GIT_BRANCH variable is not populated in jenkins pipeline

stages {
   stage('checkout') {
       steps {
            git credentialsId: 'jenkins', 
                url: 'git@git.xxx.com:jianjing/jenkinspipeline.git',
                branch: "test" 
        }
    }

    stage('test') {
        steps {
            sh "echo $\{GIT_BRANCH}"
        }
    }

 
groovy.lang.MissingPropertyException: No such property: GIT_BRANCH for class: groovy.lang.Binding
	at groovy.lang.Binding.getVariable(Binding.java:63)
	at org.jenkinsci.plugins.scriptsecurity.sandbox.groovy.SandboxInterceptor.onGetProperty(SandboxInterceptor.java:232)
	at org.kohsuke.groovy.sandbox.impl.Checker$5.call(Checker.java:255)
	at org.kohsuke.groovy.sandbox.impl.Checker.checkedGetProperty(Checker.java:259)
	at org.kohsuke.groovy.sandbox.impl.Checker.checkedGetProperty(Checker.java:235)
	at org.kohsuke.groovy.sandbox.impl.Checker.checkedGetProperty(Checker.java:235)
	at org.kohsuke.groovy.sandbox.impl.Checker.checkedGetProperty(Checker.java:235)
	at org.kohsuke.groovy.sandbox.impl.Checker.checkedGetProperty(Checker.java:235)
	at com.cloudbees.groovy.cps.sandbox.SandboxInvoker.getProperty(SandboxInvoker.java:28)
	at com.cloudbees.groovy.cps.impl.PropertyAccessBlock.rawGet(PropertyAccessBlock.java:20)
	at WorkflowScript.run(WorkflowScript:19)
	at org.jenkinsci.plugins.pipeline.modeldefinition.ModelInterpreter.delegateAndExecute(jar:file:/data/program/jenkins/plugins/pipeline-model-definition/WEB-INF/lib/pipeline-model-definition.jar!/org/jenkinsci/plugins/pipeline/modeldefinition/ModelInterpreter.groovy:172)
	at org.jenkinsci.plugins.pipeline.modeldefinition.ModelInterpreter.executeSingleStage(jar:file:/data/program/jenkins/plugins/pipeline-model-definition/WEB-INF/lib/pipeline-model-definition.jar!/org/jenkinsci/plugins/pipeline/modeldefinition/ModelInterpreter.groovy:438)
	at org.jenkinsci.plugins.pipeline.modeldefinition.ModelInterpreter.catchRequiredContextForNode(jar:file:/data/program/jenkins/plugins/pipeline-model-definition/WEB-INF/lib/pipeline-model-definition.jar!/org/jenkinsci/plugins/pipeline/modeldefinition/ModelInterpreter.groovy:188)
	at org.jenkinsci.plugins.pipeline.modeldefinition.ModelInterpreter.catchRequiredContextForNode(jar:file:/data/program/jenkins/plugins/pipeline-model-definition/WEB-INF/lib/pipeline-model-definition.jar!/org/jenkinsci/plugins/pipeline/modeldefinition/ModelInterpreter.groovy:186)
	at org.jenkinsci.plugins.pipeline.modeldefinition.ModelInterpreter.executeSingleStage(jar:file:/data/program/jenkins/plugins/pipeline-model-definition/WEB-INF/lib/pipeline-model-definition.jar!/org/jenkinsci/plugins/pipeline/modeldefinition/ModelInterpreter.groovy:437)
	at org.jenkinsci.plugins.pipeline.modeldefinition.ModelInterpreter.call(jar:file:/data/program/jenkins/plugins/pipeline-model-definition/WEB-INF/lib/pipeline-model-definition.jar!/org/jenkinsci/plugins/pipeline/modeldefinition/ModelInterpreter.groovy:101)
	at org.jenkinsci.plugins.pipeline.modeldefinition.ModelInterpreter.toolsBlock(jar:file:/data/program/jenkins/plugins/pipeline-model-definition/WEB-INF/lib/pipeline-model-definition.jar!/org/jenkinsci/plugins/pipeline/modeldefinition/ModelInterpreter.groovy:337)
	at org.jenkinsci.plugins.pipeline.modeldefinition.ModelInterpreter.toolsBlock(jar:file:/data/program/jenkins/plugins/pipeline-model-definition/WEB-INF/lib/pipeline-model-definition.jar!/org/jenkinsci/plugins/pipeline/modeldefinition/ModelInterpreter.groovy:336)
	at org.jenkinsci.plugins.pipeline.modeldefinition.ModelInterpreter.call(jar:file:/data/program/jenkins/plugins/pipeline-model-definition/WEB-INF/lib/pipeline-model-definition.jar!/org/jenkinsci/plugins/pipeline/modeldefinition/ModelInterpreter.groovy:99)
	at org.jenkinsci.plugins.pipeline.modeldefinition.ModelInterpreter.withEnvBlock(jar:file:/data/program/jenkins/plugins/pipeline-model-definition/WEB-INF/lib/pipeline-model-definition.jar!/org/jenkinsci/plugins/pipeline/modeldefinition/ModelInterpreter.groovy:230)
	at org.jenkinsci.plugins.pipeline.modeldefinition.ModelInterpreter.withEnvBlock(jar:file:/data/program/jenkins/plugins/pipeline-model-definition/WEB-INF/lib/pipeline-model-definition.jar!/org/jenkinsci/plugins/pipeline/modeldefinition/ModelInterpreter.groovy:229)
