name parameter to TypePool#describe(String) has no contract

[ljnelson]

https://github.com/raphw/byte-buddy/blob/byte-buddy-1.16.0/byte-buddy-dep/src/main/java/net/bytebuddy/pool/TypePool.java#L576-L602

The documentation says only:

name - The name of the type to describe. The name is to be written as when calling Class.getName().

When you call Class.getName(), you supply no arguments, so it's hard to know how calling it could describe the name parameter of TypePool#describe(String).

Maybe you meant, loosely, Class.forName(String)? But Class.forName("int") will fail, whereas typePool.describe("int") will succeed.

Then it appears that certain? all? only some? implementations of TypePool#describe(String) will accept Java Virtual Machine ArrayTypeSignatures, as in something like [java.lang.Integer whereas Class.forName("[java.lang.Integer") will fail. Is this name form officially supported, or just an implementation detail?

What, then, should the documentation for the name parameter of TypePool#describe(String) be?

[raphw]

The idea is that you can call the method on the class constant. For example:

MyClass.class.getName()

or

int[][][].class.getName()

Did you observe that this does not apply?

[ljnelson]

Maybe I was not clear. If I call someTypePool.describe("int"), it works; I get a TypeDescription representing int. If I call someTypePool.describe("[I"), it works; I get a TypeDescription representing int[]. If I call someTypePool.describe("[Qjava.lang.Integer!") it works; I get a TypeDescription representing java.lang.Integer[]. What do these names have in common? Where is it described what is a legal input and what is not?

[raphw]

This is indeed a sloppyness in the input validation. For a non-primitive array, it does not currently check that the input starts with an L and ends with a ; as it is done for toString on type representations, but simply cuts the first and last character.

I will add validation that it checks for well-formed input in the future.

[ljnelson]

Next up, if I wanted a TypeDescription for a nested class, do I use dollar signs or periods? e.g. typePool.describe("com.foo.Bar$Baz") or typePool.describe("com.foo.Bar.Baz")? (I know I can try it out, but I should be able to understand what is legal input and what is not from the documentation (the contract).)

[raphw]

Dollar signs, just as the toString implementation of Class. Have Class.toString as a reference.

[ljnelson]

Hmm; OK, but Class#toString() says that "class " will always be in the output. Anyway, it would be nice if the javadoc listed what rules an argument for the name parameter of the TypePool#describe(String) method needs to follow. Thanks!

[raphw]

That is true. The prefix is omitted. As if getName() was called, as the javadoc says.