From 2a09a58085f811b199658ee3036d434f6fb9be8e Mon Sep 17 00:00:00 2001
From: Abdelrahman Awad <logaretm1@Gmail.com>
Date: Wed, 27 Dec 2023 14:14:28 +0100
Subject: [PATCH] fix: check if the target is pojo before attempted merge
 (#4615)

---
 .changeset/fluffy-icons-eat.md              |  5 ++++
 packages/shared/utils.ts                    |  2 +-
 packages/vee-validate/tests/useForm.spec.ts | 27 +++++++++++++++++++++
 3 files changed, 33 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/fluffy-icons-eat.md

diff --git a/.changeset/fluffy-icons-eat.md b/.changeset/fluffy-icons-eat.md
new file mode 100644
index 000000000..42c479b99
--- /dev/null
+++ b/.changeset/fluffy-icons-eat.md
@@ -0,0 +1,5 @@
+---
+"vee-validate": patch
+---
+
+"fix: check if both source and target objects are POJOs"
diff --git a/packages/shared/utils.ts b/packages/shared/utils.ts
index ed0319510..191060e6b 100644
--- a/packages/shared/utils.ts
+++ b/packages/shared/utils.ts
@@ -51,7 +51,7 @@ export function isPlainObject(value: any) {
 
 export function merge(target: any, source: any) {
   Object.keys(source).forEach(key => {
-    if (isPlainObject(source[key])) {
+    if (isPlainObject(source[key]) && isPlainObject(target[key])) {
       if (!target[key]) {
         target[key] = {};
       }
diff --git a/packages/vee-validate/tests/useForm.spec.ts b/packages/vee-validate/tests/useForm.spec.ts
index 9e95a0ce8..e99cfdf7a 100644
--- a/packages/vee-validate/tests/useForm.spec.ts
+++ b/packages/vee-validate/tests/useForm.spec.ts
@@ -1398,4 +1398,31 @@ describe('useForm()', () => {
     await flushPromises();
     await expect(form.errors.value.fname).toBe(undefined);
   });
+
+  test('checks if both source and target are POJO before setting properties', async () => {
+    let form!: FormContext<{ file: { name: string; size: number } }>;
+    const f1 = new File([''], 'f1.text');
+    const f2 = { name: 'f2.text', size: 123 };
+
+    mountWithHoc({
+      setup() {
+        form = useForm({
+          initialValues: { file: f1 },
+        });
+
+        form.defineField('file');
+
+        return {};
+      },
+      template: `
+        <div></div>
+      `,
+    });
+
+    await flushPromises();
+    expect(form.values.file).toBeInstanceOf(File);
+    expect(form.values.file).toBe(f1);
+    form.setValues({ file: f2 });
+    expect(form.values.file).toEqual(f2);
+  });
 });