fix(schemas): yaml schemas sometimes are not applied to cfn/sam files #2671

Problem:
When loading cloudformation files, the validation checks the "Resources" field
in the YAML and see if serverless function exists and then validate those
resources, make sure handlers, codeUri, etc are available before loading in the
schema which doesn't really make sense.

This can cause the cloudformation.load() to fail, resulting in the schema not
getting applied to the cfn/sam yaml files when it should be.

Solution:
Skip one of the validation steps. The net result is that now we only check that
`AWSTemplateFormatVersion` or `Resources` fields exist.

Author: jpinkney-aws

.changes/next-release/Bug Fix-4ce9962e-2b34-4e0b-9201-d23e0c5e7901.json

@@ -0,0 +1,4 @@
+{
+	"type": "Bug Fix",
+	"description": "Fix issue where occasionally yaml schemas weren't getting loaded for cfn/sam"
+}

src/shared/cloudformation/cloudformation.ts

@@ -365,7 +365,7 @@ export namespace CloudFormation {
         [key: string]: Resource | undefined
     }
 
-    export async function load(filename: string): Promise<Template> {
+    export async function load(filename: string, validate: boolean = true): Promise<Template> {
         if (!(await SystemUtilities.fileExists(filename))) {
             throw new Error(`Template file not found: ${filename}`)
         }
@@ -374,7 +374,10 @@ export namespace CloudFormation {
         const template = yaml.load(templateAsYaml, {
             schema: schema as any,
         }) as Template
-        validateTemplate(template)
+
+        if (validate) {
+            validateTemplate(template)
+        }
 
         return template
     }

src/shared/cloudformation/templateRegistry.ts

@@ -28,7 +28,7 @@ export class CloudFormationTemplateRegistry extends WatchedFiles<CloudFormation.
 
         let template: CloudFormation.Template | undefined
         try {
-            template = await CloudFormation.load(path)
+            template = await CloudFormation.load(path, false)
         } catch (e) {
             globals.schemaService.registerMapping({ path, type: 'yaml', schema: undefined })
             return undefined

src/test/shared/cloudformation/cloudformation.test.ts

@@ -151,6 +151,24 @@ describe('CloudFormation', function () {
             const template = await CloudFormation.load(filename)
             assert.strictEqual(template.Resources!['TestResource']?.Properties?.CodeUri, '')
         })
+
+        it('Loads invalid YAML when validation is disabled', async function () {
+            // handler is missing
+            const invalidYamlStr: string = `AWSTemplateFormatVersion: "2010-09-09"
+Transform: AWS::Serverless-2016-10-31
+Resources:
+    TestResource:
+        Type: ${CloudFormation.SERVERLESS_FUNCTION_TYPE}
+        Properties:
+            CodeUri: asdf
+            Runtime: runtime
+            Timeout: 1
+            Environment:
+                Variables:
+                    ENVVAR: envvar`
+            await strToYamlFile(invalidYamlStr, filename)
+            await assert.doesNotReject(CloudFormation.load(filename, false))
+        })
     })
 
     describe('save', async function () {