fix(web): partial JSON saves to /config/main change only what they send

A JSON body with one field reset every checkbox in the sections it touched:
the MQTT bridge's brightness slider turned off disable_hardware_pulsing,
inverse_colors, show_refresh_rate and use_short_date_format, and a
timezone-only save turned off web-UI autostart and weekly auto-updates.
Missing-means-unchecked now applies only to form posts: form-encoded bodies
and the v3 forms, which mark themselves with a hidden __form_section input.

Also on the config routes:
- vegas_min/max_cycle_duration no longer match the generic *_duration rule,
  so they stop landing in display_durations and a blank one no longer
  rejects the whole Display save;
- saving from the Raw JSON editor calls start_setup_if_needed like the
  General form, so enabling auto-update there finishes its setup;
- the schedule and dim-schedule POSTs accept the per-day days.<day> shape
  their GETs return, as well as the flat form keys.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

test/test_api_v3_partial_main_save.py

@@ -0,0 +1,277 @@
+"""POST /config/main: a partial JSON body changes only what it sends.
+
+The settings forms post every field, and a browser leaves an unchecked box out,
+so for a form a missing checkbox means False. JSON API clients send only what
+they change. Treating their missing keys as unchecked meant:
+
+- the MQTT bridge's Home Assistant brightness slider (``{"brightness": N}``)
+  turned off disable_hardware_pulsing, inverse_colors, show_refresh_rate and
+  use_short_date_format on every change;
+- the documented timezone/location update turned off web_display_autostart and
+  weekly automatic updates.
+
+The v3 forms post JSON as well (htmx json-enc), so they mark themselves with a
+hidden ``__form_section`` input; these tests pin both halves of that contract.
+
+Also here: the Vegas cycle-time fields no longer land in display_durations
+(and a blank one no longer 400s the Display save), the Raw JSON editor starts
+auto-update setup like the General form does, and both schedule POSTs accept
+the per-day shape their GETs return.
+"""
+
+import copy
+import json
+import re
+from pathlib import Path
+
+import pytest
+
+from test._api_v3_test_helpers import api_v3_client, api_v3_module  # noqa: F401
+
+REPO = Path(__file__).resolve().parent.parent
+PARTIALS = REPO / 'web_interface' / 'templates' / 'v3' / 'partials'
+
+STORED = {
+    'web_display_autostart': True,
+    'auto_update': {'enabled': True},
+    'timezone': 'America/Chicago',
+    'plugin_system': {'auto_discover': True, 'auto_load_enabled': True,
+                      'development_mode': True},
+    'display': {
+        'hardware': {'rows': 32, 'cols': 64, 'chain_length': 2, 'brightness': 90,
+                     'disable_hardware_pulsing': True, 'inverse_colors': True,
+                     'show_refresh_rate': True},
+        'runtime': {'gpio_slowdown': 4},
+        'use_short_date_format': True,
+        'double_sided': {'enabled': True, 'copies': 2, 'axis': 'horizontal'},
+        'vegas_scroll': {'enabled': True, 'auto_trim': True,
+                         'dynamic_duration_enabled': True,
+                         'continuous_scroll': True, 'smooth_scroll': True},
+    },
+}
+
+
+@pytest.fixture
+def saved(api_v3_module, monkeypatch):
+    captured = {}
+    api_v3_module.api_v3.config_manager.load_config.side_effect = \
+        lambda *a, **k: copy.deepcopy(STORED)
+
+    def fake_save(_manager, config, **_kwargs):
+        captured['config'] = config
+        return True, ''
+
+    monkeypatch.setattr(api_v3_module, '_save_config_atomic', fake_save)
+    from web_interface import auto_update
+    monkeypatch.setattr(auto_update, 'start_setup_if_needed', lambda *a, **k: None)
+    return captured
+
+
