Display error for native properties/getters

Matt Loring · Matt Loring · commit c0f3350d7fab · 2016-01-19T12:29:35.000-08:00
This prevents native properties/getters from being reported as undefined
when we are unable to check their values for fear of executing stateful
code.
diff --git a/lib/state.js b/lib/state.js
@@ -26,6 +26,10 @@ var semver = require('semver');
 
 var StatusMessage = require('./apiclasses.js').StatusMessage;
 
+var BUFFER_FULL_MESSAGE_INDEX = 0;
+var NATIVE_PROPERTY_MESSAGE_INDEX = 1;
+var GETTER_MESSAGE_INDEX = 2;
+
 // TODO: document this file
 
 // returns an object with three fields: stacksframes,
@@ -79,13 +83,17 @@ function StateResolver(execState, expressions, config) {
   this.evaluatedExpressions_ = [];
   this.totalSize_ = 0;
 
-  // The 0-th object in the variable table is a sentinel 'buffer full' error
-  // message value
-  this.rawVariableTable_ = [ null ];
-  this.resolvedVariableTable_ = [
+  this.rawVariableTable_ = [ null, null, null ];
+  this.resolvedVariableTable_ = [];
+  this.resolvedVariableTable_[BUFFER_FULL_MESSAGE_INDEX] =
+    { status: new StatusMessage(StatusMessage.VARIABLE_VALUE,
+                                'Max data size reached', true) };
+  this.resolvedVariableTable_[NATIVE_PROPERTY_MESSAGE_INDEX] =
+    { status: new StatusMessage(StatusMessage.VARIABLE_VALUE,
+                                'Native properties are not available', true) };
+  this.resolvedVariableTable_[GETTER_MESSAGE_INDEX] =
     { status: new StatusMessage(StatusMessage.VARIABLE_VALUE,
-                                'Buffer full', true) }
-  ];
+                                'Properties with getters are not available', true) };
 }
 
 
@@ -114,7 +122,7 @@ StateResolver.prototype.capture = function() {
   }
 
   // Now resolve the variables
-  var index = 1; // skip the sentinel value
+  var index = 3; // skip the sentinel values
   while (index < that.rawVariableTable_.length && // NOTE: length changes in loop
          that.totalSize_ < that.config_.capture.maxDataSize) {
     assert(!that.resolvedVariableTable_[index]); // shouldn't have it resolved yet
@@ -145,7 +153,7 @@ StateResolver.prototype.trimVariableTable_ = function(fromIndex, frames) {
     variables.forEach(function (variable) {
       if (variable.varTableIndex && variable.varTableIndex >= fromIndex) {
         // make it point to the sentinel 'buffer full' value
-        variable.varTableIndex = 0;
+        variable.varTableIndex = BUFFER_FULL_MESSAGE_INDEX;
       }
       if (variable.members) {
         processBufferFull(variable.members);
@@ -365,7 +373,7 @@ StateResolver.prototype.resolveMirrorSlow_ = function(mirror) {
     keys = keys.slice(0, that.config_.capture.maxProperties);
   }
   var members = keys.map(function(prop) {
-    return that.resolveVariable_(prop, mirror.property(prop).value());
+    return that.resolveMirrorProperty_(mirror.property(prop));
   });
 
   return {
@@ -386,11 +394,23 @@ StateResolver.prototype.resolveMirrorFast_ = function(mirror) {
   };
 };
 StateResolver.prototype.getMirrorProperties_ = function(mirror) {
-  var numProperties = this.config_.capture.maxProperties || 1000;
+  var numProperties = this.config_.capture.maxProperties;
   var namedProperties = mirror.properties(1, numProperties);
   var indexedProperties = mirror.properties(2, numProperties);
   return namedProperties.concat(indexedProperties);
 };
 StateResolver.prototype.resolveMirrorProperty_ = function(property) {
+  if (property.isNative()) {
+    return {
+      name: property.name(),
+      varTableIndex: NATIVE_PROPERTY_MESSAGE_INDEX
+    };
+  }
+  if (property.hasGetter()) {
+    return {
+      name: property.name(),
+      varTableIndex: GETTER_MESSAGE_INDEX
+    };
+  }
   return this.resolveVariable_(property.name(), property.value());
 };
diff --git a/test/test-v8debugapi.js b/test/test-v8debugapi.js
@@ -3,6 +3,10 @@
 /*3*/function foo(n) {
 /*4*/  return n+42;
 /*5*/}
+/*6*/function getterObject() {
+/*7*/  var hasGetter = { _a: 5, get a() { return this._a; } };
+/*8*/  return hasGetter.a;
+/*9*/}
 /**
  * Copyright 2015 Google Inc. All Rights Reserved.
  *
@@ -332,7 +336,40 @@ describe('v8debugapi', function() {
         });
         process.nextTick(function() {foo(3);});
       });
+    });
+
+    it('should report error for native prop or getter', function(done) {
+      var bp = {
+        id: 'fake-id-124',
+        location: { path: 'test-v8debugapi.js', line: 8 },
+        expressions: ['process.env', 'hasGetter']
+      };
+      api.set(bp, function(err) {
+        assert.ifError(err);
+        api.wait(bp, function(err) {
+          assert.ifError(err);
+
+          var procEnv = bp.evaluatedExpressions[0];
+          assert.equal(procEnv.name, 'process.env');
+          var envVal = bp.variableTable[procEnv.varTableIndex];
+          envVal.members.forEach(function(member) {
+            assert(bp.variableTable[member.varTableIndex].status.isError);
+          });
+          var hasGetter = bp.evaluatedExpressions[1];
+          var getterVal = bp.variableTable[hasGetter.varTableIndex];
+          assert(getterVal.members.some(function(m) {
+            return m.value === '5';
+          }));
+          assert(getterVal.members.some(function(m) {
+            var resolved = bp.variableTable[m.varTableIndex];
+            return resolved && resolved.status.isError;
+          }));
 
+          api.clear(bp);
+          done();
+        });
+        process.nextTick(function() {getterObject();});
+      });
     });
 
     it('should capture without values for invalid watch expressions', function(done) {
