[Dubbo-2.7.10] Fix `setSkyWalkingDynamicField(java.lang.Object) not found` #7517

zifeihan · 2021-04-07T14:54:16Z

What is the purpose of the change

Brief changelog

Verifying this change

Make sure there is a GitHub_issue field for the change (usually before you start working on it). Trivial changes like typos do not require a GitHub issue. Your pull request should address just this issue, without pulling in other changes - one PR resolves one issue.
Format the pull request title like [Dubbo-XXX] Fix UnknownException when host config not exist #XXX. Each commit in the pull request should have a meaningful subject line and body.
Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
Write necessary unit-test to verify your logic correction, more mock a little better when cross module dependency exist. If the new feature or significant change is committed, please remember to add sample in dubbo samples project.
Run mvn clean install -DskipTests=false & mvn clean test-compile failsafe:integration-test to make sure unit-test and integration-test pass.
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Fix setSkyWalkingDynamicField(java.lang.Object) not found,the comment is a detailed description, in order to avoid misunderstanding, sorry to use Chinese ,link issue, #2830

zifeihan · 2021-04-07T14:55:58Z

Dubbo+SkyWalking使用导致应用启动失败

1.现象：在10357启动启动失败，并包含部分和SkyWalking相关的日志，使用了SkyWalking可选插件包spring-annotation-plugin

Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'financeLessonServiceImpl': Unsatisfied dependency expressed through field 'lessonSynInfoService'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'lessonSynInfoServiceImpl' defined in URL [jar:file:/opt/10357/target.jar!/BOOT-INF/classes!/com/zhangmen/lesson/service/LessonSynInfoServiceImpl.class]: Initialization of bean failed; nested exception is java.lang.RuntimeException: [source error] setSkyWalkingDynamicField(java.lang.Object) not found in com.zhangmen.lesson.service.LessonSynInfoServiceImpl
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:586)
	at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:364)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1268)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:551)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:481)
	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:312)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:308)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:211)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1131)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1059)
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:583)
	... 27 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'lessonSynInfoServiceImpl' defined in URL [jar:file:/opt/10357/target.jar!/BOOT-INF/classes!/com/zhangmen/lesson/service/LessonSynInfoServiceImpl.class]: Initialization of bean failed; nested exception is java.lang.RuntimeException: [source error] setSkyWalkingDynamicField(java.lang.Object) not found in com.zhangmen.lesson.service.LessonSynInfoServiceImpl
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:562)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:481)
	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:312)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:308)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:211)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1131)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1059)
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:583)
	... 40 common frames omitted
Caused by: java.lang.RuntimeException: [source error] setSkyWalkingDynamicField(java.lang.Object) not found in com.zhangmen.lesson.service.LessonSynInfoServiceImpl
	at com.alibaba.dubbo.common.bytecode.ClassGenerator.toClass(ClassGenerator.java:354)
	at com.alibaba.dubbo.common.bytecode.ClassGenerator.toClass(ClassGenerator.java:293)
	at com.alibaba.dubbo.common.bytecode.Wrapper.makeWrapper(Wrapper.java:346)
	at com.alibaba.dubbo.common.bytecode.Wrapper.getWrapper(Wrapper.java:89)
	at com.alibaba.dubbo.rpc.proxy.javassist.JavassistProxyFactory.getInvoker(JavassistProxyFactory.java:40)
	at com.alibaba.dubbo.rpc.proxy.wrapper.StubProxyFactoryWrapper.getInvoker(StubProxyFactoryWrapper.java:104)
	at com.alibaba.dubbo.rpc.ProxyFactory$Adpative.getInvoker(ProxyFactory$Adpative.java)
	at com.alibaba.dubbo.config.ServiceConfig.exportLocal(ServiceConfig.java:515)
	at com.alibaba.dubbo.config.ServiceConfig.doExportUrlsFor1Protocol(ServiceConfig.java:469)
	at com.alibaba.dubbo.config.ServiceConfig.doExportUrls(ServiceConfig.java:285)
	at com.alibaba.dubbo.config.ServiceConfig.doExport(ServiceConfig.java:246)
	at com.alibaba.dubbo.config.ServiceConfig.export(ServiceConfig.java:145)
	at com.alibaba.dubbo.config.spring.AnnotationBean.postProcessAfterInitialization(AnnotationBean.java:202)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsAfterInitialization(AbstractAutowireCapableBeanFactory.java:421)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1634)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553)
	... 49 common frames omitted
Caused by: javassist.CannotCompileException: [source error] setSkyWalkingDynamicField(java.lang.Object) not found in com.zhangmen.lesson.service.LessonSynInfoServiceImpl
	at javassist.CtNewMethod.make(CtNewMethod.java:79)
	at javassist.CtNewMethod.make(CtNewMethod.java:45)
	at com.alibaba.dubbo.common.bytecode.ClassGenerator.toClass(ClassGenerator.java:322)
	... 64 common frames omitted
Caused by: javassist.compiler.CompileError: setSkyWalkingDynamicField(java.lang.Object) not found in com.zhangmen.lesson.service.LessonSynInfoServiceImpl
	at javassist.compiler.TypeChecker.atMethodCallCore(TypeChecker.java:749)
	at javassist.compiler.TypeChecker.atCallExpr(TypeChecker.java:695)
	at javassist.compiler.JvstTypeChecker.atCallExpr(JvstTypeChecker.java:157)
	at javassist.compiler.ast.CallExpr.accept(CallExpr.java:46)
	at javassist.compiler.CodeGen.doTypeCheck(CodeGen.java:242)
	at javassist.compiler.CodeGen.atStmnt(CodeGen.java:330)
	at javassist.compiler.ast.Stmnt.accept(Stmnt.java:50)
	at javassist.compiler.CodeGen.atStmnt(CodeGen.java:351)
	at javassist.compiler.ast.Stmnt.accept(Stmnt.java:50)
	at javassist.compiler.CodeGen.atIfStmnt(CodeGen.java:398)
	at javassist.compiler.CodeGen.atStmnt(CodeGen.java:355)
	at javassist.compiler.ast.Stmnt.accept(Stmnt.java:50)
	at javassist.compiler.CodeGen.atStmnt(CodeGen.java:351)
	at javassist.compiler.ast.Stmnt.accept(Stmnt.java:50)
	at javassist.compiler.CodeGen.atMethodBody(CodeGen.java:292)
	at javassist.compiler.CodeGen.atMethodDecl(CodeGen.java:274)
	at javassist.compiler.ast.MethodDecl.accept(MethodDecl.java:44)
	at javassist.compiler.Javac.compileMethod(Javac.java:169)
	at javassist.compiler.Javac.compile(Javac.java:95)
	at javassist.CtNewMethod.make(CtNewMethod.java:74)
	... 66 common frames omitted
609902 [DubboShutdownHook] INFO  c.a.dubbo.config.AbstractConfig -  [DUBBO] Run shutdown hook now., dubbo version: 2.8.4-SNAPSHOT, current host: 127.0.0.1
609910 [DubboShutdownHook] INFO  c.a.d.r.s.AbstractRegistryFactory -  [DUBBO] Close all registries [zookeeper://vpc-fat-2.zmaxis.com:2181/com.alibaba.dubbo.registry.RegistryService?application=lesson-service&client=curator&dubbo=2.8.4-SNAPSHOT&interface=com.alibaba.dubbo.registry.RegistryService&organization=zhangmen.com&owner=platform&pid=31067&timestamp=1617781930060], dubbo version: 2.8.4-SNAPSHOT, current host: 127.0.0.1

2.原因排查

排查该问题我们需要先明确几点：

2.1 SkyWalking在增强某个类的成员方法时（非静态方法），会为修改该类字节码，会为其增加_$EnhancedClassField_ws字段，见代码1，并使其实现org.apache.skywalking.apm.agent.core.plugin.interceptor.enhance.EnhancedInstance接口，该接口中存在两个方法，见代码2。

代码1： 
 				/**
         * Manipulate class source code.<br/>
         *
         * new class need:<br/>
         * 1.Add field, name {@link #CONTEXT_ATTR_NAME}.
         * 2.Add a field accessor for this field.
         *
         * And make sure the source codes manipulation only occurs once.
         *
         */
        if (!typeDescription.isAssignableTo(EnhancedInstance.class)) {
            if (!context.isObjectExtended()) {
                newClassBuilder = newClassBuilder.defineField(
                    CONTEXT_ATTR_NAME, Object.class, ACC_PRIVATE | ACC_VOLATILE)
                                                 .implement(EnhancedInstance.class)
                                                 .intercept(FieldAccessor.ofField(CONTEXT_ATTR_NAME));
                context.extendObjectCompleted();
            }
        }