+def _post_json(client, body):
+    return client.post('/api/v3/config/main', data=json.dumps(body),
+                       content_type='application/json')
+
+
+class TestJsonPartialSaves:
+    def test_mqtt_bridge_brightness_changes_only_brightness(self, api_v3_client, saved):
+        # integrations/mqtt_bridge/ledmatrix_mqtt_bridge.py set_brightness
+        resp = _post_json(api_v3_client, {'brightness': 40})
+        assert resp.status_code == 200, resp.get_json()
+        display = saved['config']['display']
+        assert display['hardware']['brightness'] == 40
+        assert display['hardware']['disable_hardware_pulsing'] is True
+        assert display['hardware']['inverse_colors'] is True
+        assert display['hardware']['show_refresh_rate'] is True
+        assert display['use_short_date_format'] is True
+
+    def test_timezone_only_keeps_autostart_and_auto_update(self, api_v3_client, saved):
+        resp = _post_json(api_v3_client, {'timezone': 'UTC'})
+        assert resp.status_code == 200, resp.get_json()
+        config = saved['config']
+        assert config['timezone'] == 'UTC'
+        assert config['web_display_autostart'] is True
+        assert config['auto_update'] == {'enabled': True}
+
+    def test_location_only_keeps_plugin_system_toggles(self, api_v3_client, saved):
+        resp = _post_json(api_v3_client, {'city': 'Paris', 'plugins_directory': 'plugin-repos'})
+        assert resp.status_code == 200, resp.get_json()
+        assert saved['config']['plugin_system'] == {
+            'auto_discover': True, 'auto_load_enabled': True,
+            'development_mode': True, 'plugins_directory': 'plugin-repos'}
+
+    def test_vegas_speed_only_keeps_vegas_toggles(self, api_v3_client, saved):
+        resp = _post_json(api_v3_client, {'vegas_scroll_speed': 80})
+        assert resp.status_code == 200, resp.get_json()
+        vegas = saved['config']['display']['vegas_scroll']
+        assert vegas['scroll_speed'] == 80
+        for key in ('enabled', 'auto_trim', 'dynamic_duration_enabled',
+                    'continuous_scroll', 'smooth_scroll'):
+            assert vegas[key] is True, key
+
+    def test_double_sided_axis_only_keeps_enabled(self, api_v3_client, saved):
+        resp = _post_json(api_v3_client, {'double_sided_axis': 'horizontal'})
+        assert resp.status_code == 200, resp.get_json()
+        assert saved['config']['display']['double_sided']['enabled'] is True
+
+    def test_json_can_still_turn_a_checkbox_off(self, api_v3_client, saved):
+        resp = _post_json(api_v3_client, {'inverse_colors': False, 'auto_update_enabled': False})
+        assert resp.status_code == 200, resp.get_json()
+        assert saved['config']['display']['hardware']['inverse_colors'] is False
+        assert saved['config']['display']['hardware']['disable_hardware_pulsing'] is True
+        assert saved['config']['auto_update'] == {'enabled': False}
+
+    def test_json_with_charset_is_still_json(self, api_v3_client, saved):
+        resp = api_v3_client.post('/api/v3/config/main', data=json.dumps({'brightness': 41}),
+                                  content_type='application/json; charset=utf-8')
+        assert resp.status_code == 200, resp.get_json()
+        assert saved['config']['display']['hardware']['brightness'] == 41
+        assert saved['config']['display']['hardware']['inverse_colors'] is True
+
+    def test_a_non_object_body_is_refused(self, api_v3_client, saved):
+        assert _post_json(api_v3_client, [1, 2]).status_code == 400
+
+
+class TestFormSavesStillUncheck:
+    """Unchecking a box in the UI must still save false."""
+
+    def test_marked_json_form_post_unchecks_missing_display_boxes(self, api_v3_client, saved):
+        resp = _post_json(api_v3_client, {'__form_section': 'display', 'brightness': '40',
