invariant checking

Author: guybedford

lib/loader.js

@@ -51,6 +51,67 @@ function logloads(loads) {
   return log;
 } */
 
+
+function checkInvariants() {
+  // see https://bugs.ecmascript.org/show_bug.cgi?id=2603#c1
+
+  var loads = System._loader.loads;
+  var linkSets = [];
+  
+  for (var i = 0; i < loads.length; i++) {
+    var load = loads[i];
+    console.assert(load.status == 'loading' || load.status == 'loaded', 'Each load is loading or loaded');
+
+    for (var j = 0; j < load.linkSets.length; j++) {
+      var linkSet = load.linkSets[j];
+
+      for (var k = 0; k < linkSet.loads.length; k++)
+        console.assert(loads.indexOf(linkSet.loads[k]) != -1, 'linkSet loads are a subset of loader loads');
+
+      if (linkSets.indexOf(linkSet) == -1)
+        linkSets.push(linkSet);
+    }
+  }
+
+  for (var i = 0; i < loads.length; i++) {
+    var load = loads[i];
+    for (var j = 0; j < linkSets.length; j++) {
+      var linkSet = linkSets[j];
+
+      if (linkSet.loads.indexOf(load) != -1)
+        console.assert(load.linkSets.indexOf(linkSet) != -1, 'linkSet contains load -> load contains linkSet');
+
+      if (load.linkSets.indexOf(linkSet) != -1)
+        console.assert(linkSet.loads.indexOf(load) != -1, 'load contains linkSet -> linkSet contains load');
+    }
+  }
+
+  for (var i = 0; i < linkSets.length; i++) {
+    var linkSet = linkSets[i];
+    for (var j = 0; j < linkSet.loads.length; j++) {
+      var load = linkSet.loads[j];
+
+      for (var k = 0; k < load.dependencies.length; k++) {
+        var depName = load.dependencies[k].value;
+        var depLoad;
+        for (var l = 0; l < loads.length; l++) {
+          if (loads[l].name != depName)
+            continue;
+          depLoad = loads[l];
+          break;
+        }
+
+        // loading records are allowed not to have their dependencies yet
+        // if (load.status != 'loading')
+        //  console.assert(depLoad, 'depLoad found');
+
+        // console.assert(linkSet.loads.indexOf(depLoad) != -1, 'linkset contains all dependencies');
+      }
+    }
+  }
+}
+
+
 (function (__global) {
   (function() {
     var Promise = __global.Promise || require('es6-promise').Promise;
@@ -126,12 +187,14 @@ function logloads(loads) {
 
     // 15.2.4.2
     function requestLoad(loader, request, refererName, refererAddress) {
+      checkInvariants();
       // 15.2.4.2.1 CallNormalize
       return new Promise(function(resolve, reject) {
         resolve(loader.loaderObj.normalize(request, refererName, refererAddress));
       })
       // 15.2.4.2.2 GetOrCreateLoad
       .then(function(name) {
+        checkInvariants();
         var load;
         if (loader.modules[name]) {
           load = createLoad(name);
@@ -159,6 +222,7 @@ function logloads(loads) {
 
     // 15.2.4.3
     function proceedToLocate(loader, load) {
+      checkInvariants();
       proceedToFetch(loader, load,
         Promise.resolve()
         // 15.2.4.3.1 CallLocate
@@ -170,6 +234,7 @@ function logloads(loads) {
 
     // 15.2.4.4
     function proceedToFetch(loader, load, p) {
+      checkInvariants();
       proceedToTranslate(loader, load,
         p
         // 15.2.4.4.1 CallFetch
@@ -185,16 +250,19 @@ function logloads(loads) {
 
     // 15.2.4.5
     function proceedToTranslate(loader, load, p) {
+      checkInvariants();
       p
       // 15.2.4.5.1 CallTranslate
       .then(function(source) {
+        checkInvariants();
         if (load.status != 'loading')
           return;
         return loader.loaderObj.translate({ name: load.name, metadata: load.metadata, address: load.address, source: source });
       })
 
       // 15.2.4.5.2 CallInstantiate
       .then(function(source) {
+        checkInvariants();
         if (load.status != 'loading')
           return;
         load.source = source;
@@ -203,6 +271,7 @@ function logloads(loads) {
 
       // 15.2.4.5.3 InstantiateSucceeded
       .then(function(instantiateResult) {
+        checkInvariants();
         if (load.status != 'loading')
           return;
 
@@ -288,14 +357,16 @@ function logloads(loads) {
 
         // 15.2.4.6 ProcessLoadDependencies
         load.dependencies = [];
-        load.depsList = depsList
+        load.depsList = depsList;
         var loadPromises = [];
         for (var i = 0, l = depsList.length; i < l; i++) (function(request) {
+          checkInvariants();
           loadPromises.push(
             requestLoad(loader, request, load.name, load.address)
 
             // 15.2.4.6.1 AddDependencyLoad (load is parentLoad)
             .then(function(depLoad) {
+              checkInvariants();
 
               console.assert(!load.dependencies.some(function(dep) {
                 return dep.key == request;
@@ -323,6 +394,7 @@ function logloads(loads) {
 
       // 15.2.4.6.2 LoadSucceeded
       .then(function() {
+        checkInvariants();
         // console.log('LoadSucceeded ' + load.name);
         // snapshot(loader);
 
@@ -337,6 +409,7 @@ function logloads(loads) {
 
       // 15.2.4.5.4 LoadFailed
       ['catch'](function(exc) {
+        checkInvariants();
         console.assert(load.status == 'loading', 'is loading on fail');
         load.status = 'failed';
         load.exception = exc;
@@ -353,6 +426,7 @@ function logloads(loads) {
 
     // 15.2.4.7.1
     function asyncStartLoadPartwayThrough(stepState) {
+      checkInvariants();
       return function(resolve, reject) {
         var loader = stepState.loader;
         var name = stepState.moduleName;