I use variable to select a branch which will be built.

I can have different pipelines at different branches and I do not want to create several builds on each branch.

Then I do it I see that the variable does not evaluate.
hudson.plugins.git.GitException: Command "git fetch --tags --progress origin +refs/heads/${BUILD_BRANCH}:refs/remotes/origin/${BUILD_BRANCH} --prune" returned status code 128:
stdout:
stderr: perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
LANGUAGE = (unset),
LC_ALL = (unset),
LANG = "C.UTF-8"
are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
fatal: Couldn't find remote ref refs/heads/${BUILD_BRANCH}
fatal: The remote end hung up unexpectedly

at org.jenkinsci.plugins.gitclient.CliGitAPIImpl.launchCommandIn(CliGitAPIImpl.java:1996)
at org.jenkinsci.plugins.gitclient.CliGitAPIImpl.launchCommandWithCredentials(CliGitAPIImpl.java:1715)
at org.jenkinsci.plugins.gitclient.CliGitAPIImpl.access$300(CliGitAPIImpl.java:72)
at org.jenkinsci.plugins.gitclient.CliGitAPIImpl$1.execute(CliGitAPIImpl.java:405)
at jenkins.plugins.git.GitSCMFileSystem$BuilderImpl.build(GitSCMFileSystem.java:351)
at jenkins.scm.api.SCMFileSystem.of(SCMFileSystem.java:196)
at jenkins.scm.api.SCMFileSystem.of(SCMFileSystem.java:172)
at org.jenkinsci.plugins.workflow.cps.CpsScmFlowDefinition.create(CpsScmFlowDefinition.java:107)
at org.jenkinsci.plugins.workflow.cps.CpsScmFlowDefinition.create(CpsScmFlowDefinition.java:67)
at org.jenkinsci.plugins.workflow.job.WorkflowRun.run(WorkflowRun.java:271)
at hudson.model.ResourceController.execute(ResourceController.java:97)
at hudson.model.Executor.run(Executor.java:429)
Finished: FAILURE