+                                          'vegas_scroll_speed': '50'})
+        assert resp.status_code == 200, resp.get_json()
+        display = saved['config']['display']
+        for key in ('disable_hardware_pulsing', 'inverse_colors', 'show_refresh_rate'):
+            assert display['hardware'][key] is False, key
+        assert display['use_short_date_format'] is False
+        assert display['vegas_scroll']['enabled'] is False
+        assert '__form_section' not in saved['config']
+
+    def test_marked_json_form_post_keeps_checked_boxes(self, api_v3_client, saved):
+        resp = _post_json(api_v3_client, {'__form_section': 'display', 'brightness': '40',
+                                          'inverse_colors': 'on'})
+        assert resp.status_code == 200, resp.get_json()
+        assert saved['config']['display']['hardware']['inverse_colors'] is True
+        assert saved['config']['display']['hardware']['show_refresh_rate'] is False
+
+    def test_marked_general_form_unchecks_autostart_and_auto_update(self, api_v3_client, saved):
+        resp = _post_json(api_v3_client, {'__form_section': 'general', 'timezone': 'UTC'})
+        assert resp.status_code == 200, resp.get_json()
+        assert saved['config']['web_display_autostart'] is False
+        assert saved['config']['auto_update'] == {'enabled': False}
+
+    def test_form_encoded_post_unchecks_missing_boxes(self, api_v3_client, saved):
+        resp = api_v3_client.post('/api/v3/config/main', data={'brightness': '40'},
+                                  content_type='application/x-www-form-urlencoded')
+        assert resp.status_code == 200, resp.get_json()
+        assert saved['config']['display']['hardware']['inverse_colors'] is False
+
+    @pytest.mark.parametrize('partial', ['general.html', 'display.html', 'durations.html'])
+    def test_every_config_main_form_carries_the_marker(self, partial):
+        html = (PARTIALS / partial).read_text(encoding='utf-8')
+        form = re.search(r'<form hx-post="/api/v3/config/main".*?</form>', html, re.S)
+        assert form, f'{partial} no longer posts to /config/main'
+        assert re.search(r'<input type="hidden" name="__form_section" value="\w+">',
+                         form.group(0)), f'{partial} form lost its __form_section marker'
+
+
+class TestVegasCycleDurations:
+    def test_cycle_durations_are_not_display_durations(self, api_v3_client, saved):
+        resp = api_v3_client.post('/api/v3/config/main', data={
+            'vegas_scroll_enabled': 'on', 'vegas_min_cycle_duration': '90',
+            'vegas_max_cycle_duration': '300'})
+        assert resp.status_code == 200, resp.get_json()
+        display = saved['config']['display']
+        assert display['vegas_scroll']['min_cycle_duration'] == 90
+        assert display['vegas_scroll']['max_cycle_duration'] == 300
+        durations = display.get('display_durations', {})
+        assert 'vegas_min_cycle_duration' not in durations
+        assert 'vegas_max_cycle_duration' not in durations
+        assert 'vegas_min_cycle_duration' not in saved['config']
+
+    def test_blank_cycle_duration_does_not_reject_the_save(self, api_v3_client, saved):
+        resp = api_v3_client.post('/api/v3/config/main', data={
+            'vegas_scroll_enabled': 'on', 'vegas_scroll_speed': '60',
+            'vegas_min_cycle_duration': ''})
+        assert resp.status_code == 200, resp.get_json()
+        assert saved['config']['display']['vegas_scroll']['scroll_speed'] == 60
+
+    def test_real_display_durations_still_save(self, api_v3_client, saved):
+        resp = _post_json(api_v3_client, {'clock_duration': '45'})
+        assert resp.status_code == 200, resp.get_json()
+        assert saved['config']['display']['display_durations']['clock_duration'] == 45