代码2：
package org.apache.skywalking.apm.agent.core.plugin.interceptor.enhance;

public interface EnhancedInstance {
    Object getSkyWalkingDynamicField();

    void setSkyWalkingDynamicField(Object value);
}

2.2 当某个类被SkyWalking增强后，可以通过反射机制查看到SkyWalking为其增加的getSkyWalkingDynamicField()，setSkyWalkingDynamicField这两个方法。还有就有就是如果没有使用javaagent相关机制，没有办法获取到jvm中被其他agent增强后的字节码，简单来说没有特殊机制没有办法获取到被增强后的字节码（或许有，我还不知道相关的办法）。

有了上述两点支撑，对于接下来排查问题就比较方便了。

2.3 问题发生的原因，我们可以看到在异常中存在setSkyWalkingDynamicField(java.lang.Object) not found in com.zhangmen.lesson.service.LessonSynInfoServiceImpl这个信息，当我看到这个信息的时候，我有两个怀疑点，1. 为什么dubbo的代码代理了setSkyWalkingDynamicField(java.lang.Object) 这个方法，2. com.zhangmen.lesson.service.LessonSynInfoServiceImpl这个类在加载完成后，里面肯定是存在setSkyWalkingDynamicField(java.lang.Object) 这个方法，为什么dubbo字节码代理的时候却说没有找到该方法。接下来我看了一下dubbo（2.8.4-SNAPSHOT）生成代理的代码如下，为了方便分析问题，添加了部分注释。

com.alibaba.dubbo.common.bytecode.Wrapper#makeWrapper:    
    private static Wrapper makeWrapper(Class<?> c) {
        if (c.isPrimitive()) {
            throw new IllegalArgumentException("Can not create wrapper for primitive type: " + c);
        } else {
            String name = c.getName();
            ClassLoader cl = ClassHelper.getClassLoader(c);
            StringBuilder c1 = new StringBuilder("public void setPropertyValue(Object o, String n, Object v){ ");
            StringBuilder c2 = new StringBuilder("public Object getPropertyValue(Object o, String n){ ");
            StringBuilder c3 = new StringBuilder("public Object invokeMethod(Object o, String n, Class[] p, Object[] v) throws " + InvocationTargetException.class.getName() + "{ ");
            c1.append(name).append(" w; try{ w = ((").append(name).append(")$1); }catch(Throwable e){ throw new IllegalArgumentException(e); }");
            c2.append(name).append(" w; try{ w = ((").append(name).append(")$1); }catch(Throwable e){ throw new IllegalArgumentException(e); }");
            c3.append(name).append(" w; try{ w = ((").append(name).append(")$1); }catch(Throwable e){ throw new IllegalArgumentException(e); }");
            Map<String, Class<?>> pts = new HashMap();
            Map<String, Method> ms = new LinkedHashMap();
            List<String> mns = new ArrayList();
            List<String> dmns = new ArrayList();
            Field[] arr$ = c.getFields();
            int len$ = arr$.length;

            for(int i$ = 0; i$ < len$; ++i$) {
                Field f = arr$[i$];
                String fn = f.getName();
                Class<?> ft = f.getType();
                if (!Modifier.isStatic(f.getModifiers()) && !Modifier.isTransient(f.getModifiers())) {
                    c1.append(" if( $2.equals(\"").append(fn).append("\") ){ w.").append(fn).append("=").append(arg(ft, "$3")).append("; return; }");
                    c2.append(" if( $2.equals(\"").append(fn).append("\") ){ return ($w)w.").append(fn).append("; }");
                    pts.put(fn, ft);
                }
            }

						// 在这里使用了反射获取当前类的方法，这里返回的方法中肯定包含SkyWalking字节码增强添加的两个方法
            Method[] methods = c.getMethods();
            boolean hasMethod = hasMethods(methods);
            if (hasMethod) {
                c3.append(" try{");
            }

