If I use a String Parameter in my branch as shown in the screenshot. Then ReBase happens successfully and all Build steps are also executed properly. But in Post Build when I am using [Integrate to Upstream on successful build]  then the following error is displayed. If I replace the parameterized string manually then it works properly.

Error:

ERROR: [flexible-publish] Integrate to upstream upon successful build (jenkins.plugins.svnmerge.IntegrationPublisher@169dcb53) aborted due to exception
java.lang.NullPointerException
at hudson.scm.SVNRevisionState.getRevision(SVNRevisionState.java:24)
at jenkins.plugins.svnmerge.IntegrateAction.getSvnInfo(IntegrateAction.java:149)
at jenkins.plugins.svnmerge.IntegrateAction.perform(IntegrateAction.java:165)
at jenkins.plugins.svnmerge.IntegrationPublisher.perform(IntegrationPublisher.java:51)
at org.jenkins_ci.plugins.flexible_publish.builder.FailAtEndBuilder.perform(FailAtEndBuilder.java:104)
at org.jenkins_ci.plugins.run_condition.BuildStepRunner$2.run(BuildStepRunner.java:110)
at org.jenkins_ci.plugins.run_condition.BuildStepRunner$Fail.conditionalRun(BuildStepRunner.java:154)
at org.jenkins_ci.plugins.run_condition.BuildStepRunner.perform(BuildStepRunner.java:105)
at org.jenkins_ci.plugins.flexible_publish.strategy.FailAtEndExecutionStrategy.perform(FailAtEndExecutionStrategy.java:85)
at org.jenkins_ci.plugins.flexible_publish.ConditionalPublisher.perform(ConditionalPublisher.java:206)
at org.jenkins_ci.plugins.flexible_publish.FlexiblePublisher.perform(FlexiblePublisher.java:124)
at hudson.tasks.BuildStepMonitor$2.perform(BuildStepMonitor.java:32)
at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:741)
at hudson.model.AbstractBuild$AbstractBuildExecution.performAllBuildSteps(AbstractBuild.java:690)
at hudson.model.Build$BuildExecution.post2(Build.java:186)
at hudson.model.AbstractBuild$AbstractBuildExecution.post(AbstractBuild.java:635)
at hudson.model.Run.execute(Run.java:1878)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
at hudson.model.ResourceController.execute(ResourceController.java:97)
at hudson.model.Executor.run(Executor.java:427)
Build step 'Flexible publish' changed build result to FAILURE
Build step 'Flexible publish' marked build as failure
Finished: FAILURE

Please help me as my branching strategy is very dynamic and hence cannot keep creating the project manually.