fix(app): show download icon for shell updates (#3471)

fluxer_desktop/src/main/DesktopUpdateGate.test.mjs

@@ -25,8 +25,8 @@ function deferred() {
 
 describe('DesktopUpdateGate', () => {
 	test('nothing is available and nothing starts before the bootstrap arms the gate', async () => {
-		assert.deepEqual(getDesktopUpdateState(), {available: false, updating: false});
-		assert.deepEqual(await checkDesktopUpdateNow(), {available: false, updating: false});
+		assert.deepEqual(getDesktopUpdateState(), {available: false, updating: false, replacesShell: false});
+		assert.deepEqual(await checkDesktopUpdateNow(), {available: false, updating: false, replacesShell: false});
 		assert.equal(startDesktopUpdate(), false);
 	});
 
@@ -44,17 +44,17 @@ describe('DesktopUpdateGate', () => {
 			},
 		});
 
-		assert.deepEqual(await checkDesktopUpdateNow(), {available: true, updating: false});
+		assert.deepEqual(await checkDesktopUpdateNow(), {available: true, updating: false, replacesShell: false});
 		assert.equal(startDesktopUpdate(), true);
 		assert.equal(startDesktopUpdate(), false, 'a second click while the update runs is a no-op');
 		assert.deepEqual(
 			getDesktopUpdateState(),
-			{available: false, updating: true},
+			{available: false, updating: true, replacesShell: false},
 			'the affordance hides the moment it is clicked',
 		);
 		assert.deepEqual(
 			await checkDesktopUpdateNow(),
-			{available: false, updating: true},
+			{available: false, updating: true, replacesShell: false},
 			'a poll during the update changes nothing',
 		);
 
@@ -62,11 +62,11 @@ describe('DesktopUpdateGate', () => {
 		await new Promise((resolve) => setImmediate(resolve));
 
 		assert.equal(starts, 1);
-		assert.deepEqual(getDesktopUpdateState(), {available: false, updating: false});
+		assert.deepEqual(getDesktopUpdateState(), {available: false, updating: false, replacesShell: false});
 		assert.deepEqual(states, [
-			{available: true, updating: false},
-			{available: false, updating: true},
-			{available: false, updating: false},
+			{available: true, updating: false, replacesShell: false},
+			{available: false, updating: true, replacesShell: false},
+			{available: false, updating: false, replacesShell: false},
 		]);
 		stop();
 	});
@@ -111,7 +111,7 @@ describe('DesktopUpdateGate', () => {
 		pending.resolve();
 		await background;
 
-		assert.deepEqual(await manual, {available: true, updating: false});
+		assert.deepEqual(await manual, {available: true, updating: false, replacesShell: true});
 		assert.deepEqual(calls, [false, true]);
 	});
 
@@ -127,7 +127,7 @@ describe('DesktopUpdateGate', () => {
 		assert.equal(startDesktopUpdate(), true);
 		await new Promise((resolve) => setImmediate(resolve));
 
-		assert.deepEqual(getDesktopUpdateState(), {available: true, updating: false});
+		assert.deepEqual(getDesktopUpdateState(), {available: true, updating: false, replacesShell: true});
 		assert.equal(startDesktopUpdate(), true);
 	});
 });

fluxer_desktop/src/main/DesktopUpdateGate.ts

@@ -24,6 +24,7 @@ interface DesktopUpdateGateState {
 	checking: {readonly manual: boolean; readonly settled: Promise<void>} | null;
 	notifiedAvailable: boolean;
 	notifiedUpdating: boolean;
+	notifiedReplacesShell: boolean;
 	readonly listeners: Set<DesktopUpdateStateListener>;
 }
 
@@ -34,6 +35,7 @@ const gateState: DesktopUpdateGateState = {
 	checking: null,
 	notifiedAvailable: false,
 	notifiedUpdating: false,
+	notifiedReplacesShell: false,
 	listeners: new Set(),
 };
 
@@ -42,9 +44,11 @@ function isAvailable(check: DesktopUpdateCheck | null): boolean {
 }
 
 export function getDesktopUpdateState(): DesktopUpdateState {
+	const available = gateState.running == null && isAvailable(gateState.lastCheck);
 	return {
-		available: gateState.running == null && isAvailable(gateState.lastCheck),
+		available,
 		updating: gateState.running != null,
+		replacesShell: available && gateState.lastCheck?.shellNewer === true,
 	};
 }
 
@@ -55,11 +59,17 @@ export function desktopUpdateReplacesShell(): boolean {
 function notify(): void {
 	const state = getDesktopUpdateState();
 	const updating = state.updating === true;
-	if (state.available === gateState.notifiedAvailable && updating === gateState.notifiedUpdating) {
+	const replacesShell = state.replacesShell === true;
+	if (
+		state.available === gateState.notifiedAvailable &&
+		updating === gateState.notifiedUpdating &&
+		replacesShell === gateState.notifiedReplacesShell
+	) {
 		return;
 	}
 	gateState.notifiedAvailable = state.available;
 	gateState.notifiedUpdating = updating;
+	gateState.notifiedReplacesShell = replacesShell;
 	for (const listener of Array.from(gateState.listeners)) {
 		try {
 			listener(state);