Improve error message in LazyClassGen.getJavaClassBytesIncludingReweavable

No longer report "Unable to find ASM classes", if simply an ASM
processing error occurred. In that case, report "Error processing
class file".

Relates to #250.

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>

3 files changed, 17 insertions, 11 deletions

diff --git a/weaver/src/main/java/org/aspectj/weaver/bcel/LazyClassGen.java b/weaver/src/main/java/org/aspectj/weaver/bcel/LazyClassGen.java
index 61ebfb7cf..0a21db2c9 100644
--- a/weaver/src/main/java/org/aspectj/weaver/bcel/LazyClassGen.java
+++ b/weaver/src/main/java/org/aspectj/weaver/bcel/LazyClassGen.java
@@ -753,14 +753,20 @@ public final class LazyClassGen {
 		// are required (unless turning off the verifier)
 		if ((myGen.getMajor() == Constants.MAJOR_1_6 && world.shouldGenerateStackMaps()) || myGen.getMajor() > Constants.MAJOR_1_6) {
 			if (!AsmDetector.isAsmAround) {
-				// Fix https://github.com/eclipse-aspectj/aspectj/issues/251, using "replace('Ä', 'Ö')" to avoid non-relocated
-				// class names to be embedded into the error message during compile time, making it end up in the class constant
-				// pool unwantedly, as this clashes with post-compile ASM package relocation.
-				final String errorMessage = "Unable to find ASM classes (" +
-					AsmDetector.CLASS_READER.replace('Ä', 'Ö') + ", " + AsmDetector.CLASS_VISITOR.replace('Ä', 'Ö') + ") " +
-					"for stackmap generation. Stackmap generation for woven code is required to avoid verify errors " +
-					"on a Java 1.7 or higher runtime.";
-				throw new BCException(errorMessage, AsmDetector.reasonAsmIsMissing);
+				if (
+					AsmDetector.rootCause instanceof ClassNotFoundException ||
+						AsmDetector.rootCause instanceof NoClassDefFoundError
+				) {
+					// Fix https://github.com/eclipse-aspectj/aspectj/issues/251, using "replace('Ä', 'Ö')" to avoid
+					// non-relocated class names to be embedded into the error message during compile time, making it end up in
+					// the class constant pool unwantedly, as this clashes with post-compile ASM package relocation.
+					String errorMessage = "Unable to find ASM classes (" +
+						AsmDetector.CLASS_READER.replace('Ä', 'Ö') + ", " + AsmDetector.CLASS_VISITOR.replace('Ä', 'Ö') + ") " +
+						"for stackmap generation. Stackmap generation for woven code is required to avoid verify errors " +
+						"on a Java 1.7 or higher runtime.";
+					throw new BCException(errorMessage, AsmDetector.rootCause);
+				}
+				throw new BCException("Error processing class file", AsmDetector.rootCause);
 			}
 			wovenClassFileData = StackMapAdder.addStackMaps(world, myGen.getClassName(), wovenClassFileData);
 		}
diff --git a/weaver/src/main/java/org/aspectj/weaver/bcel/asm/AsmDetector.java b/weaver/src/main/java/org/aspectj/weaver/bcel/asm/AsmDetector.java
index a12a5617e..09177511c 100644
--- a/weaver/src/main/java/org/aspectj/weaver/bcel/asm/AsmDetector.java
+++ b/weaver/src/main/java/org/aspectj/weaver/bcel/asm/AsmDetector.java
@@ -20,7 +20,7 @@ public class AsmDetector {
 	public static final String CLASS_READER = "org.objectweb.asm.ClassReader";
 	public static final String CLASS_VISITOR = "org.objectweb.asm.ClassVisitor";
 	public static boolean isAsmAround;
-	public static Throwable reasonAsmIsMissing;
+	public static Throwable rootCause;
 
 	static {
 		try {
@@ -30,7 +30,7 @@ public class AsmDetector {
 			isAsmAround = true;
 		} catch (Exception e) {
 			isAsmAround = false;
-			reasonAsmIsMissing = e;
+			rootCause = e;
 		}
 		//System.out.println(isAsmAround ? "ASM detected" : "No ASM found");
 	}
diff --git a/weaver/src/main/java/org/aspectj/weaver/bcel/asm/StackMapAdder.java b/weaver/src/main/java/org/aspectj/weaver/bcel/asm/StackMapAdder.java
index ae22ed067..1c742cd08 100644
--- a/weaver/src/main/java/org/aspectj/weaver/bcel/asm/StackMapAdder.java
+++ b/weaver/src/main/java/org/aspectj/weaver/bcel/asm/StackMapAdder.java
@@ -49,7 +49,7 @@ public class StackMapAdder {
 			System.err.println("AspectJ Internal Error: unable to add stackmap attributes to class '"+classname+"'. " + t.getMessage());
 			t.printStackTrace();
 			AsmDetector.isAsmAround = false;
-			AsmDetector.reasonAsmIsMissing = t;
+			AsmDetector.rootCause = t;
 			return data;
 		}
 	}