+
+
+class TestRawSaveStartsAutoUpdateSetup:
+    @pytest.fixture
+    def raw_env(self, api_v3_module, monkeypatch):
+        cm = api_v3_module.api_v3.config_manager
+        cm.get_raw_file_content.return_value = {'timezone': 'UTC', 'auto_update': {'enabled': False}}
+        calls = []
+        from web_interface import auto_update
+        monkeypatch.setattr(auto_update, 'start_setup_if_needed',
+                            lambda was, config: calls.append((was, config)) or 'Setup note.')
+        return cm, calls
+
+    def test_enabling_from_raw_json_calls_setup(self, api_v3_client, raw_env):
+        cm, calls = raw_env
+        body = {'timezone': 'UTC', 'auto_update': {'enabled': True}}
+        resp = api_v3_client.post('/api/v3/config/raw/main', json=body)
+        assert resp.status_code == 200, resp.get_json()
+        cm.save_raw_file_content.assert_called_once_with('main', body)
+        assert calls == [(False, body)]
+        assert 'Setup note.' in resp.get_json()['message']
+
+    def test_previously_enabled_is_passed_through(self, api_v3_client, raw_env):
+        cm, calls = raw_env
+        cm.get_raw_file_content.return_value = {'auto_update': {'enabled': True}}
+        body = {'auto_update': {'enabled': True}}
+        assert api_v3_client.post('/api/v3/config/raw/main', json=body).status_code == 200
+        assert calls == [(True, body)]
+
+
+class TestSchedulesAcceptTheirGetShape:
+    PER_DAY = {
+        'enabled': True, 'mode': 'per-day', 'dim_brightness': 20,
+        'days': {
+            'monday': {'enabled': True, 'start_time': '21:15', 'end_time': '06:45'},
+            'tuesday': {'enabled': False},
+            'wednesday': {'enabled': True, 'start_time': '22:00', 'end_time': '05:30'},
+            'thursday': {'enabled': True, 'start_time': '20:00', 'end_time': '07:00'},
+            'friday': {'enabled': True, 'start_time': '23:00', 'end_time': '08:00'},
+            'saturday': {'enabled': True, 'start_time': '23:30', 'end_time': '09:00'},
+            'sunday': {'enabled': True, 'start_time': '21:00', 'end_time': '07:00'},
+        },
+    }
+
+    @pytest.fixture
+    def store(self, api_v3_module, monkeypatch):
+        state = {'config': {}}
+        api_v3_module.api_v3.config_manager.load_config.side_effect = \
+            lambda *a, **k: copy.deepcopy(state['config'])
+
+        def fake_save(_manager, config, **_kwargs):
+            state['config'] = copy.deepcopy(config)
+            return True, ''
+
+        monkeypatch.setattr(api_v3_module, '_save_config_atomic', fake_save)
+        return state
+
+    @pytest.mark.parametrize('route,section,extra', [
+        ('/api/v3/config/dim-schedule', 'dim_schedule', {'dim_brightness': 20}),
+        ('/api/v3/config/schedule', 'schedule', {}),
+    ])
+    def test_get_output_posts_back_unchanged(self, api_v3_client, store, route, section, extra):
+        body = {k: v for k, v in self.PER_DAY.items() if k != 'dim_brightness'}
+        body.update(extra)
+        store['config'] = {section: copy.deepcopy(body)}
+        read = api_v3_client.get(route).get_json()['data']
+        resp = api_v3_client.post(route, json=read)
+        assert resp.status_code == 200, resp.get_json()
+        assert store['config'][section]['days'] == body['days']
+
+    def test_flat_form_keys_still_work(self, api_v3_client, store):
+        body = {'enabled': True, 'mode': 'per-day', 'dim_brightness': 25,
+                'monday_enabled': 'on', 'monday_start': '19:00', 'monday_end': '06:00'}
+        resp = api_v3_client.post('/api/v3/config/dim-schedule', json=body)
+        assert resp.status_code == 200, resp.get_json()
+        assert store['config']['dim_schedule']['days']['monday'] == {
+            'enabled': True, 'start_time': '19:00', 'end_time': '06:00'}

