fix issue #1834

lib/document.js

@@ -1013,6 +1013,8 @@ Document.prototype.invalidate = function (path, err, val) {
     err = new ValidatorError(path, err, 'user defined', val)
   }
 
+  if (this.$__.validationError == err) return;
+
   this.$__.validationError.errors[path] = err;
 }
 

test/errors.validation.test.js

@@ -14,26 +14,58 @@ var assert = require('assert')
   , ValidationError = mongoose.Document.ValidationError
 
 describe('ValidationError', function(){
+  describe('#infiniteRecursion', function(){
+    it('does not cause RangeError (gh-1834)', function(done){
+      var SubSchema
+        , M
+        , model;
+
+      SubSchema = new Schema({
+        name: {type: String, required: true},
+        contents: [new Schema({
+          key:   {type: String, required: true},
+          value: {type: String, required: true}
+        }, {_id: false})]
+      });
+
+      M = mongoose.model('SubSchema', SubSchema);
+
+      model = new M({
+        name: 'Model',
+        contents: [
+          { key: 'foo' }
+        ]
+      });
+
+      model.validate(function(err){
+        assert.doesNotThrow(function(){
+          JSON.stringify(err);
+        });
+        done();
+      });
+    })
+  });
+
   describe('#toString', function(){
     it('does not cause RangeError (gh-1296)', function(done){
       var ASchema = new Schema({
           key: {type: String, required: true}
         , value: {type:String, required: true}
-      })
+      });
 
       var BSchema = new Schema({
           contents: [ASchema]
-      })
+      });
 
       var M = mongoose.model('A', BSchema);
       var m = new M;
       m.contents.push({ key: 'asdf' });
       m.validate(function (err) {
         assert.doesNotThrow(function(){
           String(err)
-        })
+        });
         done();
       });
     })
   })
-})
+});