Skinparameters for sequence groups affect non-empty packages

[nkhancock]

The bug
The sequence skinparameters groupBorderColor and groupBorderThickness override the package skinparameters borderColor and borderThickness for packages that include other elements, such as classes.

groupBorderColor and groupBorderThickness do not affect packages that contain no elements.

This issue can be reproduced with PlantUML releases going back to at least plantuml-1.2022.12.

To Reproduce
The following PlantUML code can be used to reproduce this behavior.

@startuml

  skinparam arrowColor #limegreen

  skinparam Class {
    backgroundColor #white
    borderColor #limegreen
    borderThickness 1
  }

  skinparam Package {
    backgroundColor #white
    fontSize 11
    fontStyle normal
    borderColor #LimeGreen
    ' borderThickness 1
  }
  
  skinparam Sequence {
    actorBorderColor #darkgreen
    boxBackgroundColor #whitesmoke
    boxBorderColor #darkgrey
    groupBorderColor #black
    groupBorderThickness 3
    groupBackgroundColor #darkgrey
    lifeLineBorderColor #limegreen
    lifeLineBackgroundColor #limegreen
    participantBackgroundColor #limegreen
    participantBorderColor #limegreen
  }

  package "external-module" as external_module {
  }
  package "my-module" as my_module {
    class "my-class" as my_class
  }

  external_module +-- my_module
@enduml

Generating the above PlantUML code with release v1.2024.4 results in the following image:

Although the borderColor defined for packages is LimeGreen and the border of the package without any contents is LimeGreen, the border of the package containing the class is nevertheless black.

After some experimenting, I found that the skinparameter groupBorderColor for sequences caused this behavior. The same was true for borderThickness \ groupBorderThickness. There may be other such parameter pairs affected.

Note that if skinparameter groupBorderColor is not defined, the border color of the package with the class is LimeGreen as expected. If skinparameter groupBorderThickness is not defined, the border thickness of the package with the class is as expected. So it seems that if a groupBorder* skinparameter is not explicitly defined, the value defined for packages is not affected.

This can be reproduced by commenting out the parameters groupBorderColor and groupBorderThickness as shown in the following image:

Expected behavior
The borderColor and borderThickness defined as skinparamters of a package must apply to both empty packages and packages containing elements and not be affected by any other skinparameters, i.e., skinparameters for sequence groups.

Desktop (please complete the following information):

• OS: Windows 10
• IDE: PyCharm 2024.1.1
• Tested with PlantUML releases: 1.2022.12, 1.2023.2, 1.2024.4

[The-Lum]

Hello @nkhancock,

Instead using of old skinparam, you can now use style, as:

@startuml
<style>
arrow {LineColor #limegreen}
classDiagram {
    backgroundColor #white
    LineColor #limegreen
    LineThickness  1
}
package {
    backgroundColor #white
    fontSize 11
    fontStyle normal
    LineColor #LimeGreen
    LineThickness 1
}
sequenceDiagram {
  actor,participant {
    LineColor #darkgreen
  }
  group {
    BackgroundColor #darkgrey
    LineColor #black
    LineThickness 3
  }
  box {
    BackgroundColor #whitesmoke
    LineColor #whitesmoke
  }
  lifeLine {
    BackGroundColor #limegreen
    LineColor #limegreen
  }
}

</style>

  package "external-module" as external_module {
  }
  package "my-module" as my_module {
    class "my-class" as my_class
  }

  external_module +-- my_module
@enduml

See alslo doc. here:

• https://plantuml.com/style-evolution

Enjoy,
Regards,
Th.

[nkhancock]

@The-Lum : Thanks for this information.
Our project currently uses skinparam definitions in a global include file. I will have to investigate converting this to styles, which appears much more flexible.

Some initial quick attempts resulted in some unexpected behaviour such as style definitions for class diagrams affecting other skinparam definitions for other diagrams, such as packages. I'll have to investigate this further.

Are there any know issues when mixing stye definitions with skinparam definitions?