[JENKINS-50863] list.empty broken in pipeline scripts

Since upgrading to Pipeline:Groovy 2.48, the .empty property of List objects gives very strange results, whose boolean value in particular is the reverse of the expected.

When executing the following script as a pipeline (testet via "Replay" and replacing the existing script by this) gives weird output:

 Script

x = [] as List

println x

println x.isEmpty()

println x.empty

x<<"hello"

println x

println x.isEmpty()

println x.empty

Expected output

[Pipeline] echo

[]

[Pipeline] echo

true

[Pipeline] echo

true

[Pipeline] echo

[hello]

[Pipeline] echo

false

[Pipeline] echo

false

[Pipeline] End of Pipeline

Actual output

[Pipeline] echo

[]

[Pipeline] echo

true

[Pipeline] echo

[]

[Pipeline] echo

[hello]

[Pipeline] echo

false

[Pipeline] echo

[false]

[Pipeline] End of Pipeline

Downgrading the Pipeline:Groovy plugin to 2.47 fixes it; after upgrading again, the weird behaviour is back.

Workaround

For the moment, I can live with calling isEmpty() instead of accessing empty.

further considerations

I have not tested whether any other properties besides .empty are affected.

---
Originally reported by hjholtz, imported from: list.empty broken in pipeline scripts

• status: Open
  
• priority: Minor
  
• component(s): workflow-cps-plugin
  
• label(s): complex-cps-code, regression, triaged-2018-11
  
• resolution: Unresolved
  
• votes: 2
  
• watchers: 9
  
• imported: 2025-12-07
  

Raw content of original issue

Since upgrading to Pipeline:Groovy 2.48, the .empty property of List objects gives very strange results, whose boolean value in particular is the reverse of the expected.


When executing the following script as a pipeline (testet via "Replay" and replacing the existing script by this) gives weird output:

 Script



x = [] as List

println x

println x.isEmpty()

println x.empty

x<<"hello"

println x

println x.isEmpty()

println x.empty





Expected output



[Pipeline] echo

[]

[Pipeline] echo

true

[Pipeline] echo

true

[Pipeline] echo

[hello]

[Pipeline] echo

false

[Pipeline] echo

false

[Pipeline] End of Pipeline





Actual output



[Pipeline] echo

[]

[Pipeline] echo

true

[Pipeline] echo

[]

[Pipeline] echo

[hello]

[Pipeline] echo

false

[Pipeline] echo

[false]

[Pipeline] End of Pipeline





Downgrading the Pipeline:Groovy plugin to 2.47 fixes it; after upgrading again, the weird behaviour is back.


Workaround


For the moment, I can live with calling isEmpty() instead of accessing empty.


further considerations


I have not tested whether any other properties besides .empty are affected.

environment

```
Ubuntu 16.04.3 64bit

OpenJDK 1.8.0_151

Jenkins 2.89.4

Pipeline:Groovy 2.48
```

Start by reproducing the pipeline script from the issue with Pipeline:Groovy 2.48, then compare it with 2.47 and inspect the workflow-cps-plugin implementation and its existing tests. Done means List.empty returns the expected boolean and value behavior for both empty and non-empty lists, with regression coverage for the reported script.

Written by the indexing model from the issue text.