Simple Jenkins pipeline fails when I check an environment variable

Question

In my multibranch pipeline job, I can successfully access environment variables like this:

echo "$env.BRANCH_NAME"

But it throws and exception if I try to compare against that same environment variable:

if($env.BRANCH_NAME == 'master')
{
  echo "This is the master branch"
}

Here's the top of the error stack I'm given:

groovy.lang.MissingPropertyException: No such property: $env for class: groovy.lang.Binding
    at groovy.lang.Binding.getVariable(Binding.java:63)
    at org.jenkinsci.plugins.scriptsecurity.sandbox.groovy.SandboxInterceptor.onGetProperty(SandboxInterceptor.java:224)
    at org.kohsuke.groovy.sandbox.impl.Checker$4.call(Checker.java:241)
    at org.kohsuke.groovy.sandbox.impl.Checker.checkedGetProperty(Checker.java:238)
    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:4)

Do I need to do some sort of script approval here? I checked in Manage Jenkins -> In-Process Script Approval, but nothing is there.

Answer 1

Try to remove the dollar sign or use "${env.BRANCH_NAME}"

Answer 2

The earlier answer is correct, but for more information, the "$var" syntax is what is used within a string to interpolate the variable value into the string. Outside of a string, just reference the variable.