if phone number is already filled in on user, do not overwrite

src/djangooidc/backends.py

@@ -65,13 +65,35 @@ class OpenIdConnectBackend(ModelBackend):
         return user
 
     def update_existing_user(self, user, kwargs):
-        """Update other fields without overwriting first_name and last_name.
-        Overwrite first_name and last_name if not empty string"""
+        """
+        Update user fields without overwriting certain fields.
 
+        Args:
+            user: User object to be updated.
+            kwargs: Dictionary containing fields to update and their new values.
+
+        Note:
+            This method updates user fields while preserving the values of 'first_name',
+            'last_name', and 'phone' fields, unless specific conditions are met.
+
+            - 'phone' field will be updated if it's None or an empty string.
+            - 'first_name' and 'last_name' will be updated if the provided value is not empty.
+        """
+
+        # Iterate over fields to update
         for key, value in kwargs.items():
-            # Check if the key is not first_name or last_name or value is not empty string
-            if key not in ["first_name", "last_name"] or value:
+            # Check if the field is not 'first_name', 'last_name', or 'phone',
+            # or if it's the 'phone' field and 'user.phone' is None or empty,
+            # or if it's 'first_name' or 'last_name' and the provided value is not empty
+            if (
+                key not in ["first_name", "last_name", "phone"]
+                or (key == "phone" and (user.phone is None or user.phone == ""))
+                or (key in ["first_name", "last_name"] and value)
+            ):
+                # Update the corresponding attribute of the user object
                 setattr(user, key, value)
+
+        # Save the user object with the updated fields
         user.save()
 
     def clean_username(self, username):

src/djangooidc/tests/test_backends.py

@@ -50,11 +50,16 @@ class OpenIdConnectBackendTestCase(TestCase):
         self.assertEqual(user.email, "john.doe@example.com")
         self.assertEqual(user.phone, "123456789")
 
-    def test_authenticate_with_existing_user_no_name(self):
+    def test_authenticate_with_existing_user_with_existing_first_last_phone(self):
         """Test that authenticate updates an existing user if it finds one.
-        For this test, given_name and family_name are not supplied"""
+        For this test, given_name and family_name are not supplied.
+
+        The existing user's first and last name are not overwritten.
+        The existing user's phone number is not overwritten"""
         # Create an existing user with the same username and with first and last names
-        existing_user = User.objects.create_user(username="test_user", first_name="John", last_name="Doe")
+        existing_user = User.objects.create_user(
+            username="test_user", first_name="WillNotBe", last_name="Replaced", phone="9999999999"
+        )
 
         # Remove given_name and family_name from the input, self.kwargs
         self.kwargs.pop("given_name", None)
@@ -67,6 +72,48 @@ class OpenIdConnectBackendTestCase(TestCase):
         self.assertIsInstance(user, User)
         self.assertEqual(user, existing_user)  # The same user instance should be returned
 
+        # Verify that user fields are correctly updated
+        self.assertEqual(user.first_name, "WillNotBe")
+        self.assertEqual(user.last_name, "Replaced")
+        self.assertEqual(user.email, "john.doe@example.com")
+        self.assertEqual(user.phone, "9999999999")
+
+    def test_authenticate_with_existing_user_with_no_phone_will_update_phone(self):
+        """Test that authenticate updates an existing user if it finds one.
+        For this test, the existing user has an empty string for phone
+
+        The existing user's phone number is overwritten"""
+        # Create an existing user with the same username and with first and last names
+        existing_user = User.objects.create_user(username="test_user", phone="")
+
+        # Ensure that the authenticate method updates the existing user
+        # and preserves existing first and last names
+        user = self.backend.authenticate(request=None, **self.kwargs)
+        self.assertIsNotNone(user)
+        self.assertIsInstance(user, User)
+        self.assertEqual(user, existing_user)  # The same user instance should be returned
+
+        # Verify that user fields are correctly updated
+        self.assertEqual(user.first_name, "John")
+        self.assertEqual(user.last_name, "Doe")
+        self.assertEqual(user.email, "john.doe@example.com")
+        self.assertEqual(user.phone, "123456789")
+
+    def test_authenticate_with_existing_user_with_none_phone_will_update_phone(self):
+        """Test that authenticate updates an existing user if it finds one.
+        For this test, the existing user has None for phone
+
+        The existing user's phone number is overwritten"""
+        # Create an existing user with the same username and with first and last names
+        existing_user = User.objects.create_user(username="test_user")
+
+        # Ensure that the authenticate method updates the existing user
+        # and preserves existing first and last names
+        user = self.backend.authenticate(request=None, **self.kwargs)
+        self.assertIsNotNone(user)
+        self.assertIsInstance(user, User)
+        self.assertEqual(user, existing_user)  # The same user instance should be returned
+
         # Verify that user fields are correctly updated
         self.assertEqual(user.first_name, "John")
         self.assertEqual(user.last_name, "Doe")