test/test_auto_update.py

@@ -668,7 +668,9 @@ class TestSettingsSave:
 
     def test_unchecked_toggle_on_general_save_disables(self, api_client):
         client, cm, setup_calls = api_client
-        resp = client.post('/api/v3/config/main', json={'timezone': 'UTC'})
+        # The General form marks its posts; an unchecked box is then absent.
+        resp = client.post('/api/v3/config/main',
+                           json={'__form_section': 'general', 'timezone': 'UTC'})
         assert resp.status_code == 200
         assert self._saved(cm)['auto_update'] == {'enabled': False}
         assert setup_calls == [True]

web_interface/blueprints/api_v3/config.py

@@ -14,11 +14,33 @@ from web_interface.blueprints.api_v3 import (
 from src.common.path_safety import resolve_under
 from src.pi5_matrix_support import is_raspberry_pi_5, pi5_unsupported_settings
 import web_interface.blueprints.api_v3 as _pkg
+
 # Read through the module rather than bound by value: tests patch these
 # as module attributes, and a value binding would not see the patch.
 # Several are also called from helpers that live in __init__, so the
 # package is the only patch point that covers every caller.
 
+#: Hidden input the v3 settings forms (general.html, display.html,
+#: durations.html) post to /config/main. Its presence tells save_main_config
+#: that a missing checkbox was unchecked, not merely left out of an API call.
+FORM_SECTION_FIELD = '__form_section'
+
+
+def _day_setting(data, day, flat_key, nested_key):
+    """(present, value) of one per-day schedule setting in a POST body.
+
+    The schedule forms post flat keys (``monday_start``), while GET returns
+    the stored shape, ``days.monday.start_time``. Accept both, so a client can
+    post back what it read; a flat key wins when a body carries both.
+    """
+    if flat_key in data:
+        return True, data[flat_key]
+    days = data.get('days')
+    day_config = days.get(day) if isinstance(days, dict) else None
+    if isinstance(day_config, dict) and nested_key in day_config:
+        return True, day_config[nested_key]
+    return False, None
+
 
 @api_v3.route('/config/main', methods=['GET'])
 def get_main_config():
@@ -123,8 +145,8 @@ def save_schedule_config():
                 end_key = f'{day}_end'
 
                 # Check if day is enabled
-                if enabled_key in data:
+                has_enabled, enabled_val = _day_setting(data, day, enabled_key, 'enabled')
-                    enabled_val = data[enabled_key]
+                if has_enabled:
                     # Handle checkbox values that may come as 'on', True, or False
                     if isinstance(enabled_val, str):
                         day_config['enabled'] = enabled_val.lower() in ('true', 'on', '1')
@@ -140,15 +162,8 @@ def save_schedule_config():
                     start_time = None
                     end_time = None
 
-                    if start_key in data and data[start_key]:
+                    start_time = _day_setting(data, day, start_key, 'start_time')[1] or '07:00'
-                        start_time = data[start_key]
+                    end_time = _day_setting(data, day, end_key, 'end_time')[1] or '23:00'
-                    else:
-                        start_time = '07:00'
-
-                    if end_key in data and data[end_key]:
-                        end_time = data[end_key]
-                    else:
-                        end_time = '23:00'
 
                     # Validate time formats
                     is_valid, error_msg = _validate_time_format(start_time)
@@ -352,8 +367,8 @@ def save_dim_schedule_config():
                 end_key = f'{day}_end'
 
                 # Check if day is enabled
-                if enabled_key in data:
+                has_enabled, enabled_val = _day_setting(data, day, enabled_key, 'enabled')
-                    enabled_val = data[enabled_key]
+                if has_enabled:
                     if isinstance(enabled_val, str):
                         day_config['enabled'] = enabled_val.lower() in ('true', 'on', '1')
                     else:
@@ -364,8 +379,8 @@ def save_dim_schedule_config():
                 # Only add times if day is enabled
                 if day_config.get('enabled', True):
                     enabled_days_count += 1
-                    start_time = data.get(start_key) or '20:00'
+                    start_time = _day_setting(data, day, start_key, 'start_time')[1] or '20:00'
-                    end_time = data.get(end_key) or '07:00'
+                    end_time = _day_setting(data, day, end_key, 'end_time')[1] or '07:00'
 
                     # Validate time formats
                     is_valid, error_msg = _validate_time_format(start_time)
@@ -433,8 +448,10 @@ def save_main_config():
 
         # Try to get JSON data first, fallback to form data
         data = None
-        if request.content_type == 'application/json':
+        if request.is_json:
             data = request.get_json()
+            if data is not None and not isinstance(data, dict):
+                return jsonify({'status': 'error', 'message': 'Request body must be a JSON object'}), 400
         else:
             # Handle form data
             data = request.form.to_dict()
@@ -446,6 +463,24 @@ def save_main_config():
         if not data:
             return jsonify({'status': 'error', 'message': 'No data provided'}), 400
 
+        # A missing checkbox means different things to the two kinds of caller.
+        # The settings forms post every field, and a browser leaves an
+        # unchecked box out entirely, so for them absent means False. A JSON
+        # API client (the MQTT bridge's brightness slider, a curl call from the
+        # REST docs) sends only what it is changing, and there absent means
+        # "leave it alone": treating it as unchecked turned off
+        # disable_hardware_pulsing and three other settings on every
+        # brightness change, and weekly auto-updates on every timezone change.
+        # The v3 forms post JSON too (htmx json-enc), so they identify
+        # themselves with a hidden FORM_SECTION_FIELD input. A form-encoded
+        # post is a form by definition.
+        is_form_submission = bool(data.pop(FORM_SECTION_FIELD, None)) or not request.is_json
+
+        def _set_checkbox(section, key, field):
+            """Store checkbox ``field`` as ``section[key]``, if this request sets it."""
+            if is_form_submission or field in data:
+                section[key] = _coerce_to_bool(data.get(field))
+
         # What arrives here is the config itself, and the headers carry the
         # session cookie -- neither belongs in the journal, least of all at
         # ERROR on every save. The shape of the request is the part with
@@ -465,11 +500,13 @@ def save_main_config():
                                                      'auto_update_enabled'])
 