	at org.jenkinsci.plugins.pipeline.modeldefinition.ModelInterpreter.call(jar:file:/data/program/jenkins/plugins/pipeline-model-definition/WEB-INF/lib/pipeline-model-definition.jar!/org/jenkinsci/plugins/pipeline/modeldefinition/ModelInterpreter.groovy:98)
	at org.jenkinsci.plugins.pipeline.modeldefinition.ModelInterpreter.withCredentialsBlock(jar:file:/data/program/jenkins/plugins/pipeline-model-definition/WEB-INF/lib/pipeline-model-definition.jar!/org/jenkinsci/plugins/pipeline/modeldefinition/ModelInterpreter.groovy:267)
	at org.jenkinsci.plugins.pipeline.modeldefinition.ModelInterpreter.withCredentialsBlock(jar:file:/data/program/jenkins/plugins/pipeline-model-definition/WEB-INF/lib/pipeline-model-definition.jar!/org/jenkinsci/plugins/pipeline/modeldefinition/ModelInterpreter.groovy:266)
	at org.jenkinsci.plugins.pipeline.modeldefinition.ModelInterpreter.call(jar:file:/data/program/jenkins/plugins/pipeline-model-definition/WEB-INF/lib/pipeline-model-definition.jar!/org/jenkinsci/plugins/pipeline/modeldefinition/ModelInterpreter.groovy:97)
	at org.jenkinsci.plugins.pipeline.modeldefinition.ModelInterpreter.inDeclarativeAgent(jar:file:/data/program/jenkins/plugins/pipeline-model-definition/WEB-INF/lib/pipeline-model-definition.jar!/org/jenkinsci/plugins/pipeline/modeldefinition/ModelInterpreter.groovy:369)
	at org.jenkinsci.plugins.pipeline.modeldefinition.ModelInterpreter.inDeclarativeAgent(jar:file:/data/program/jenkins/plugins/pipeline-model-definition/WEB-INF/lib/pipeline-model-definition.jar!/org/jenkinsci/plugins/pipeline/modeldefinition/ModelInterpreter.groovy:368)
	at org.jenkinsci.plugins.pipeline.modeldefinition.ModelInterpreter.call(jar:file:/data/program/jenkins/plugins/pipeline-model-definition/WEB-INF/lib/pipeline-model-definition.jar!/org/jenkinsci/plugins/pipeline/modeldefinition/ModelInterpreter.groovy:95)
	at ___cps.transform___(Native Method)
	at com.cloudbees.groovy.cps.impl.PropertyishBlock$ContinuationImpl.get(PropertyishBlock.java:74)
	at com.cloudbees.groovy.cps.LValueBlock$GetAdapter.receive(LValueBlock.java:30)
	at com.cloudbees.groovy.cps.impl.PropertyishBlock$ContinuationImpl.fixName(PropertyishBlock.java:66)
	at sun.reflect.GeneratedMethodAccessor289.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:497)
	at com.cloudbees.groovy.cps.impl.ContinuationPtr$ContinuationImpl.receive(ContinuationPtr.java:72)
	at com.cloudbees.groovy.cps.impl.ConstantBlock.eval(ConstantBlock.java:21)
	at com.cloudbees.groovy.cps.Next.step(Next.java:83)
	at com.cloudbees.groovy.cps.Continuable$1.call(Continuable.java:173)
	at com.cloudbees.groovy.cps.Continuable$1.call(Continuable.java:162)
	at org.codehaus.groovy.runtime.GroovyCategorySupport$ThreadCategoryInfo.use(GroovyCategorySupport.java:122)
	at org.codehaus.groovy.runtime.GroovyCategorySupport.use(GroovyCategorySupport.java:261)
	at com.cloudbees.groovy.cps.Continuable.run0(Continuable.java:162)
	at org.jenkinsci.plugins.workflow.cps.SandboxContinuable.access$001(SandboxContinuable.java:19)
	at org.jenkinsci.plugins.workflow.cps.SandboxContinuable$1.call(SandboxContinuable.java:35)
	at org.jenkinsci.plugins.workflow.cps.SandboxContinuable$1.call(SandboxContinuable.java:32)
	at org.jenkinsci.plugins.scriptsecurity.sandbox.groovy.GroovySandbox.runInSandbox(GroovySandbox.java:108)
	at org.jenkinsci.plugins.workflow.cps.SandboxContinuable.run0(SandboxContinuable.java:32)
	at org.jenkinsci.plugins.workflow.cps.CpsThread.runNextChunk(CpsThread.java:174)
	at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.run(CpsThreadGroup.java:330)
	at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.access$100(CpsThreadGroup.java:82)
	at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:242)
	at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:230)
	at org.jenkinsci.plugins.workflow.cps.CpsVmExecutorService$2.call(CpsVmExecutorService.java:64)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at hudson.remoting.SingleLaneExecutorService$1.run(SingleLaneExecutorService.java:112)
	at jenkins.util.ContextResettingExecutorService$1.run(ContextResettingExecutorService.java:28)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)