Java: Support CompileTimeConstantExpr for constant fields from compiled classes

[Marcono1234]

When compiled classes have constant fields, source code referencing them uses the constant value. A simple example for this is the following:

class ConstantTest {
    static final int VALUE = Integer.MAX_VALUE;
}

Compiling this class and inspecting it with javap -v shows that the value of Integer.MAX_VALUE, that is 2147483647, has been stored in the class file (instead of performing a field read). This is also explicitly mentioned in JLS 17 §13.4.9.

Currently CodeQL's CompileTimeConstantExpr does not support this; I assume because the information is missing from the database. Would it be possible to store this information in the database during extraction?

[aschackmull]

This is definitely something that would be nice to have. I don't currently know how easy it would be to extend the extractor to capture this information.