         if is_general_update:
-            # For checkbox: if not present in data during general update, it means unchecked
+            # For checkbox: if not present in data during a general *form*
-            current_config['web_display_autostart'] = _coerce_to_bool(data.get('web_display_autostart'))
+            # update, it means unchecked (see _set_checkbox)
+            _set_checkbox(current_config, 'web_display_autostart', 'web_display_autostart')
+            if is_form_submission or 'auto_update_enabled' in data:
                 if not isinstance(current_config.get('auto_update'), dict):
                     current_config['auto_update'] = {}
-            current_config['auto_update']['enabled'] = _coerce_to_bool(data.get('auto_update_enabled'))
+                _set_checkbox(current_config['auto_update'], 'enabled', 'auto_update_enabled')
 
         if 'timezone' in data:
             current_config['timezone'] = data['timezone']
@@ -523,7 +560,7 @@ def save_main_config():
             # Handle plugin system checkboxes - always set to handle unchecked state
             # HTML checkboxes omit the key when unchecked, so missing key = unchecked = False
             for checkbox in ['auto_discover', 'auto_load_enabled', 'development_mode']:
-                current_config['plugin_system'][checkbox] = _coerce_to_bool(data.get(checkbox))
+                _set_checkbox(current_config['plugin_system'], checkbox, checkbox)
 
             # Handle plugins_directory
             if 'plugins_directory' in data:
@@ -646,10 +683,10 @@ def save_main_config():
 
             # Handle checkboxes - coerce to bool to ensure proper JSON types
             for checkbox in ['disable_hardware_pulsing', 'inverse_colors', 'show_refresh_rate']:
-                current_config['display']['hardware'][checkbox] = _coerce_to_bool(data.get(checkbox))
+                _set_checkbox(current_config['display']['hardware'], checkbox, checkbox)
 
-            # Handle display-level checkboxes (always set to handle unchecked state)
+            # Handle display-level checkboxes (unchecked state on form saves)
-            current_config['display']['use_short_date_format'] = _coerce_to_bool(data.get('use_short_date_format'))
+            _set_checkbox(current_config['display'], 'use_short_date_format', 'use_short_date_format')
 
             # Handle dynamic duration settings
             if 'max_dynamic_duration_seconds' in data:
@@ -671,8 +708,11 @@ def save_main_config():
             # checkbox, so when the feature is off we accept the values without
             # rejecting the whole save — otherwise a stale copies/chain_length
             # mismatch locks the user out of every other display setting.
+            if is_form_submission or 'double_sided_enabled' in data:
                 enabled = _coerce_to_bool(data.get('double_sided_enabled'))
                 ds_config['enabled'] = enabled
+            else:
+                enabled = _coerce_to_bool(ds_config.get('enabled'))
 
             def _copies_fits_hardware(copies: int) -> Optional[str]:
                 """Error message if copies doesn't divide the panel evenly, else None."""
@@ -742,15 +782,13 @@ def save_main_config():
             # Handle enabled checkbox
             # HTML checkboxes omit the key entirely when unchecked, so if the form
             # was submitted (any vegas field present) but enabled key is missing,
-            # the checkbox was unchecked and we should set enabled=False
+            # the checkbox was unchecked and we should set enabled=False.
-            vegas_config['enabled'] = _coerce_to_bool(data.get('vegas_scroll_enabled'))
+            # A JSON API call only changes the checkboxes it sends.
-            vegas_config['auto_trim'] = _coerce_to_bool(data.get('vegas_auto_trim'))
+            _set_checkbox(vegas_config, 'enabled', 'vegas_scroll_enabled')
-            vegas_config['dynamic_duration_enabled'] = _coerce_to_bool(
+            _set_checkbox(vegas_config, 'auto_trim', 'vegas_auto_trim')
-                data.get('vegas_dynamic_duration_enabled'))
+            _set_checkbox(vegas_config, 'dynamic_duration_enabled', 'vegas_dynamic_duration_enabled')
-            vegas_config['continuous_scroll'] = _coerce_to_bool(
+            _set_checkbox(vegas_config, 'continuous_scroll', 'vegas_continuous_scroll')
-                data.get('vegas_continuous_scroll'))
+            _set_checkbox(vegas_config, 'smooth_scroll', 'vegas_smooth_scroll')
-            vegas_config['smooth_scroll'] = _coerce_to_bool(
-                data.get('vegas_smooth_scroll'))
 