            Method[] arr$ = methods;
            int len$ = methods.length;

            int ix;
            for(int i$ = 0; i$ < len$; ++i$) {
                Method m = arr$[i$];
                if (m.getDeclaringClass() != Object.class) {
                    String mn = m.getName();
                    c3.append(" if( \"").append(mn).append("\".equals( $2 ) ");
                    ix = m.getParameterTypes().length;
                    c3.append(" && ").append(" $3.length == ").append(ix);
                    boolean override = false;
                    Method[] arr$ = methods;
                    int len$ = methods.length;

                    for(int i$ = 0; i$ < len$; ++i$) {
                        Method m2 = arr$[i$];
                        if (m != m2 && m.getName().equals(m2.getName())) {
                            override = true;
                            break;
                        }
                    }

                    if (override && ix > 0) {
                        for(int l = 0; l < ix; ++l) {
                            c3.append(" && ").append(" $3[").append(l).append("].getName().equals(\"").append(m.getParameterTypes()[l].getName()).append("\")");
                        }
                    }

                    c3.append(" ) { ");
                    if (m.getReturnType() == Void.TYPE) {
                        c3.append(" w.").append(mn).append('(').append(args(m.getParameterTypes(), "$4")).append(");").append(" return null;");
                    } else {
                        c3.append(" return ($w)w.").append(mn).append('(').append(args(m.getParameterTypes(), "$4")).append(");");
                    }

                    c3.append(" }");
                    mns.add(mn);
                    if (m.getDeclaringClass() == c) {
                        dmns.add(mn);
                    }

                    ms.put(ReflectUtils.getDesc(m), m);
                }
            }

            if (hasMethod) {
                c3.append(" } catch(Throwable e) { ");
                c3.append("     throw new java.lang.reflect.InvocationTargetException(e); ");
                c3.append(" }");
            }

            c3.append(" throw new " + NoSuchMethodException.class.getName() + "(\"Not found method \\\"\"+$2+\"\\\" in class " + c.getName() + ".\"); }");
            Iterator i$ = ms.entrySet().iterator();

            while(i$.hasNext()) {
                Entry<String, Method> entry = (Entry)i$.next();
                String md = (String)entry.getKey();
                Method method = (Method)entry.getValue();
                Matcher matcher;
                String pn;
                if ((matcher = ReflectUtils.GETTER_METHOD_DESC_PATTERN.matcher(md)).matches()) {
                    pn = propertyName(matcher.group(1));
                    c2.append(" if( $2.equals(\"").append(pn).append("\") ){ return ($w)w.").append(method.getName()).append("(); }");
                    pts.put(pn, method.getReturnType());
                } else if ((matcher = ReflectUtils.IS_HAS_CAN_METHOD_DESC_PATTERN.matcher(md)).matches()) {
                    pn = propertyName(matcher.group(1));
                    c2.append(" if( $2.equals(\"").append(pn).append("\") ){ return ($w)w.").append(method.getName()).append("(); }");
                    pts.put(pn, method.getReturnType());
                } else if ((matcher = ReflectUtils.SETTER_METHOD_DESC_PATTERN.matcher(md)).matches()) {
                    Class<?> pt = method.getParameterTypes()[0];
                    String pn = propertyName(matcher.group(1));
                    c1.append(" if( $2.equals(\"").append(pn).append("\") ){ w.").append(method.getName()).append("(").append(arg(pt, "$3")).append("); return; }");
                    pts.put(pn, pt);
                }
            }

            c1.append(" throw new " + NoSuchPropertyException.class.getName() + "(\"Not found property \\\"\"+$2+\"\\\" filed or setter method in class " + c.getName() + ".\"); }");
            c2.append(" throw new " + NoSuchPropertyException.class.getName() + "(\"Not found property \\\"\"+$2+\"\\\" filed or setter method in class " + c.getName() + ".\"); }");
            long id = WRAPPER_CLASS_COUNTER.getAndIncrement();
            ClassGenerator cc = ClassGenerator.newInstance(cl);
            cc.setClassName((Modifier.isPublic(c.getModifiers()) ? Wrapper.class.getName() : c.getName() + "$sw") + id);
            cc.setSuperClass(Wrapper.class);
            cc.addDefaultConstructor();
            cc.addField("public static String[] pns;");
            cc.addField("public static " + Map.class.getName() + " pts;");
            cc.addField("public static String[] mns;");
            cc.addField("public static String[] dmns;");
            int i = 0;

            for(ix = ms.size(); i < ix; ++i) {
                cc.addField("public static Class[] mts" + i + ";");
            }

