SAM local commands misbehave for CDK Templates synthesized in PowerShell

Description

Operating on a Windows machine and using a Powershell terminal, when a user synthesizes a template from an AWS-CDK application, the output template does not behave as expected when invoking sam local commands.

Steps to reproduce

1. Open a Powershell terminal
2. Set the default out file encoding to utf8. See #1628 for details.

$PSDefaultParameterValues[‘Out-File:Encoding’] = ‘utf8’

1. Synthesize a template from a CDK application.

cdk synth > template.yml

1. Invoke a sam local command

sam local invoke MyFunction3BAA72D1 --debug

Observed result

The sam local commands fail with the error message

Error: [InvalidTemplateException(“‘Resources’ section is required”)] ‘Resources’ section is required

Expected result

I expected the lambda function to be executed in a container.

Additional environment details (Ex: Windows, Mac, Amazon Linux etc)

1. OS: Windows 10 Enterprise
2. sam --version: 0.41.0
3. node: 12.14.1
4. python 3.6.5

Interestingly when I synthesized the template from Git Bash instead of PowerShell, the sam local commands appeared to work as expected.

[CoshUS]

Possible Causes: Error: [InvalidTemplateException(“‘Resources’ section is required”)] ‘Resources’ section is required

UTF-8 BOM is included in the first line with “Resources”. The section name becomes “0xEF 0xBB 0xBF Resources:”.

Error: Failed to parse template: unacceptable character #x0000: special characters are not allowed in “<unicode string>”, position 3

Template is encoded in UTF-16 instead of UTF-8

[conork-datacom]

Any update on this? I get the following error when synthesizing a CDK template to be consumed by AWS SAM with Powershell via VSCode (on Win10)

Error: Failed to parse template: unacceptable character #x0000: special characters are not allowed in "<unicode string>", position 3

Works fine running the same commands in command prompt

SAM version : 0.49.0 CDK version: 1.51.0