             # max_plugin_width_ratio is the one fractional setting, so it is
             # handled outside the integer loop below.
@@ -916,8 +954,12 @@ def save_main_config():
         # them AGAIN as bogus top-level config keys (e.g. "clock_duration": 30
         # sitting at config root alongside the correct
         # display.display_durations.clock_duration).
+        # The Vegas cycle-time fields (vegas_min_cycle_duration, ...) share the
+        # suffix but are Vegas settings, already handled above: counting them
+        # here wrote junk mode durations, and a blank one 400'd the save.
         duration_fields = [k for k in list(data.keys())
-                           if k.endswith('_duration') or k in ('default_duration', 'transition_duration')]
+                           if (k.endswith('_duration') and k not in vegas_fields)
+                           or k in ('default_duration', 'transition_duration')]
         if duration_fields:
             if 'display' not in current_config:
                 current_config['display'] = {}
@@ -1162,10 +1204,27 @@ def save_raw_main_config():
         if not data:
             return jsonify({'status': 'error', 'message': 'No data provided'}), 400
 
+        was_auto_update_enabled = False
+        try:
+            previous = api_v3.config_manager.get_raw_file_content('main') or {}
+            was_auto_update_enabled = bool((previous.get('auto_update') or {}).get('enabled'))
+        except Exception:
+            logger.debug("Could not read the previous auto_update setting", exc_info=True)
+
         # Save the raw config file
         api_v3.config_manager.save_raw_file_content('main', data)
 
-        return jsonify({'status': 'success', 'message': 'Main configuration saved successfully'})
+        message = 'Main configuration saved successfully'
+        # Same hook as save_main_config: switching automatic updates on here
+        # must finish their setup too, not wait for the next service restart.
+        try:
+            from web_interface import auto_update
+            note = auto_update.start_setup_if_needed(was_auto_update_enabled, data)
+            if note:
+                message = f'{message}. {note}'
+        except Exception:
+            logger.warning("Automatic update setup could not be started", exc_info=True)
+        return jsonify({'status': 'success', 'message': message})
     except Exception as e:
         from src.exceptions import ConfigError
         logger.error("Error saving raw main config", exc_info=True)

web_interface/templates/v3/partials/display.html

@@ -34,6 +34,10 @@
           class="space-y-6"
           novalidate
           onsubmit="fixInvalidNumberInputs(this); return true;">
+        {# Marks this post as the whole form, so an unchecked box saves as
+           false. Without it the save endpoint treats absent keys as unchanged
+           (FORM_SECTION_FIELD in api_v3/config.py). #}
+        <input type="hidden" name="__form_section" value="display">
 
         <!-- Hardware Settings -->
         <div class="bg-gray-50 rounded-lg p-4">

web_interface/templates/v3/partials/durations.html

@@ -15,6 +15,8 @@
           class="space-y-6"
           novalidate
           onsubmit="fixInvalidNumberInputs(this); return true;">
+        {# See general.html: identifies a whole-form post to /config/main. #}
+        <input type="hidden" name="__form_section" value="durations">
 
         <!-- Primary rotation order: drag to reorder which plugin shows first,
              second, ... in the normal display rotation. Saved as

web_interface/templates/v3/partials/general.html

@@ -30,6 +30,10 @@
               showNotification(message, status);
           "
           class="space-y-6">
+        {# Marks this post as the whole form, so an unchecked box saves as
+           false. Without it the save endpoint treats absent keys as unchanged
+           (FORM_SECTION_FIELD in api_v3/config.py). #}
+        <input type="hidden" name="__form_section" value="general">
 
         <!-- Web Display Autostart -->
         <div class="form-group" id="setting-general-web_display_autostart" data-setting-key="web_display_autostart">