fix: accept colon-less +0100 last_updated in is_running() on Python 3.9/3.10

apps/predbat/predbat.py

@@ -77,6 +77,7 @@
 from config import APPS_SCHEMA, CONFIG_ITEMS
 import debug_history
 from utils import (
+    str2time,
     minutes_since_yesterday,
     minutes_since_midnight,
     dp1,
@@ -1984,8 +1985,14 @@ def is_running(self):
             return False
 
         try:
-            predbat_last_updated = datetime.fromisoformat(predbat_last_updated)
-        except ValueError:
+            try:
+                predbat_last_updated = str2time(predbat_last_updated)
+            except ValueError:
+                # str2time() requires a timezone offset, so a legacy naive last_updated (written
+                # before record_status() went timezone-aware) lands here - fall back to the
+                # naive-tolerant parser and let the tzinfo check below handle it (#5181).
+                predbat_last_updated = datetime.fromisoformat(predbat_last_updated)
+        except (ValueError, TypeError):
             return False
 
         # Check if the last updated time is within the last 15 minutes. An install upgraded

apps/predbat/tests/test_web_functions.py

@@ -10,7 +10,9 @@
 
 import asyncio
 import os
+from datetime import datetime, timezone
 
+import predbat as predbat_module
 from web import WebInterface, is_data_numerical
 from web_helper import get_plan_renderer_js
 
@@ -221,6 +223,47 @@ def set_exporting(on):
             print(f"  ERROR: expected is_running() False for a stale (2026-07-10) aware last_updated, got: {result}")
             failed += 1
 
+    # A fresh last_updated must report running in every format the attribute can hold:
+    # the colon-less +0100 that record_status() writes (strftime('%z') never emits a colon,
+    # which datetime.fromisoformat() only accepts from Python 3.11 - issue #5181), the
+    # colon form, and the legacy naive form. Naive must still reach the naive-now branch
+    # rather than being rejected as unparseable.
+    now_local = datetime.now(timezone.utc).astimezone()
+    fresh_formats = {
+        "colon-less offset (record_status writer format)": now_local.strftime("%Y-%m-%dT%H:%M:%S%z"),
+        "colon offset": now_local.isoformat(),
+        "naive legacy": str(datetime.now()),
+    }
+    # The Python that CI runs accepts all three formats through datetime.fromisoformat() alone,
+    # so also check that is_running() hands the value to str2time() - without that, reverting
+    # the fix would leave these cases passing everywhere except Python 3.9/3.10.
+    original_str2time = predbat_module.str2time
+    str2time_calls = []
+
+    def str2time_spy(time_str):
+        str2time_calls.append(time_str)
+        return original_str2time(time_str)
+
+    predbat_module.str2time = str2time_spy
+    try:
+        for label, stamp in fresh_formats.items():
+            set_entity(my_predbat, status_entity, state="Idle", error=False, last_updated=stamp)
+            del str2time_calls[:]
+            try:
+                result = my_predbat.is_running()
+            except (TypeError, ValueError) as e:
+                print(f"  ERROR: is_running() raised on a fresh {label} ({stamp}): {e}")
+                failed += 1
+            else:
+                if result is not True:
+                    print(f"  ERROR: expected is_running() True for a fresh {label} ({stamp}), got: {result}")
+                    failed += 1
+                if str2time_calls != [stamp]:
+                    print(f"  ERROR: expected is_running() to parse a fresh {label} ({stamp}) with str2time(), got calls: {str2time_calls}")
+                    failed += 1
+    finally:
+        predbat_module.str2time = original_str2time
+
     my_predbat.dashboard_index = original_dashboard_index
     my_predbat.stop_thread = original_stop_thread
     my_predbat.fatal_error = original_fatal_error