Our test support has a TestCompiler (org.springframework.boot.testsupport.compiler.TestCompiler). Now that Spring Framework has a test module that ships with a more powerful variant, we should remove ours and adapt our existing tests.
Comment From: scottfrederick
There are a few blockers to implementing this completely right now.
One Spring Boot test compiles a class that implements a Java record. The qdox library that Framework uses to parse and validate Java source has a bug that prevents it from properly parsing records.
Most other Spring Boot tests verify some part of annotation processing, and rely on the TestCompiler invoking a javax.annotation.processing.Processor implementation. We'll need to add support for Processors to the Framework TestCompiler before migrating those tests.
Comment From: philwebb
We pretty much only use qdox now to get the fully-qualified class name. I think we could probably replace it with our own parser if we wanted.