fix(fetch): compute dawn sensor regardless of combine_charge_slots

apps/predbat/fetch.py

@@ -920,12 +920,13 @@ def fetch_pv_forecast_and_dawn(self):
         # Stored on self, not just local, so it can be used elsewhere rather than only by the
         # window split below.
         pv_light_dark = self.pv_light_dark = self.calc_pv_light_dark()
-        # "on" past dawn, "off" before it or when unclassified (combine_charge_slots off, or no
-        # PV forecast) - not the same as PV actually producing right now, see calc_dawn's docstring
+        # "on" past dawn, "off" before it or when unclassified (no PV forecast) - based on the PV
+        # forecast crossing low_power_pv_threshold_w, not the same as PV actually producing right
+        # now, see calc_dawn's docstring. Independent of combine_charge_slots/set_charge_low_power.
         self.dashboard_item(
             "binary_sensor." + self.prefix + "_dawn",
             state="on" if pv_light_dark.get(self.minutes_now) == 1 else "off",
-            attributes={"friendly_name": "Predbat is past dawn (light, not dark, in the low-power charge window split)", "icon": "mdi:weather-sunset-up"},
+            attributes={"friendly_name": "Predbat is past dawn (light, not dark, by PV forecast)", "icon": "mdi:weather-sunset-up"},
         )
         return pv_light_dark
 
@@ -1902,19 +1903,18 @@ def carbon_replicate(self, carbon_data):
 
     def calc_pv_light_dark(self):
         """
-        Decide whether a dawn light/dark boundary is worth computing at all, and return it via
-        calc_dawn if so - otherwise an empty dict (no split).
+        Compute the dawn light/dark split via calc_dawn().
 
-        Only combine_charge_slots can merge a charge window across dawn in the first place - with it
-        off, find_charge_window already forces a break every charge_slot_split minutes (which equals
-        plan_interval_minutes, the same granularity calc_dawn buckets at), so the dawn boundary could
-        never be reached and computing it would be a pure no-op. This used to be gated on
-        set_charge_low_power instead, since that was the only feature that needed the split - but the
-        split also lets the plan optimizer charge just the dark portion of a combined window and skip
-        the daylight portion (where solar may cover the load) on its own merits, independent of low
-        power charging, so it now runs for any combine_charge_slots user.
+        Always computed, even when combine_charge_slots is off: with it off, find_charge_window
+        already forces a window break every charge_slot_split minutes (which equals
+        plan_interval_minutes, the same granularity calc_dawn buckets at), so the dawn boundary can
+        never actually be reached there and calc_dawn's result is a no-op for window splitting in
+        that case - but binary_sensor.predbat_dawn (published from this same result, see
+        fetch_pv_forecast_and_dawn) is a useful standalone signal regardless of combine_charge_slots,
+        and used to read permanently "off" for anyone with it disabled (the default) even in broad
+        daylight, which is what it is not meant to mean.
         """
-        return self.calc_dawn() if self.combine_charge_slots else {}
+        return self.calc_dawn()
 
     def calc_dawn(self):
         """

apps/predbat/tests/test_find_charge_window.py

@@ -503,17 +503,14 @@ def set_buckets(bucket_values):
 
 def test_calc_pv_light_dark(my_predbat):
     """
-    Tests for calc_pv_light_dark: decides whether calc_dawn is worth computing at all.
-
-    Only combine_charge_slots can merge a charge window across dawn, so that's what gates the split -
-    not set_charge_low_power. With combine_charge_slots off, find_charge_window already forces a break
-    every charge_slot_split (=plan_interval_minutes) minutes regardless, so the dawn boundary could
-    never be reached and computing it would be a no-op:
-
-      - combine_charge_slots=True, set_charge_low_power=False -> dawn split still runs (the new case -
-        the optimizer can pick the dark portion of a combined window on its own merits)
-      - combine_charge_slots=True, set_charge_low_power=True -> dawn split runs (unchanged behaviour)
-      - combine_charge_slots=False, regardless of set_charge_low_power -> {} (moot, skipped)
+    Tests for calc_pv_light_dark: always returns calc_dawn's result.
+
+    calc_dawn is computed regardless of combine_charge_slots or set_charge_low_power -
+    binary_sensor.predbat_dawn (published from this same result) is a useful standalone light/dark
+    signal even when neither feature is enabled, and used to read permanently "off" whenever
+    combine_charge_slots was off (the default), which is not what the sensor is meant to mean. The
+    combine_charge_slots gate on window-splitting itself lives in find_charge_window instead, where it
+    is moot anyway (a break every charge_slot_split minutes already happens there regardless).
     """
     failed = 0
     old_pv_forecast_minute = my_predbat.pv_forecast_minute
@@ -528,38 +525,17 @@ def test_calc_pv_light_dark(my_predbat):
     for m in range(30, 60, 5):
         my_predbat.pv_forecast_minute[m] = 1.0  # light, crosses the threshold
 
