From b17db902a14f5c8d9854b00fe8cf57fe5e3e812f Mon Sep 17 00:00:00 2001
From: Luca Pizzini <lpizzini7@gmail.com>
Date: Fri, 3 Feb 2023 09:20:43 +0100
Subject: [PATCH 1/2] fix(document): isModified should not be triggered when
 setting a nested boolean to the same value as previosly

fix #12992
---
 lib/document.js       |  2 +-
 test/document.test.js | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/lib/document.js b/lib/document.js
index ffa48ce906f..f1ad40dfdbf 100644
--- a/lib/document.js
+++ b/lib/document.js
@@ -1621,7 +1621,7 @@ Document.prototype.$__shouldModify = function(pathToMark, path, options, constru
     return false;
   }
 
-  if (!deepEqual(val, priorVal || utils.getValue(path, this))) {
+  if (!deepEqual(val, priorVal != null ? priorVal : utils.getValue(path, this))) {
     return true;
   }
 
diff --git a/test/document.test.js b/test/document.test.js
index 9804b6b8c18..80380ec26a9 100644
--- a/test/document.test.js
+++ b/test/document.test.js
@@ -12075,6 +12075,41 @@ describe('document', function() {
     assert.equal(doc.list.length, 3);
     assert.deepStrictEqual(doc.list.map(el => el.a), [1, 2, 3]);
   });
+
+  it('should not trigger isModified when setting a nested boolean to the same value as previously  (gh-12992)', async function() {
+    const Test = db.model('Test', new Schema({
+      result: new Schema(
+        {
+          score: Number,
+          passed: Boolean
+        },
+        { _id: false }
+      )
+    }));
+    const newTest = await Test.create({
+      result: {
+        score: 40,
+        passed: false
+      }
+    });
+
+    const existingTest = await Test.findById(newTest._id);
+    existingTest.result = {
+      score: 40,
+      passed: false
+    };
+
+    assert.equal(existingTest.isModified(), false);
+    assert.equal(existingTest.modifiedPaths().length, 0);
+
+    existingTest.result = {
+      score: 40,
+      passed: true
+    };
+
+    assert.equal(existingTest.isModified(), true);
+    assert.equal(existingTest.modifiedPaths().length, 1);
+  });
 });
 
 describe('Check if instance function that is supplied in schema option is availabe', function() {

From a69194fe3b009a08221f5d67dc437f40d49e7595 Mon Sep 17 00:00:00 2001
From: Valeri Karpov <val@karpov.io>
Date: Fri, 3 Feb 2023 17:37:28 -0500
Subject: [PATCH 2/2] Update document.js

---
 lib/document.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/document.js b/lib/document.js
index f1ad40dfdbf..cd5c8b0c84e 100644
--- a/lib/document.js
+++ b/lib/document.js
@@ -1621,7 +1621,7 @@ Document.prototype.$__shouldModify = function(pathToMark, path, options, constru
     return false;
   }
 
-  if (!deepEqual(val, priorVal != null ? priorVal : utils.getValue(path, this))) {
+  if (!deepEqual(val, priorVal !== undefined ? priorVal : utils.getValue(path, this))) {
     return true;
   }