            cc.addMethod("public String[] getPropertyNames(){ return pns; }");
            cc.addMethod("public boolean hasProperty(String n){ return pts.containsKey($1); }");
            cc.addMethod("public Class getPropertyType(String n){ return (Class)pts.get($1); }");
            cc.addMethod("public String[] getMethodNames(){ return mns; }");
            cc.addMethod("public String[] getDeclaredMethodNames(){ return dmns; }");
            cc.addMethod(c1.toString());
            cc.addMethod(c2.toString());
            cc.addMethod(c3.toString());

            try {
            		// 代理生成类，dubbo自身的动态代理，在此步骤将会发生异常
                Class<?> wc = cc.toClass();
                wc.getField("pts").set((Object)null, pts);
                wc.getField("pns").set((Object)null, pts.keySet().toArray(new String[0]));
                wc.getField("mns").set((Object)null, mns.toArray(new String[0]));
                wc.getField("dmns").set((Object)null, dmns.toArray(new String[0]));
                ix = 0;
                Iterator i$ = ms.values().iterator();

                while(i$.hasNext()) {
                    Method m = (Method)i$.next();
                    wc.getField("mts" + ix++).set((Object)null, m.getParameterTypes());
                }

                Wrapper var50 = (Wrapper)wc.newInstance();
                return var50;
            } catch (RuntimeException var27) {
                throw var27;
            } catch (Throwable var28) {
                throw new RuntimeException(var28.getMessage(), var28);
            } finally {
                cc.release();
                ms.clear();
                mns.clear();
                dmns.clear();
            }
        }
    }

2.4 dubbo自身使用javassist来生成相关的动态类，用来代理真实的方法，我们定位到异常栈发生异常的方法，接下来我们主要关注targetClass从那里获取的，并且为什么没有setSkyWalkingDynamicField(java.lang.Object) 这个方法。

javassist.compiler.TypeChecker#atMethodCallCore:
	public Method atMethodCallCore(CtClass targetClass, String mname, ASTList args) throws CompileError {
        int nargs = this.getMethodArgsLength(args);
        int[] types = new int[nargs];
        int[] dims = new int[nargs];
        String[] cnames = new String[nargs];
        this.atMethodArgs(args, types, dims, cnames);
        Method found = this.resolver.lookupMethod(targetClass, this.thisClass, this.thisMethod, mname, types, dims, cnames);
        String clazz;
        if (found == null) {
            clazz = targetClass.getName();
            String signature = argTypesToString(types, dims, cnames);
            String msg;
            if (mname.equals("<init>")) {
                msg = "cannot find constructor " + clazz + signature;
            } else {
                msg = mname + signature + " not found in " + clazz;
            }

            throw new CompileError(msg);
        } else {
            clazz = found.info.getDescriptor();
            this.setReturnType(clazz);
            return found;
        }
    }

lookupMethod相关逻辑如下，可以看到是通过解析classFile来实现的：

private MemberResolver.Method lookupMethod(CtClass clazz, String methodName, int[] argTypes, int[] argDims, String[] argClassNames, boolean onlyExact) throws CompileError {
        MemberResolver.Method maybe = null;
        ClassFile cf = clazz.getClassFile2();
        int i;
        MemberResolver.Method r;
        if (cf != null) {
            List list = cf.getMethods();
            int n = list.size();

            for(int i = 0; i < n; ++i) {
                MethodInfo minfo = (MethodInfo)list.get(i);
                if (minfo.getName().equals(methodName) && (minfo.getAccessFlags() & 64) == 0) {
                    i = this.compareSignature(minfo.getDescriptor(), argTypes, argDims, argClassNames);
                    if (i != -1) {
                        r = new MemberResolver.Method(clazz, minfo, i);
                        if (i == 0) {
                            return r;
                        }

                        if (maybe == null || maybe.notmatch > i) {
                            maybe = r;
                        }
                    }
                }
            }
        }

        if (onlyExact) {
            maybe = null;
        } else if (maybe != null) {
            return maybe;
        }

        int mod = clazz.getModifiers();
        boolean isIntf = Modifier.isInterface(mod);

        try {
            if (!isIntf) {
                CtClass pclazz = clazz.getSuperclass();
                if (pclazz != null) {
                    MemberResolver.Method r = this.lookupMethod(pclazz, methodName, argTypes, argDims, argClassNames, onlyExact);
                    if (r != null) {
                        return r;
                    }
                }
            }
        } catch (NotFoundException var15) {
        }

        try {
            CtClass[] ifs = clazz.getInterfaces();
            int size = ifs.length;

