Storing a reference to a DataType in the database, or "What is a UniversalID?"

[fmagin]

I have analyzers that generate information that is effectively a data type associated with an address, and I want to store them in a reliable way across restarts [0].

Identifying them via their name seems brittle given that users might change the name of a data type. The DataType interface has a getUniversalID method, that sounds like it's what I need, but this is null for most types, so I'm not sure what the point of this is.

Is there some other API to achieve this? Or do I have to store references to the DataType object during runtime, and then serialize that to a name when Ghidra closes it, and then reload it later?

[0] My plan for that is to use a UserPropertyMap for whatever primitive type makes this work, i.e. Long if I store an ID, or String if it's a path and name

[astrelsky]

Try DataTypeManager.getID(DataType) the value should always be valid if the type is from that manager.

I'm pretty sure I have used the UniversalID in the past and have never seen it be null before.

[fmagin]

The method on the DataTypeManager sounds also interesting, and like something where I would like to understand the difference to the UniversalID

Thanks to your assertion that you never saw this be null I looked deeper into it:
Turns out it's always null for array or pointer types (which kind of makes sense), the actual structs behind the pointer that I care about have universal IDs.