More explicit fix

Author: trask

agent/agent-tooling/src/main/java/com/microsoft/applicationinsights/agent/internal/classicsdk/ApplicationInsightsAppenderClassFileTransformer.java

@@ -27,6 +27,8 @@ public class ApplicationInsightsAppenderClassFileTransformer implements ClassFil
       UnshadedSdkPackageName.get() + "/log4j/v2/ApplicationInsightsAppender";
   private static final String UNSHADED_CLASS_NAME_LOG_4_JV_1_2 =
       UnshadedSdkPackageName.get() + "/log4j/v1_2/ApplicationInsightsAppender";
+  private static final String UNSHADED_CLASS_NAME_LOGBACK_LOGGING_EVENT =
+      UnshadedSdkPackageName.getLogbackPrefix() + "logback/classic/spi/ILoggingEvent";
 
   @Override
   @Nullable
@@ -72,10 +74,10 @@ public MethodVisitor visitMethod(
         @Nullable String signature,
         @Nullable String[] exceptions) {
       MethodVisitor mv = cw.visitMethod(access, name, descriptor, signature, exceptions);
-      // match append(SomeLoggingEvent): the descriptor type-strings are not checked here
-      // because Shadow relocates the "ch/qos/logback" literal, breaking the match at runtime;
-      // class-name filtering in transform() already guarantees we are in the right class
-      if (name.equals("append") && descriptor.startsWith("(L") && descriptor.endsWith(";)V")) {
+      if (name.equals("append")
+          && (descriptor.equals("(L" + UNSHADED_CLASS_NAME_LOGBACK_LOGGING_EVENT + ";)V")
+              || descriptor.equals("(Lorg/apache/log4j/spi/LoggingEvent;)V")
+              || descriptor.equals("(Lorg/apache/logging/log4j/core/LogEvent;)V"))) {
         // no-op the append() method
         mv.visitCode();
         mv.visitInsn(RETURN);

agent/agent-tooling/src/main/java/com/microsoft/applicationinsights/agent/internal/classicsdk/UnshadedSdkPackageName.java

@@ -5,16 +5,23 @@
 
 public class UnshadedSdkPackageName {
 
-  // using constant here so that it will NOT get shaded
-  // IMPORTANT FOR THIS NOT TO BE FINAL (or private)
-  // OTHERWISE COMPILER COULD THEORETICALLY INLINE IT BELOW AND APPLY .substring(1)
-  // and then it WOULD be shaded
+  // using package-prefix constants here so that they will NOT get shaded
+  // IMPORTANT FOR THESE NOT TO BE FINAL (or private)
+  // OTHERWISE COMPILER COULD THEORETICALLY INLINE THEM BELOW AND APPLY .substring(1)
+  // and then they WOULD be shaded
   @SuppressWarnings("ConstantField") // field value intentionally mutable for specific use case
   static String ALMOST_PREFIX = "!com/microsoft/applicationinsights";
 
+  @SuppressWarnings("ConstantField") // field value intentionally mutable for specific use case
+  static String ALMOST_LOGBACK_PREFIX = "!ch/qos/";
+
   public static String get() {
     return ALMOST_PREFIX.substring(1);
   }
 
+  public static String getLogbackPrefix() {
+    return ALMOST_LOGBACK_PREFIX.substring(1);
+  }
+
   private UnshadedSdkPackageName() {}
 }