            for(i = 0; i < size; ++i) {
                r = this.lookupMethod(ifs[i], methodName, argTypes, argDims, argClassNames, onlyExact);
                if (r != null) {
                    return r;
                }
            }

            if (isIntf) {
                CtClass pclazz = clazz.getSuperclass();
                if (pclazz != null) {
                    r = this.lookupMethod(pclazz, methodName, argTypes, argDims, argClassNames, onlyExact);
                    if (r != null) {
                        return r;
                    }
                }
            }
        } catch (NotFoundException var16) {
        }

        return maybe;
    }

于是我们把定位targetClass，转换为了classfile从何而来，最终定位到targetClass来源于javassist.ClassPool#createCtClass，，在创建CtClass时调用了如下构造函数，但是这里面的classfile并没有被赋值，但是在该类的父类中存在getClassFile方法，并在该方法中返回this.getClassFile2()，通过getClassFile2()相关的逻辑我们知道了classfile最终来源于读取了classpath下的类源码文件，而在该源码中肯定是不存在和SkyWalking相关的代码。

javassist.CtClassType:
	CtClassType(String name, ClassPool cp) {
        super(name);
        this.doPruning = ClassPool.doPruning;
        this.classPool = cp;
        this.wasChanged = this.wasFrozen = this.wasPruned = this.gcConstPool = false;
        this.classfile = null;
        this.rawClassfile = null;
        this.memberCache = null;
        this.accessors = null;
        this.fieldInitializers = null;
        this.hiddenMethods = null;
        this.uniqueNumberSeed = 0;
        this.getCount = 0;
    }
    
    public ClassFile getClassFile2() {
        return this.getClassFile3(true);
    }

    public ClassFile getClassFile3(boolean doCompress) {
        ClassFile cfile = this.classfile;
        if (cfile != null) {
            return cfile;
        } else {
            if (doCompress) {
                this.classPool.compress();
            }

            if (this.rawClassfile != null) {
                try {
                    ClassFile cf = new ClassFile(new DataInputStream(new ByteArrayInputStream(this.rawClassfile)));
                    this.rawClassfile = null;
                    this.getCount = 2;
                    return this.setClassFile(cf);
                } catch (IOException var16) {
                    throw new RuntimeException(var16.toString(), var16);
                }
            } else {
                Object fin = null;

                ClassFile var5;
                try {
                    fin = this.classPool.openClassfile(this.getName());
                    if (fin == null) {
                        throw new NotFoundException(this.getName());
                    }

                    fin = new BufferedInputStream((InputStream)fin);
                    ClassFile cf = new ClassFile(new DataInputStream((InputStream)fin));
                    if (!cf.getName().equals(this.qualifiedName)) {
                        throw new RuntimeException("cannot find " + this.qualifiedName + ": " + cf.getName() + " found in " + this.qualifiedName.replace('.', '/') + ".class");
                    }

                    var5 = this.setClassFile(cf);
                } catch (NotFoundException var17) {
                    throw new RuntimeException(var17.toString(), var17);
                } catch (IOException var18) {
                    throw new RuntimeException(var18.toString(), var18);
                } finally {
                    if (fin != null) {
                        try {
                            ((InputStream)fin).close();
                        } catch (IOException var15) {
                        }
                    }

                }

                return var5;
            }
        }
    }

问题解决：

Dubbo这种在代理时通过反射获取方法然后在生成类时的逻辑有些问题，在反射时获取的方法有可能是增强后的，有可能多添加方法，但是在生成类时却获取了原字节码文件中的方法，导致javassist生成类时字节码校验失败。

修复办法：

1.修改dubbo源码com.alibaba.dubbo.common.bytecode.Wrapper#makeWrapper逻辑，在通过javassist获取源文件中的方法，和最终的生成、校验逻辑一致。

2.其他办法暂时还没有...

codecov-io · 2021-04-08T03:20:31Z

Codecov Report

Merging #7517 (322d072) into master (6055932) will decrease coverage by 0.38%.
The diff coverage is 84.61%.

