NODE-899 Make upsertedId value from updateOne compatible with pre 2.2.12

Author: christkv

lib/collection.js

@@ -896,6 +896,12 @@ var updateOne = function(self, filter, update, options, callback) {
     r.upsertedId = Array.isArray(r.result.upserted) && r.result.upserted.length > 0 ? r.result.upserted[0]._id : null;
     r.upsertedCount = Array.isArray(r.result.upserted) && r.result.upserted.length ? r.result.upserted.length : 0;
     r.matchedCount = Array.isArray(r.result.upserted) && r.result.upserted.length > 0 ? 0 : r.result.n;
+
+    // Fix for NODE-899, backward compatibility with legacy format
+    if(r.upsertedId) {
+      r.upsertedId._id = r.upsertedId;
+    }
+
     if(callback) callback(null, r);
   });
 }

test/functional/crud_api_tests.js

@@ -536,6 +536,8 @@ exports['should correctly execute update methods using crud api'] = {
             test.equal(1, r.result.n);
             test.equal(0, r.matchedCount);
             test.ok(r.upsertedId != null);
+            test.equal('ObjectID', r.upsertedId._bsontype);
+            test.equal('ObjectID', r.upsertedId._id._bsontype);
 
             db.collection('t3_2').updateOne({ c: 1 }
               , { $set: { a: 1 } }, function(err, r) {