fix: lambda layer change handling

packages/amplify-category-function/src/provider-utils/awscloudformation/service-walkthroughs/lambdaLayerWalkthrough.ts

@@ -113,7 +113,7 @@ export async function updateLayerWalkthrough(
 
     // select layer version
     if (layerHasDeployed) {
-      const layerCloudState = LayerCloudState.getInstance();
+      const layerCloudState = LayerCloudState.getInstance(parameters.layerName);
       const layerVersions = await layerCloudState.getLayerVersionsFromCloud(context, parameters.layerName);
       const latestVersionText = 'Future layer versions';
       const layerVersionChoices = [

packages/amplify-category-function/src/provider-utils/awscloudformation/service-walkthroughs/removeLayerWalkthrough.ts

@@ -11,7 +11,7 @@ import { updateLayerArtifacts } from '../utils/storeResources';
 const removeLayerQuestion = 'Choose the Layer versions you want to remove.';
 
 export async function removeWalkthrough(context: $TSContext, layerName: string): Promise<string | undefined> {
-  const layerCloudState = LayerCloudState.getInstance();
+  const layerCloudState = LayerCloudState.getInstance(layerName);
   const layerVersionList = await layerCloudState.getLayerVersionsFromCloud(context, layerName);
 
   // if the layer hasn't been pushed return and remove it

packages/amplify-category-function/src/provider-utils/awscloudformation/utils/addLayerToFunctionUtils.ts

@@ -65,7 +65,7 @@ export const askLayerSelection = async (
   layerSelections = layerSelections.filter(selection => selection !== provideExistingARNsPrompt);
 
   for (const layerName of layerSelections) {
-    const layerCloudState = LayerCloudState.getInstance();
+    const layerCloudState = LayerCloudState.getInstance(layerName);
     const layerVersions = await layerCloudState.getLayerVersionsFromCloud(context, layerName);
     const layerVersionChoices = layerVersions.map(mapVersionNumberToChoice);
 
@@ -83,10 +83,16 @@ export const askLayerSelection = async (
       const previousLayerSelection = _.first(filterProjectLayers(previousSelections).filter(prev => prev.resourceName === layerName));
 
       let defaultLayerSelection: string;
+
       if (previousLayerSelection === undefined || previousLayerSelection.isLatestVersionSelected) {
         defaultLayerSelection = defaultLayerVersionPrompt;
       } else {
-        defaultLayerSelection = mapVersionNumberToChoice(_.first(layerVersions.filter(v => v.Version === previousLayerSelection.version)));
+        const previouslySelectedLayerVersion = _.first(layerVersions.filter(v => v.Version === previousLayerSelection.version));
+
+        // Fallback to defaultLayerVersionPrompt as it is possible that a function is associated with a non-existent layer version
+        defaultLayerSelection = previouslySelectedLayerVersion
+          ? mapVersionNumberToChoice(previouslySelectedLayerVersion)
+          : defaultLayerVersionPrompt;
       }
 
       const versionSelection = (

packages/amplify-category-function/src/provider-utils/awscloudformation/utils/lambda-layer-cloudformation-template.ts

@@ -24,8 +24,8 @@ export function generateLayerCfnObj(isNewVersion: boolean, parameters: LayerPara
   if (isNewVersion) {
     const [shortId] = uuid().split('-');
     logicalName = `${LayerCfnLogicalNamePrefix.LambdaLayerVersion}${shortId}`;
-    const layerCloudState = LayerCloudState.getInstance();
-    layerCloudState.latestVersionLogicalId = logicalName; // Store in singleton so it can be used in zipfile name
+    const layerCloudState = LayerCloudState.getInstance(parameters.layerName);
+    layerCloudState.latestVersionLogicalId = logicalName; // Store in the given layer's layerCloudState instance so it can be used in zipfile name
     versionList.unshift({ LogicalName: logicalName, legacyLayer: false });
   } else {
     logicalName = _.first(versionList).LogicalName;

packages/amplify-category-function/src/provider-utils/awscloudformation/utils/layerCloudState.ts

@@ -6,17 +6,17 @@ import { LegacyPermissionEnum } from './layerMigrationUtils';
 import { LayerVersionMetadata, PermissionEnum } from './layerParams';
 
 export class LayerCloudState {
-  private static instance: LayerCloudState;
+  private static instances: Record<string, LayerCloudState> = {};
   private layerVersionsMetadata: LayerVersionMetadata[];
   public latestVersionLogicalId: string;
 
   private constructor() {}
 
-  static getInstance(): LayerCloudState {
-    if (!LayerCloudState.instance) {
-      LayerCloudState.instance = new LayerCloudState();
+  static getInstance(layerName: string): LayerCloudState {
+    if (!LayerCloudState.instances[layerName]) {
+      LayerCloudState.instances[layerName] = new LayerCloudState();
     }
-    return LayerCloudState.instance;
+    return LayerCloudState.instances[layerName];
   }
 
   private async loadLayerDataFromCloud(context: $TSContext, layerName: string): Promise<LayerVersionMetadata[]> {

packages/amplify-category-function/src/provider-utils/awscloudformation/utils/packageLayer.ts

@@ -60,10 +60,10 @@ export const packageLayer: Packager = async (context, resource) => {
     await zipPackage(packageResult.zipEntries, destination);
   }
 
-  const layerCloudState = LayerCloudState.getInstance();
+  const layerCloudState = LayerCloudState.getInstance(resource.resourceName);
   if (!layerCloudState.latestVersionLogicalId) {
     // "Should" never be reachable, but sanity check just in case
-    throw new Error('LogicalId missing for new layer version.');
+    throw new Error(`LogicalId missing for new layer version: ${resource.resourceName}.`);
   }
 
   const zipFilename = createLayerZipFilename(resource.resourceName, layerCloudState.latestVersionLogicalId);
@@ -112,6 +112,9 @@ export async function checkContentChanges(context: $TSContext, layerResources: A
     for (const layer of changedLayerResources) {
       let { parameters } = layer;
       if (!accepted) {
+        context.print.info('');
+        context.print.info(`Change options layer: ${layer.resourceName}`);
+        context.print.info('');
         parameters = await lambdaLayerNewVersionWalkthrough(parameters, timestampString);
       } else {
         parameters.description = `Updated layer version ${timestampString}`;

packages/amplify-category-function/src/provider-utils/awscloudformation/utils/storeResources.ts

@@ -213,14 +213,17 @@ function ensureLayerRuntimeFolder(layerDirPath: string, runtime: LayerRuntime) {
 }
 
 function createLayerCfnFile(parameters: LayerParameters, layerDirPath: string) {
-  JSONUtilities.writeJson(path.join(layerDirPath, getCfnTemplateFileName(parameters.layerName)), generateLayerCfnObj(true, parameters));
+  const layerCfnObj = generateLayerCfnObj(true, parameters);
+  const layerCfnFilePath = path.join(layerDirPath, getCfnTemplateFileName(parameters.layerName));
+
+  JSONUtilities.writeJson(layerCfnFilePath, layerCfnObj);
 }
 
 async function updateLayerCfnFile(context: $TSContext, parameters: LayerParameters, layerDirPath: string): Promise<$TSObject> {
   let layerVersionList: LayerVersionMetadata[] = [];
 
   if (loadPreviousLayerHash(parameters.layerName)) {
-    const layerCloudState = LayerCloudState.getInstance();
+    const layerCloudState = LayerCloudState.getInstance(parameters.layerName);
 
     layerVersionList = await layerCloudState.getLayerVersionsFromCloud(context, parameters.layerName);
   }