From ae501048f59646fc688fe0373f938096dab5bd7f Mon Sep 17 00:00:00 2001
From: Pagan Gazzard <page@balena.io>
Date: Tue, 18 Jan 2022 11:44:40 +0000
Subject: [PATCH 1/2] Ensure the `finish` event is always reported when
 fetching images

Change-type: patch
---
 src/compose/images.ts | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/src/compose/images.ts b/src/compose/images.ts
index e57185c6..d8ca7aaf 100644
--- a/src/compose/images.ts
+++ b/src/compose/images.ts
@@ -172,7 +172,7 @@ export function imageFromService(service: ServiceInfo): Image {
 export async function triggerFetch(
 	image: Image,
 	opts: FetchOptions,
-	onFinish = _.noop,
+	onFinish: (success: boolean) => void,
 	serviceName: string,
 ): Promise<void> {
 	const appUpdatePollInterval = await config.get('appUpdatePollInterval');
@@ -202,8 +202,7 @@ export async function triggerFetch(
 	let success: boolean;
 	try {
 		const imageName = normalise(image.name);
-		image = _.clone(image);
-		image.name = imageName;
+		image = { ...image, name: imageName };
 
 		// Look for a matching image on the engine
 		const img = await inspectByName(image.name);
@@ -214,8 +213,7 @@ export async function triggerFetch(
 		// Create image on the database if it already exists on the engine
 		await markAsSupervised({ ...image, dockerImageId: img.Id });
 
-		onFinish(true);
-		return;
+		success = true;
 	} catch (e) {
 		if (!NotFoundError(e)) {
 			if (!(e instanceof ImageDownloadBackoffError)) {

From fa0e28de6d5db0329c8298ce1c8632dcd24b4d7a Mon Sep 17 00:00:00 2001
From: Felipe Lalanne <felipe@balena.io>
Date: Tue, 18 Jan 2022 14:49:03 +0000
Subject: [PATCH 2/2] Clean up image event reporting

---
 src/compose/images.ts | 35 ++++++++++++++++-------------------
 1 file changed, 16 insertions(+), 19 deletions(-)

diff --git a/src/compose/images.ts b/src/compose/images.ts
index d8ca7aaf..67f8bcb6 100644
--- a/src/compose/images.ts
+++ b/src/compose/images.ts
@@ -125,29 +125,26 @@ const runningTasks: { [imageName: string]: ImageTask } = {};
 function reportEvent(event: 'start' | 'update' | 'finish', state: Image) {
 	const { name: imageName } = state;
 
-	// Emit by default if a start event is reported
-	let emitChange = event === 'start';
-
 	// Get the current task and update it in memory
-	const currentTask =
-		event === 'start' ? createTask(state) : runningTasks[imageName];
+	const currentTask = runningTasks[imageName] ?? createTask(state);
 	runningTasks[imageName] = currentTask;
 
-	// TODO: should we assert that the current task exists at this point?
-	// On update, update the corresponding task with the new state if it exists
-	if (event === 'update' && currentTask) {
-		const [updatedTask, changed] = currentTask.update(state);
-		runningTasks[imageName] = updatedTask;
-		emitChange = changed;
-	}
+	const stateChanged = (() => {
+		switch (event) {
+			case 'start':
+				return true; // always report change on start
+			case 'update':
+				const [updatedTask, changedAfterUpdate] = currentTask.update(state);
+				runningTasks[imageName] = updatedTask;
+				return changedAfterUpdate; // report change only if the task context changed
+			case 'finish':
+				const [, changedAfterFinish] = currentTask.finish();
+				delete runningTasks[imageName];
+				return changedAfterFinish; // report change depending on the state of the task
+		}
+	})();
 
-	// On update, update the corresponding task with the new state if it exists
-	if (event === 'finish' && currentTask) {
-		[, emitChange] = currentTask.finish();
-		delete runningTasks[imageName];
-	}
-
-	if (emitChange) {
+	if (stateChanged) {
 		events.emit('change');
 	}
 }