Git: Clone without parameters leds to RejectedAccessException

[phaenr]

Initializing the git object with credentials and later on try to clone a repository providing only the url runs into an error.
Executing the 'containsKey' method on a string does not result in a MissingMethodException on jenkins but into a RejectedAccessException.

Source

def git = git = script.cesBuildLib.Git.new(script, helmConfig.credentialsId)
// do some other stuff

// finally provide a url and clone runs into the given issue below
git helmConfig.repositoryUrl

org.jenkinsci.plugins.scriptsecurity.sandbox.RejectedAccessException: Scripts not permitted to use method groovy.lang.GroovyObject invokeMethod java.lang.String java.lang.Object (org.codehaus.groovy.runtime.GStringImpl containsKey java.lang.String)
	at org.jenkinsci.plugins.scriptsecurity.sandbox.whitelists.StaticWhitelist.rejectMethod(StaticWhitelist.java:270)
	at org.jenkinsci.plugins.scriptsecurity.sandbox.groovy.SandboxInterceptor.onMethodCall(SandboxInterceptor.java:159)
	at org.jenkinsci.plugins.scriptsecurity.sandbox.groovy.SandboxInterceptor.onMethodCall(SandboxInterceptor.java:142)
	at org.kohsuke.groovy.sandbox.impl.Checker$1.call(Checker.java:161)
	at org.kohsuke.groovy.sandbox.impl.Checker.checkedCall(Checker.java:165)
	at com.cloudbees.groovy.cps.sandbox.SandboxInvoker.methodCall(SandboxInvoker.java:17)
	at com.cloudogu.ces.cesbuildlib.Git.git(Git.groovy:52)
	at com.cloudogu.ces.cesbuildlib.Git.call(Git.groovy:40)
	at com.cloudogu.gitopsbuildlib.deployment.helm.repotype.GitRepo.getHelmChartFromGitRepo(GitRepo.groovy:35)
	at ___cps.transform___(Native Method)
	at com.cloudbees.groovy.cps.impl.ContinuationGroup.methodCall(ContinuationGroup.java:86)
	at com.cloudbees.groovy.cps.impl.FunctionCallBlock$ContinuationImpl.dispatchOrArg(FunctionCallBlock.java:113)
	at com.cloudbees.groovy.cps.impl.FunctionCallBlock$ContinuationImpl.fixArg(FunctionCallBlock.java:83)
	at sun.reflect.GeneratedMethodAccessor92.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at com.cloudbees.groovy.cps.impl.ContinuationPtr$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:174)
	at com.cloudbees.groovy.cps.Continuable$1.call(Continuable.java:163)
	at org.codehaus.groovy.runtime.GroovyCategorySupport$ThreadCategoryInfo.use(GroovyCategorySupport.java:129)
	at org.codehaus.groovy.runtime.GroovyCategorySupport.use(GroovyCategorySupport.java:268)
	at com.cloudbees.groovy.cps.Continuable.run0(Continuable.java:163)
	at org.jenkinsci.plugins.workflow.cps.SandboxContinuable.access$001(SandboxContinuable.java:18)
	at org.jenkinsci.plugins.workflow.cps.SandboxContinuable.run0(SandboxContinuable.java:51)
	at org.jenkinsci.plugins.workflow.cps.CpsThread.runNextChunk(CpsThread.java:185)
	at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.run(CpsThreadGroup.java:400)
	at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.access$400(CpsThreadGroup.java:96)
	at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:312)
	at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:276)
	at org.jenkinsci.plugins.workflow.cps.CpsVmExecutorService$2.call(CpsVmExecutorService.java:67)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at hudson.remoting.SingleLaneExecutorService$1.run(SingleLaneExecutorService.java:136)
	at jenkins.util.ContextResettingExecutorService$1.run(ContextResettingExecutorService.java:28)
	at jenkins.security.ImpersonatingExecutorService$1.run(ImpersonatingExecutorService.java:59)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)

[schnatterer]

Another interesting thing to note here is that the Jenkins git step seems not work if the remote repo does not have a master branch.
That is, not passing a branch parameter to git when there is no master branch will also result in an exception. Tested with git plugin 4.7.1.