-    print("Test calc_pv_light_dark: combine_charge_slots=True, set_charge_low_power=False -> dawn split still runs")
-    my_predbat.combine_charge_slots = True
-    my_predbat.set_charge_low_power = False
-    result = my_predbat.calc_pv_light_dark()
-    if result != my_predbat.calc_dawn():
-        print("ERROR: calc_pv_light_dark: expected calc_dawn's result when combine_charge_slots is True, got {}".format(result))
-        failed = 1
-    if result.get(0) != 0 or result.get(30) != 1:
-        print("ERROR: calc_pv_light_dark: expected a dark->light split at minute 30, got {}".format({m: result.get(m) for m in (0, 30)}))
-        failed = 1
-
-    print("Test calc_pv_light_dark: combine_charge_slots=True, set_charge_low_power=True -> dawn split runs")
-    my_predbat.set_charge_low_power = True
-    result = my_predbat.calc_pv_light_dark()
-    if result != my_predbat.calc_dawn():
-        print("ERROR: calc_pv_light_dark: expected calc_dawn's result when combine_charge_slots is True, got {}".format(result))
-        failed = 1
-
-    print("Test calc_pv_light_dark: combine_charge_slots=False, set_charge_low_power=True -> {} (moot, skipped)")
-    my_predbat.combine_charge_slots = False
-    my_predbat.set_charge_low_power = True
-    result = my_predbat.calc_pv_light_dark()
-    if result != {}:
-        print("ERROR: calc_pv_light_dark: expected {{}} when combine_charge_slots is False, got {}".format(result))
-        failed = 1
-
-    print("Test calc_pv_light_dark: combine_charge_slots=False, set_charge_low_power=False -> {}")
-    my_predbat.set_charge_low_power = False
-    result = my_predbat.calc_pv_light_dark()
-    if result != {}:
-        print("ERROR: calc_pv_light_dark: expected {{}} when combine_charge_slots is False, got {}".format(result))
-        failed = 1
+    for combine_charge, low_power in ((True, False), (True, True), (False, True), (False, False)):
+        print("Test calc_pv_light_dark: combine_charge_slots={}, set_charge_low_power={} -> dawn split always runs".format(combine_charge, low_power))
+        my_predbat.combine_charge_slots = combine_charge
+        my_predbat.set_charge_low_power = low_power
+        result = my_predbat.calc_pv_light_dark()
+        if result != my_predbat.calc_dawn():
+            print("ERROR: calc_pv_light_dark: expected calc_dawn's result, got {}".format(result))
+            failed = 1
+        if result.get(0) != 0 or result.get(30) != 1:
+            print("ERROR: calc_pv_light_dark: expected a dark->light split at minute 30, got {}".format({m: result.get(m) for m in (0, 30)}))
+            failed = 1
 
     my_predbat.pv_forecast_minute = old_pv_forecast_minute
     my_predbat.plan_interval_minutes = old_plan_interval

docs/output-data.md

@@ -703,7 +703,7 @@ The solar sensor attributes include:
 - remaining/remaining10/remaining90/remainingCL - forecast solar generation for the remainder of the day
 - detailedForecast - a half hourly breakdown of solar forecast for the day, with similar PV estimate, 10% estimate, 90% estimate and calibrated estimate values
 
-- binary_sensor.predbat_dawn - Set to 'on' when the current time is past dawn (forecast solar power at or above [low_power_pv_threshold_w](customisation.md#inverter-control-options)), 'off' before dawn or when the underlying split (which requires **switch.predbat_combine_charge_slots**) isn't in use. This reflects the same dawn boundary Predbat uses to split a low-power charge window at sunrise, not whether solar is producing enough to be useful right now.
+- binary_sensor.predbat_dawn - Set to 'on' when the current time is past dawn (forecast solar power at or above [low_power_pv_threshold_w](customisation.md#inverter-control-options)), 'off' before dawn or when no PV forecast is available. This reflects the same dawn boundary Predbat uses to split a low-power charge window at sunrise, not whether solar is producing enough to be useful right now.
 
 ## Dummy inverter sensors