codebuild: LinuxBuildImage enum does not resolve correctly

[Stephen-Meyerhofer]

Amazon.CDK.AWS.CodeBuild.LinuxBuildImage.UBUNTU_14_04_DOTNET_CORE_2_1 resolves to "aws/codebuild/ubuntu-base:14.04" instead of "aws/codebuild/dot-net:core-2.1"

[RomainMuller]

I am unable to reproduce the bad behavior using the TypeScript bindings, so it would appear to be an issue either in the .NET bindings specifically, or in jsii generally.

[RomainMuller]

Good (well, kind of) news! I can reproduce the issue on the .NET runtime, minimal repro:

using Amazon.CDK;
using Amazon.CDK.AWS.CodeBuild;

namespace Repro1027
{
    class Program
    {
        static void Main(string[] args)
        {
            var app = new App();
            var stack = new Stack(app, "TestStack", new StackProps());

            new Project(stack, "CodeBuild", new ProjectProps
                {
                    Environment = new BuildEnvironment { BuildImage = LinuxBuildImage.UBUNTU_14_04_DOTNET_CORE_2_1 }
                }
            );

            app.Run();
        }
    }
}

[RomainMuller]

The JSII_DEBUG trace shows intriguing entries:

< {"callback":{"cbid":"jsii::callback::10033","get":{"objref":{"$jsii.byref":"Object@10005"},"property":"environment"}}}
> {"complete":{"api":"complete","cbid":"jsii::callback::10033","error":"System.ArgumentException: Could not infer JSII type for .NET type 'BuildEnvironment'\nParameter name: type\n   at Amazon.JSII.Runtime.Services.Converters.FrameworkToJsiiConverter.InferType(IReferenceMap referenceMap, Type type)\n   at Amazon.JSII.Runtime.Services.Converters.ValueConverter.ConvertAny(IReferenceMap referenceMap, Object value)\n   at Amazon.JSII.Runtime.Services.Converters.ValueConverter.TryConvertPrimitive(IReferenceMap referenceMap, Object value, Boolean isOptional, PrimitiveType primitiveType, Object& result)\n   at Amazon.JSII.Runtime.Services.Converters.ValueConverter.TryConvert(TypeReference typeReference, IReferenceMap referenceMap, Object value, Object& result)\n   at Amazon.JSII.Runtime.CallbackExtensions.InvokeCallback(Callback callback, IReferenceMap referenceMap, IFrameworkToJsiiConverter converter, String& error)"}}

Apparently, the .NET JSII runtime is unable to determine the native type for the BuildEnvironment class, and this causes it to be understood as undefined, hence the build environment is always the default one.

[RomainMuller]

A part of the problem is aws/jsii#285, where another issue (which I am yet to put my finger on) in JSII should have made your CDK App crash instead of returning incorrect results.

[RomainMuller]

I reckon I've identified the bug in the C# JSII runtime that causes the incorrect behavior (aws/jsii#290).