@ function createRepl(inspector) {
     const breakType = reason === 'other' ? 'break' : reason;
     const script = knownScripts[scriptId];
     const scriptUrl = script ? getRelativePath(script.url) : '[unknown]';
-    print(`${breakType} in ${scriptUrl}:${lineNumber + 1}`);
+
+    const header = `${breakType} in ${scriptUrl}:${lineNumber + 1}`;
 
     inspector.suspendReplWhile(() =>
       Promise.all([formatWatchers(true), selectedFrame.list(2)])
         .then(([watcherList, context]) => {
           if (watcherList) {
             return `${watcherList}\n${inspect(context)}`;
           }
-          return context;
-        }).then(print));
+          return inspect(context);
+        }).then((breakContext) => {
+          print(`${header}\n${breakContext}`);
+        }));
   });
 
   function handleResumed() {
@@ -1026,7 +1029,30 @@ 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 +1061,7 @@ 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 +1071,8 @@ 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;
   };