CloudFront.Function: Uploading from file prefixes strange character

[peterghu]

Describe the bug

This is in C#/.NET. When creating CloudFront function from a file, the Javascript uploaded is prefixed with a strange character that prevents the function from running correctly.

Expected Behavior

Code uploaded to the CloudFront function should be exactly the same and be able to test/execute successfully.

test-mapper.js:

function handler(event) {
  var request = event.request;
  return request;
}

Current Behavior

Code is uploaded with a strange space character in front and I cannot run the function.

Function code on CloudFront Functions page:

 function handler(event) {
  var request = event.request;
  return request;
}

If I click on 'Test' and try to run the function, I get the following error: Test execution failed: InternalError

To fix it, I can manually go back to the code, delete that space character at the start, Publish and then run it successfully.

Reproduction Steps

var testFunction = new Function(this, $"{ props.StackObjectPrefix }-test-mapper", new FunctionProps
            {
                Code = FunctionCode.FromFile(new FileCodeOptions() { FilePath = "./src/MyProject/Functions/test-mapper.js" }),
                Comment = "test-mapper",
            });

test-mapper.js:

function handler(event) {
  var request = event.request;
  return request;
}

Possible Solution

File parsing in the .NET CDK must be doing something strange. If I use FromInline() and read in Javascript code using the System.IO.File class, it works as expected and does not prefix with a space character.

FunctionCode.FromInline(File.ReadAllText("./src/MyProject/Functions/test-mapper.js", System.Text.Encoding.UTF8))

Additional Information/Context

No response

CDK CLI Version

2.37.1 (build f15dee0)

Framework Version

No response

Node.js Version

16.14.2

OS

Windows 10

Language

.NET

Language Version

.Net Core 3.1

Other information

No response

[indrora]

This appears to be a UTF-8 BOM marker.

Is the original file encoded as UTF8 without BOM?

[github-actions[bot]]

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