[AppService]: fix #16838- az cli update app setting command always making slotsetting to true

src/azure-cli/azure/cli/command_modules/appservice/_help.py

@@ -1092,7 +1092,7 @@
   - name: --settings
     short-summary: Space-separated appsettings in KEY=VALUE format. Use @{file} to load from a file.
   - name: --slot-settings
-    short-summary: Space-separated slot appsettings in KEY=VALUE format. Use @{file} to load from a file.
+    short-summary: Space-separated appsettings in KEY=VALUE format. Use @{file} to load from a file. Given setting are added to the configuration and marked as Deployment slot setting by default.
 """
 
 helps['webapp config backup'] = """

src/azure-cli/azure/cli/command_modules/appservice/custom.py

@@ -252,22 +252,23 @@ def update_app_settings(cmd, resource_group_name, name, settings=None, slot=None
                                            'list_application_settings', slot)
     result, slot_result = {}, {}
     # pylint: disable=too-many-nested-blocks
-    for src, dest in [(settings, result), (slot_settings, slot_result)]:
+    for src, dest, setting_type in [(settings, result, "Settings"), (slot_settings, slot_result, "SlotSettings")]:
         for s in src:
             try:
                 temp = shell_safe_json_parse(s)
                 if isinstance(temp, list):  # a bit messy, but we'd like accept the output of the "list" command
                     for t in temp:
-                        if t.get('slotSetting', True):
-                            slot_result[t['name']] = t['value']
-                            # Mark each setting as the slot setting
-                        else:
-                            result[t['name']] = t['value']
+                        if 'slotSetting' in t.keys():
+                            slot_result[t['name']] = t['slotSetting']
+                        if setting_type == "SlotSettings":
+                            slot_result[t['name']] = True
+                        result[t['name']] = t['value']
                 else:
                     dest.update(temp)
             except CLIError:
                 setting_name, value = s.split('=', 1)
                 dest[setting_name] = value
+                result.update(dest)
 
     result.update(slot_result)
     for setting_name, value in result.items():
@@ -280,10 +281,14 @@ def update_app_settings(cmd, resource_group_name, name, settings=None, slot=None
 
     app_settings_slot_cfg_names = []
     if slot_result:
-        new_slot_setting_names = slot_result.keys()
         slot_cfg_names = client.web_apps.list_slot_configuration_names(resource_group_name, name)
         slot_cfg_names.app_setting_names = slot_cfg_names.app_setting_names or []
-        slot_cfg_names.app_setting_names += new_slot_setting_names
+        # Slot settings logic to add a new setting(s) or remove an existing setting(s)
+        for slot_setting_name, value in slot_result.items():
+            if value and slot_setting_name not in slot_cfg_names.app_setting_names:
+                slot_cfg_names.app_setting_names.append(slot_setting_name)
+            elif not value and slot_setting_name in slot_cfg_names.app_setting_names:
+                slot_cfg_names.app_setting_names.remove(slot_setting_name)
         app_settings_slot_cfg_names = slot_cfg_names.app_setting_names
         client.web_apps.update_slot_configuration_names(resource_group_name, name, slot_cfg_names)
 

src/azure-cli/azure/cli/command_modules/appservice/tests/latest/test_webapp_commands.py

@@ -617,17 +617,17 @@ def test_update_webapp_settings_thru_json(self, resource_group):
 
         self.assertEqual(output[0], {
             'name': 's',
-            'value': 'value',
+            'value': 'False',
             'slotSetting': False
         })
         self.assertEqual(output[1], {
             'name': 's2',
-            'value': 'value2',
+            'value': 'False',
             'slotSetting': False
         })
         self.assertEqual(output[2], {
             'name': 's3',
-            'value': 'value3',
+            'value': 'True',
             'slotSetting': True
         })
         # update site config