Why is my function returning null/nil?? - Godot

Question

So, I'm trying to make a function that returns a Dictionary and for some reason it is returning Nil every time I use it. Even though all the endings are returning something! I've restarted the editor and tried some debugging, but couldn't get it to work. Here is my script and error:

Script:

func getItem(itemName:String) -> Dictionary:
    if is_name_in_inventory(itemName):
        if inventory.item1.name == itemName:
            return inventory.item1.merge({"index": 1, "error": false})
        elif inventory.item2.name == itemName:
            return inventory.item2.merge({"index": 2, "error": false})
        elif inventory.item3.name == itemName:
            return inventory.item3.merge({"index": 3, "error": false})
        elif inventory.item4.name == itemName:
            return inventory.item4.merge({"index": 4, "error": false})

        print("Unknown error finding an inventory item...")
        return {"error": true, "errormessage": ""}
    
    print("That name does not exist!")
    return {"error": true, "errormessage": "That name does not exist!"}

Error:

Invalid call. Nonexistent function 'get' in base 'Nil'

I am using the function like this: getItem("item").get("error", false)

I tried to use a function to get a Dictionary and was expecting something not nil

Answer 1

The issue is that merge is void. I quote from the official documentation on merge:

void merge ( Dictionary dictionary, bool overwrite=false )

Adds elements from dictionary to this Dictionary. By default, duplicate keys will not be copied over, unless overwrite is true.

Thus, the lines that look like this:

return inventory.item1.merge({"index": 1, "error": false})

Would:

1. modify the dictionary that you have in inventory.
2. return null.

And you don't want that.

---

You might be wondering why Godot is not complaining about this. As it turns out, it is a quirk of Godot 3 that Array and Dictionary are nullable, sometimes.

---

Anyway, you can work around it by declaring the dictionary you want to return. For example:

var result := {"index": 1, "error": false}
result.merge(inventory.item1)
return result

---

In other notes, perhaps you would benefit from making item1, item2 and so on into an Array so you can iterate over them instead of making an if for each one.