Fixes issue 4243: Ensure while loop in calendar module does not get stuck when no entries

defaultmodules/calendar/calendar.js

@@ -595,9 +595,9 @@ Module.register("calendar", {
 				if (eventsByDate[dateStr] && eventsByDate[dateStr].length > 0) {
 					// If there are any events today then get all those events and select the currently active events and the events that are starting later in the day.
 					newEvents.push(...eventsByDate[dateStr].filter((ev) => this.timestampToMoment(ev.endDate).isAfter(moment())));
-					// Since we found a day with events, increase the daysCollected by 1
-					daysCollected++;
 				}
+				// Increment the daysCollected by one to ensure the while loop does not get stuck.
+				daysCollected++;
 				// Search for the next day
 				currentDate.add(1, "day");
 			}

tests/configs/modules/calendar/empty-day.js

@@ -0,0 +1,25 @@
+const config = {
+	address: "0.0.0.0",
+	ipWhitelist: [],
+	timeFormat: 12,
+
+	modules: [
+		{
+			module: "calendar",
+			position: "bottom_bar",
+			config: {
+				limitDays: 3,
+				calendars: [
+					{
+						url: "http://localhost:8080/tests/mocks/calendar_test_empty_day.ics"
+					}
+				]
+			}
+		}
+	]
+};
+
+/*************** DO NOT EDIT THE LINE BELOW ***************/
+if (typeof module !== "undefined") {
+	module.exports = config;
+}

tests/electron/modules/calendar_spec.js

@@ -96,6 +96,14 @@ describe("Calendar module", () => {
 		});
 	});
 
+	describe("Empty calendar days", () => {
+		it("shows events scheduled after an empty calendar day (issue #4243)", async () => {
+			// event is on day 3 of the limitDays:3 window, days 1-2 are intentionally empty
+			await helpers.startApplication("tests/configs/modules/calendar/empty-day.js", "01 Jan 2030 12:30:00 GMT");
+			await expect(doTestCount()).resolves.toBe(1);
+		});
+	});
+
 	/*
 	 * RRULE TESTS:
 	 * Add any tests that check rrule functionality here.

tests/mocks/calendar_test_empty_day.ics

@@ -0,0 +1,11 @@
+BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//MagicMirror//Calendar Test//EN
+BEGIN:VEVENT
+UID:empty-day-test@magicmirror
+DTSTAMP:20300101T000000Z
+DTSTART;VALUE=DATE:20300103
+DTEND;VALUE=DATE:20300104
+SUMMARY:Event after empty day
+END:VEVENT
+END:VCALENDAR