fix

Author: adpi2

sbt-bridge/src/xsbt/CompilerInterface.java

@@ -22,7 +22,13 @@ public CachedCompiler newCompiler(String[] options, Output output, Logger initia
     if(isClassLoaderValid()) {
       return new CachedCompilerImpl(options, output);
     } else {
-      initialLog.warn(() -> "The compiler class loader is badly configured.");
+      initialLog.warn(() ->
+        "The compiler class loader is badly configured.\n" +
+        "Consider using a more recent version of your build tool:\n" +
+        " - sbt >= 1.4.0\n" +
+        " - Mill >= 0.9.3-21-002361\n" +
+        " - Bloop >= 1.4.6-23-20a501bc"
+      );
       // To workaround the wrong class loader, we construct our own and run
       // the following code with it:
       //   new CachedCompilerImpl(options, output)
@@ -37,7 +43,7 @@ public CachedCompiler newCompiler(String[] options, Output output, Logger initia
     }
   }
 
-  private Boolean isClassLoaderValid() {
+  private boolean isClassLoaderValid() {
     // Check that the `xsbti.*` classes are loaded from the same class loader in the compiler and the bridge
     ClassLoader compilerClassLoader = Main.class.getClassLoader();
     Class<Logger> clazz = Logger.class;