fix(transaction): avoid unnecessarily updating initial state in betwe…

…en transactions

lib/plugins/trackTransaction.js

@@ -27,13 +27,6 @@ module.exports = function trackTransaction(schema) {
       initialState.atomics = _getAtomics(this);
 
       session[sessionNewDocuments].set(this, initialState);
-    } else {
-      const state = session[sessionNewDocuments].get(this);
-
-      for (const path of Object.keys(this.$__.activePaths.getStatePaths('modify'))) {
-        state.modifiedPaths.add(path);
-      }
-      state.atomics = _getAtomics(this, state.atomics);
     }
   });
 };

test/docs/transactions.test.js

@@ -565,6 +565,62 @@ describe('transactions', function() {
     assert.equal(i, 3);
   });
 
+  it('transaction() avoids duplicating atomic operations (gh-14848)', async function() {
+    db.deleteModel(/Test/);
+    // Define some schemas...
+    const subItemSchema = new mongoose.Schema(
+      { 
+        name: { type: String, required: true },
+      },
+      { _id: false }
+    );
+
+    const itemSchema = new mongoose.Schema(
+      {
+        name: { type: String, required: true },
+        subItems: { type: [subItemSchema], required: true },
+      },
+      { _id: false }
+    );
+
+    const schema = new mongoose.Schema({
+      items: { type: [itemSchema], required: true },
+    });
+
+    // ...and a model
+    const Test = db.model("Test", schema);
+
+
+    await Test.createCollection();
+    await Test.deleteMany({});
+
+    const { _id } = await Test.create({
+      items: [
+        { name: "test1", subItems: [{ name: "x1" }] },
+        { name: "test2", subItems: [{ name: "x2" }] },
+      ],
+    });
+
+    let doc = await Test.findById(_id);
+
+    doc.items.push({ name: "test3", subItems: [{ name: "x3" }] });    
+
+    let i = 0;
+    await db.transaction(async(session) => {
+      await doc.save({ session });
+      if (++i < 3) {
+        throw new mongoose.mongo.MongoServerError({
+          errorLabels: ['TransientTransactionError']
+        });
+      }
+    });
+
+    assert.equal(i, 3);
+
+    doc = await Test.findById(_id);
+    assert.equal(doc.items.length, 3);
+  });
+
   it('doesnt apply schema write concern to transaction operations (gh-11382)', async function() {
     db.deleteModel(/Test/);
     const Test = db.model('Test', Schema({ status: String }, { writeConcern: { w: 'majority' } }));

test/document.test.js

@@ -8177,14 +8177,14 @@ describe('document', function() {
     await person.save();
   });
 
-  it('set() merge option with double nested', async function () {
+  it('set() merge option with double nested', async function() {
     const PersonSchema = new Schema({
       info: {
         address: {
           city: String,
-          country: { type: String, default: "UK" },
+          country: { type: String, default: 'UK' },
           postcode: String
-        },
+        }
       }
     });
 
@@ -8194,19 +8194,19 @@ describe('document', function() {
     const person = new Person({
       info: {
         address: {
-          country: "United States",
-          city: "New York"
-        },
+          country: 'United States',
+          city: 'New York'
+        }
       }
     });
 
-    const update = { info: { address: { postcode: "12H" } } };
+    const update = { info: { address: { postcode: '12H' } } };
 
     person.set(update, undefined, { merge: true });
-  
-    assert.equal(person.info.address.city, "New York");
-    assert.equal(person.info.address.postcode, "12H");
-    assert.equal(person.info.address.country, "United States");
+
+    assert.equal(person.info.address.city, 'New York');
+    assert.equal(person.info.address.postcode, '12H');
+    assert.equal(person.info.address.country, 'United States');
   });
 
   it('setting single nested subdoc with timestamps (gh-8251)', async function() {