BugFix: Src map type assert fix

[barnjamin]

It turns out reading json from disk and unmarshalling it produces a float whereas the result from the API returns a uint64.

func main() {

	b, err := os.ReadFile("../sourcemap.json")
	if err != nil {
		log.Fatalf("%+v", err)
	}

	m := map[string]interface{}{}
	err = json.Unmarshal(b, &m)
	if err != nil {
		log.Fatalf("fudge: %+v", err)
	}

        // Works
	mp, err := logic.DecodeSourceMap(m)
	if err != nil {
		log.Fatalf("fudge %+v", err)
	}
	log.Printf("%+v", mp)

	client, err := algod.MakeClient("http://localhost:4001", strings.Repeat("a", 64))
	if err != nil {
		log.Fatalf("fudge: %+v", err)
	}

	var program []byte = []byte("#pragma version 6\npushint 1\npop\nint 1\nreturn")

	result, err := client.TealCompile(program).Sourcemap(true).Do(context.Background())
	if err != nil {
		log.Fatalf("Failed to compile: %+v", err)
	}

        // Doesn't work (prior to change)
	mp, err = logic.DecodeSourceMap(*result.Sourcemap)
	if err != nil {
		log.Fatalf("fudge %+v", err)
	}

	log.Printf("%+v", mp)

}

[winder]

Why are you unmarshaling to a map[string]interface{} instead of a structured object?

[winder]

Alternative:

	buf:=json.Encode(ism)
	json.Decode(buf,&sm)

[barnjamin]

Can you help me understand why this is better?

[winder]

The only reason I bring it up, is that it's easy to get things wrong with reflection. So if there's a way to avoid using it the code would be easier to reason about and less likely that there is an error. So basically, I'm asking if these are simpler alternatives.

Why are you unmarshaling to a map[string]interface{} instead of a structured object?

What I mean is you could use Unmarshal into a real type instead of map[string]interface{}, that way Unmarshal would handle all of this logic. Looking a bit closer just now, I wonder if this is even better:

func DecodeSourceMap(ism map[string]interface{}) (SourceMap, error) {
  buf := json.Encode(ism)
  var sourcemap SourceMap
  return json.Decode(buf, sourcemap)
}

[barnjamin]

I can do that to begin with to set the fields specified but I still need to do some post-processing to decode the VLQ values. Is it worth it?

[winder]

I think it is, but not enough to block your PR so I'll leave it up to you.

[barnjamin]

I'm going to merge this and post a follow up with the above since I think this is tripping folks up right now

[barnjamin]

@winder

Why are you unmarshaling to a map[string]interface{} instead of a structured object?

You mean why does this method accept a map[string]interface{} ? If so, its just what we get from the call to compile endpoint: https://github.com/algorand/go-algorand-sdk/blob/develop/client/v2/common/models/compile_response.go#L12