@@             Coverage Diff              @@
##             master    #7517      +/-   ##
============================================
- Coverage     59.24%   58.86%   -0.39%     
+ Complexity      503      500       -3     
============================================
  Files          1079     1079              
  Lines         43385    43350      -35     
  Branches       6329     6297      -32     
============================================
- Hits          25704    25516     -188     
- Misses        14842    14989     +147     
- Partials       2839     2845       +6

Impacted Files	Coverage Δ	Complexity Δ
...java/org/apache/dubbo/common/bytecode/Wrapper.java	`82.58% <84.61%> (+0.04%)`	`0.00 <0.00> (ø)`
...a/org/apache/dubbo/rpc/filter/AccessLogFilter.java	`26.86% <0.00%> (-52.24%)`	`0.00% <0.00%> (ø%)`
...va/org/apache/dubbo/rpc/support/AccessLogData.java	`53.16% <0.00%> (-37.98%)`	`0.00% <0.00%> (ø%)`
...ng/transport/dispatcher/all/AllChannelHandler.java	`62.06% <0.00%> (-34.49%)`	`0.00% <0.00%> (ø%)`
...bbo/common/bytecode/CustomizedLoaderClassPath.java	`28.00% <0.00%> (-16.00%)`	`0.00% <0.00%> (ø%)`
...rg/apache/dubbo/remoting/utils/PayloadDropper.java	`76.92% <0.00%> (-15.39%)`	`0.00% <0.00%> (ø%)`
...ng/transport/dispatcher/WrappedChannelHandler.java	`47.82% <0.00%> (-15.22%)`	`0.00% <0.00%> (ø%)`
...bo/rpc/cluster/support/FailbackClusterInvoker.java	`52.45% <0.00%> (-14.76%)`	`0.00% <0.00%> (ø%)`
.../remoting/transport/netty4/NettyClientHandler.java	`72.88% <0.00%> (-13.56%)`	`0.00% <0.00%> (ø%)`
...dubbo/common/status/support/LoadStatusChecker.java	`50.00% <0.00%> (-11.54%)`	`0.00% <0.00%> (ø%)`
... and 48 more

Continue to review full report at Codecov.

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Powered by Codecov. Last update 6055932...322d072. Read the comment docs.

…ound` (apache#7517) * Fix `setSkyWalkingDynamicField(java.lang.Object) not found` * Polishing. * Polishing. * Polishing.

Fix setSkyWalkingDynamicField(java.lang.Object) not found

8c375d1

zifeihan changed the title ~~[Dubbo-2.7.10-SNAPSHOT] Fix setSkyWalkingDynamicField(java.lang.Object) not found~~ [Dubbo-2.7.10] Fix setSkyWalkingDynamicField(java.lang.Object) not found Apr 7, 2021

zifeihan mentioned this pull request Apr 7, 2021

javassist.compiler.CompileError: setSkyWalkingDynamicField(java.lang.Object) apache/skywalking#3996

Closed

4 tasks

zifeihan added 3 commits April 8, 2021 10:45

Polishing.

5b7feb4

Polishing.

322d072

Polishing.

593871c

kimmking approved these changes Apr 27, 2021

View reviewed changes

kimmking merged commit 68062c1 into apache:master Apr 27, 2021

AlbumenJ added a commit to AlbumenJ/dubbo that referenced this pull request May 28, 2021

Pick from apache#7517 68062c1

7325f47

AlbumenJ mentioned this pull request Sep 12, 2023

Fix ClassPool issue when multi-classloader #13015

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[Dubbo-2.7.10] Fix `setSkyWalkingDynamicField(java.lang.Object) not found` #7517

[Dubbo-2.7.10] Fix `setSkyWalkingDynamicField(java.lang.Object) not found` #7517

zifeihan commented Apr 7, 2021 •

edited

zifeihan commented Apr 7, 2021

codecov-io commented Apr 8, 2021 •

edited

[Dubbo-2.7.10] Fix setSkyWalkingDynamicField(java.lang.Object) not found #7517

[Dubbo-2.7.10] Fix setSkyWalkingDynamicField(java.lang.Object) not found #7517

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zifeihan commented Apr 7, 2021 • edited

What is the purpose of the change

Brief changelog

Verifying this change

zifeihan commented Apr 7, 2021

Dubbo+SkyWalking使用导致应用启动失败

codecov-io commented Apr 8, 2021 • edited

Codecov Report

[Dubbo-2.7.10] Fix `setSkyWalkingDynamicField(java.lang.Object) not found` #7517

[Dubbo-2.7.10] Fix `setSkyWalkingDynamicField(java.lang.Object) not found` #7517

zifeihan commented Apr 7, 2021 •

edited

codecov-io commented Apr 8, 2021 •

edited