ECJ not seeing generated classes/packages but javac does

[guw]

I need help with debugging a bit of a special problem with ECJ. I am using the ECJ compiler programmatically.

I have two modes working:

1. via tool api
   https://github.com/salesforce/bazel-jdt-java-toolchain/blob/7e175dca3becc03ac4d9574382e56bee827c050f/compiler/src/main/buildjar/com/google/devtools/build/buildjar/javac/BlazeEcjToolMain.java#L99-L115

2. via extending org.eclipse.jdt.internal.compiler.batch.Main directly
   https://github.com/salesforce/bazel-jdt-java-toolchain/blob/7e175dca3becc03ac4d9574382e56bee827c050f/compiler/src/main/buildjar/com/google/devtools/build/buildjar/javac/BlazeEcjMain.java#L321-L332

The second options allows me to implement some additional features (like tracking used dependencies ore generated sources).

I am running into a weird issue now, which works in the javac but does not work with ECJ in either mode. I wonder if someone has an idea what/where to debug.

Basically I have an annotation processor that is generating some Java code. Then there is also existing .java source files to be compiled in the same run, which already reference the "to be generated" code.

It works in javac but not with the tool interface or when extending Main the compiler. It looks like ECJ is unable to resolve the generated classes and reports a compile error (The import foo.bar cannot be resolved).

[guw]

To close the loop, I found the problem:
#1654, fixed via #1447

After building a reproducible test case I was able to confirm it's fixed in 4.31RC1