Fix for decompiler to support templatespec

[mishrapratikshya]

This PR adds support for template spec while decompiling [#3246 ].

It add supports for the case where the id has the resourceId which is not parameterized.

            "type": "Microsoft.Resources/deployments",
            "apiVersion": "2020-10-01",
            "name": "test",
            "properties": {
                "mode": "Incremental",
                "templateLink": {
                    "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/testRg/providers/Microsoft.Resources/templateSpecs/testSpec/versions/V2"
                }
            }

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Microsoft Reviewers: Open in CodeFlow

[anthony-c-martin]

Some styling/simplification suggestions:

1. Apart from places where it's necessary, I would recommend avoiding separating the declaration & assignment of variables. For example, instead of:

   ResourceGroupLevelResourceId id;
   var templateSpec = "";
   if (ResourceGroupLevelResourceId.TryParse(templateID, out id) is not true) {
      throw  new ConversionFailedException($"Unable to parse resourceId {templateID}", resource);
   }          
   templateSpec = "ts:" + id.SubscriptionId + "/" + id.ResourceGroup + "/" + id.NameHierarchy.First() + ":" + id.NameHierarchy.Last();

   You could write:

   if (ResourceGroupLevelResourceId.TryParse(templateID, out var id) is not true) {
      throw  new ConversionFailedException($"Unable to parse resourceId {templateID}", resource);
   }          
   var templateSpec = "ts:" + id.SubscriptionId + "/" + id.ResourceGroup + "/" + id.NameHierarchy.First() + ":" + id.NameHierarchy.Last();

2. String interpolation usually offers a cleaner approach for building strings. Instead of:

   var templateSpec = "ts:" + id.SubscriptionId + "/" + id.ResourceGroup + "/" + id.NameHierarchy.First() + ":" + id.NameHierarchy.Last();

   You could write:

   var templateSpec = $"ts:{id.SubscriptionId}/{id.ResourceGroup}/{id.NameHierarchy.First()}:{id.NameHierarchy.Last()}";

3. The is not true syntax you're using is a relatively new feature for C# - pattern matching. It's really powerful for some scenarios (such as checking for null), but checking a boolean value, it's simpler and more idiomatic to just reference it directly in the if statement. Instead of:

   if (ResourceGroupLevelResourceId.TryParse(templateID, out var id) is not true) {

   You could write:

   if (!ResourceGroupLevelResourceId.TryParse(templateID, out var id)) {

[mishrapratikshya]

Updated the code. Thanks!

[anthony-c-martin]

I'd recommend restructuring this a bit (pulling your logic from line 1424 up), to cut down on the casts, usage of ?, improving variable naming, and avoiding conflating uses of the templatePathString property:

SyntaxBase modulePath;
Uri? jsonTemplateUri = null;
if (pathProperty?.Value<string>() is string templatePathString)
{
    modulePath = ...
}
else if (idProperty?.Value<string>() is string templateSpecIdString)
{
    modulePath = GetModuleFromId(templateSpecIdString, resource);
}
else
{
    throw new ConversionFailedException...
}

[mishrapratikshya]

Updated it. Thanks!

[anthony-c-martin]

This exception is going to be shown to users - could you make it more descriptive? The context of why we're trying to parse this resourceId may not be clear.

Suggestion of something like the following: "Unable to interpret \"{templateID}\" as a valid template spec resource id under property {resource["name"]}.properties.templateLink.id"

[mishrapratikshya]

Updated it. Thanks!!