[JENKINS-40134] Groovy truth issue in Pipeline script

A Jenkins pipeline script combining two String values with a logical AND (&& operator) does not behave as expected:

'' && '' -> false

'a' && 'b' -> 'b'

'a' != '' && 'b != '' -> true

So when combining two non empty values the result is not of type boolean but the second value of type String.

The following script demonstrates this behavior:

node {

    def doit = { String s1, String s2 ->

def p = { v -> "'$v' (${v.class})" }

    

echo "s1 = ${p s1}, s2 = ${p s2}"

echo "s1 && s2 = ${p s1 && s2}"

echo "s1 != '' && s2 != '' = ${p s1 != '' && s2 != ''}"

    }

 

    doit '', ''

    doit 'foo', 'bar'

}

Console of an example run in my environment:

---
Originally reported by m_olk, imported from: Groovy truth issue in Pipeline script

• status: Open
  
• priority: Minor
  
• component(s): workflow-cps-plugin
  
• label(s): complex-cps-code, pipeline, triaged-2018-11
  
• resolution: Unresolved
  
• votes: 2
  
• watchers: 3
  
• imported: 2025-12-07
  

Raw content of original issue

A Jenkins pipeline script combining two String values with a logical AND (&& operator) does not behave as expected:




'' && '' -> false

'a' && 'b' -> 'b'

'a' != '' && 'b != '' -> true





So when combining two non empty values the result is not of type boolean but the second value of type String. 


The following script demonstrates this behavior:




node {

    def doit = { String s1, String s2 ->

        def p = { v -> "'$v' (${v.class})" }

    

        echo "s1 = ${p s1}, s2 = ${p s2}"

        echo "s1 && s2 = ${p s1 && s2}"

        echo "s1 != '' && s2 != '' = ${p s1 != '' && s2 != ''}"

    }

 

    doit '', ''

    doit 'foo', 'bar'

}





Console of an example run in my environment:

  

• environment: Jenkins 2.9, Docker container, Oracle OpenJDK 1.8.0_91-8u91-b14-1~bpo8+1-b14 64-Bit Server VM, Linux 4.4.0-47-generic

1 attachment

- [Screen Shot 2016-11-30 at 22.58.37.png](https://issues.jenkins.io/secure/attachment/35048/Screen%20Shot%202016-11-30%20at%2022.58.37.png)
> 

No source file or test is named; start by reproducing the supplied Jenkins Pipeline example in workflow-cps-plugin and compare the reported String and boolean results. Done means the intended behavior for logical AND is agreed and the example no longer exhibits the unexpected result, with coverage for the shown cases.

Written by the indexing model from the issue text.