[JENKINS-60511] parameterized project triggered with empty parameters from pipeline's for loop

Scenario

I have two pipeline jobs 'Parent' and 'Child' where 'Child' is parameterized and triggered (fire+forget) from 'Parent' multiple times. The total amount of 'Child' jobs triggered from 'Parent' are variable and depend on external parameters.

 

// Parent.jenkinsfile

pipeline {

  agent any

  stages {

    stage('Trigger Child') {

      steps {

script {

  for(int i = 0; i < 3; ++i) {

    build(

      job: 'Child',

      parameters: [

string(name: 'alpha', value: 'test'),

string(name: 'beta', value: "${i}")

      ],

      wait: false,

      propagate: false)

  }

}

      }

    }

  }

}

// Child.jenkinsfile

pipeline {

  agent any

  parameters {

    string(name: 'alpha', description: '', trim: true)

    string(name: 'beta', description: '', trim: true)

  }

  stages {

    stage('Hello') {

      steps {

buildName "${params.alpha} ${params.beta}"

      }

    }

  }

}

Observed Behaviour

From any run of 'Parent', 'Child' is getting triggered for each set of parameter values AND one additional time with all parameters set to empty values (or their defaults).

In the example above, 'Child' is triggered with the following values:

1. alpha="", beta="null"  <-- should not be there


2. alpha="test", beta="0"


3. alpha="test", beta="1"


4. alpha="test", beta="2"

Import Note

This spurious job without parameter values is not being triggered when 'Parent' waits for the 'Child' to finish, i.e. if I set wait=true in the build step of 'Parent'.

 

---
Originally reported by tklatt, imported from: parameterized project triggered with empty parameters from pipeline's for loop

• status: Open
  
• priority: Major
  
• component(s): parameterized-trigger-plugin, pipeline-build-step-plugin
  
• label(s): Jenkinsfile, parameterized-trigger, pipeline
  
• resolution: Unresolved
  
• votes: 0
  
• watchers: 1
  
• imported: 2025-12-07
  

Raw content of original issue

Scenario


I have two pipeline jobs 'Parent' and 'Child' where 'Child' is parameterized and triggered (fire+forget) from 'Parent' multiple times. The total amount of 'Child' jobs triggered from 'Parent' are variable and depend on external parameters.


 



// Parent.jenkinsfile

pipeline {

  agent any

  stages {

    stage('Trigger Child') {

      steps {

        script {

          for(int i = 0; i < 3; ++i) {

            build(

              job: 'Child',

              parameters: [

                string(name: 'alpha', value: 'test'),

                string(name: 'beta', value: "${i}")

              ],

              wait: false,

              propagate: false)

          }

        }

      }

    }

  }

}







// Child.jenkinsfile

pipeline {

  agent any

  parameters {

    string(name: 'alpha', description: '', trim: true)

    string(name: 'beta', description: '', trim: true)

  }

  stages {

    stage('Hello') {

      steps {

        buildName "${params.alpha} ${params.beta}"

      }

    }

  }

}





Observed Behaviour


From any run of 'Parent', 'Child' is getting triggered for each set of parameter values AND one additional time with all parameters set to empty values (or their defaults).


In the example above, 'Child' is triggered with the following values:



	
alpha="", beta="null"  <--  should not be there

	
alpha="test", beta="0"

	
alpha="test", beta="1"

	
alpha="test", beta="2"



Import Note


This spurious job without parameter values is not being triggered when 'Parent' waits for the 'Child' to finish, i.e. if I set wait=true in the build step of 'Parent'.


 

environment

```
Jenkins 2.190.3 (as Docker container)

Parameterized Trigger plugin 2.36

Pipeline: Build Step 2.10
```