Remove muzzle dead code, doc cleanup, and better logging

buildSrc/src/main/groovy/MuzzlePlugin.groovy

@@ -4,7 +4,7 @@ import org.gradle.api.Project
 import java.lang.reflect.Method
 
 /**
- * POC muzzle task plugin which runs muzzle validation against an instrumentation's compile-time dependencies.
+ * muzzle task plugin which runs muzzle validation against an instrumentation's compile-time dependencies.
  *
  * <p/>TODO: merge this with version scan
  */

dd-java-agent/agent-tooling/src/main/java/datadog/trace/agent/tooling/Instrumenter.java

@@ -90,15 +90,16 @@ public interface Instrumenter {
                         JavaModule module,
                         Class<?> classBeingRedefined,
                         ProtectionDomain protectionDomain) {
-                      // Optimization: calling getMuzzleReferenceMatcher() inside this method prevents unnecessary loading of muzzle references during agentBuilder setup.
+                      // Optimization: calling getInstrumentationMuzzle() inside this method prevents unnecessary loading of muzzle references during agentBuilder setup.
                       final ReferenceMatcher muzzle = getInstrumentationMuzzle();
                       if (null != muzzle) {
                         List<Reference.Mismatch> mismatches =
                             muzzle.getMismatchedReferenceSources(classLoader);
                         if (mismatches.size() > 0) {
                           log.debug(
-                              "Instrumentation muzzled: {} on {}",
+                              "Instrumentation muzzled: {} -- {} on {}",
                               instrumentationPrimaryName,
+                              this.getClass().getName(),
                               classLoader);
                         }
                         for (Reference.Mismatch mismatch : mismatches) {
@@ -149,6 +150,8 @@ public interface Instrumenter {
       return getConfigEnabled("dd.integrations.enabled", true);
     }
 
+    // TODO: move common config helpers to Utils
+
     public static String getPropOrEnv(final String name) {
       return System.getProperty(name, System.getenv(propToEnvName(name)));
     }

dd-java-agent/agent-tooling/src/main/java/datadog/trace/agent/tooling/muzzle/MuzzleGradlePlugin.java

@@ -1,19 +1,10 @@
 package datadog.trace.agent.tooling.muzzle;
 
 import datadog.trace.agent.tooling.Instrumenter;
-import net.bytebuddy.asm.AsmVisitorWrapper;
 import net.bytebuddy.build.Plugin;
-import net.bytebuddy.description.field.FieldDescription;
-import net.bytebuddy.description.field.FieldList;
-import net.bytebuddy.description.method.MethodList;
 import net.bytebuddy.description.type.TypeDefinition;
 import net.bytebuddy.description.type.TypeDescription;
 import net.bytebuddy.dynamic.DynamicType.Builder;
-import net.bytebuddy.implementation.Implementation;
-import net.bytebuddy.jar.asm.ClassVisitor;
-import net.bytebuddy.jar.asm.MethodVisitor;
-import net.bytebuddy.jar.asm.Opcodes;
-import net.bytebuddy.pool.TypePool;
 
 /** Bytebuddy gradle plugin which creates muzzle-references at compile time. */
 public class MuzzleGradlePlugin implements Plugin {
@@ -52,58 +43,4 @@ public class MuzzleGradlePlugin implements Plugin {
       return builder;
     }
   }
-
-  private static class RemoveFinalFlagVisitor implements AsmVisitorWrapper {
-    final String methodName;
-
-    public RemoveFinalFlagVisitor(String methodName) {
-      this.methodName = methodName;
-    }
-
-    @Override
-    public int mergeWriter(int flags) {
-      return flags;
-    }
-
-    @Override
-    public int mergeReader(int flags) {
-      return flags;
-    }
-
-    @Override
-    public ClassVisitor wrap(
-        TypeDescription instrumentedType,
-        ClassVisitor classVisitor,
-        Implementation.Context implementationContext,
-        TypePool typePool,
-        FieldList<FieldDescription.InDefinedShape> fields,
-        MethodList<?> methods,
-        int writerFlags,
-        int readerFlags) {
-      return new Visitor(classVisitor);
-    }
-
-    private class Visitor extends ClassVisitor {
-      public Visitor(ClassVisitor cv) {
-        super(Opcodes.ASM6, cv);
-      }
-
-      @Override
-      public MethodVisitor visitMethod(
-          final int access,
-          final String name,
-          final String descriptor,
-          final String signature,
-          final String[] exceptions) {
-        MethodVisitor methodVisitor =
-            super.visitMethod(access, name, descriptor, signature, exceptions);
-        if (name.equals(methodName) && (access & Opcodes.ACC_FINAL) != 0) {
-          return super.visitMethod(
-              access ^ Opcodes.ACC_FINAL, name, descriptor, signature, exceptions);
-        } else {
-          return super.visitMethod(access, name, descriptor, signature, exceptions);
-        }
-      }
-    }
-  }
 }

dd-java-agent/instrumentation/apache-httpclient-4.3/src/main/java/datadog/trace/instrumentation/apachehttpclient/ApacheHttpClientInstrumentation.java

@@ -45,7 +45,7 @@ public class ApacheHttpClientInstrumentation extends Instrumenter.Default {
   public String[] helperClassNames() {
     return new String[] {
       "datadog.trace.instrumentation.apachehttpclient.DDTracingClientExec",
-      "datadog.trace.instrumentation.apachehttpclient.DDTracingClientExec$HttpHeadersInjectAdapter",
+      "datadog.trace.instrumentation.apachehttpclient.DDTracingClientExec$HttpHeadersInjectAdapter"
     };
   }