repeatableProperty in Jenkins Global Configuration

[Ullrich Hafner]

I have a repeatableProperty in Jenkins Global Configuration page (see https://github.com/jenkinsci/warnings-ng-plugin/pull/266).

Expanded snippet:

<f:section title="${%Warnings Next Generation Plugin Global Settings}">
  <f:entry title="${%sourceDirectories.title}" description="${%sourceDirectories.description}">
    <f:repeatableProperty field="sourceDirectories">
      <f:entry title="">
        <div align="right">
          <f:repeatableDeleteButton />
        </div>
      </f:entry>
    </f:repeatableProperty>
  </f:entry>

</f:section>

(And a describable config.jelly)

<f:entry title="${%Absolute path of folder}" field="path">
  <f:textbox/>
</f:entry>

I can successfully add entries and delete entries in the UI. However, if I remove the last element in the UI then the empty list ist not saved. More precisely, the data bound setter 

/**
 * Sets the list of source directories to the specified elements. Previously set directories will be removed.
 *
 * @param sourceDirectories
 *         the source directories that contain the affected files
 */
@DataBoundSetter
public void setSourceDirectories(final List<SourceDirectory> sourceDirectories) {

...

Is not called if I remove all elements in the UI (it is called for 1,…,n elements). Has anyone an idea what I am making wrong? 

[Jesse Glick]

On Tue, Nov 12, 2019 at 5:53 PM Ullrich Hafner <ullrich...@gmail.com> wrote:
> if I remove the last element in the UI then the empty list ist not saved. More precisely, the data bound setter […]

> Is not called if I remove all elements in the UI (it is called for 1,…,n elements).

This is a well-known limitation in databinding. The workaround is to override a `configSubmit` or whatever method to first null out / clear the list, then call super. Example:

https://github.com/jenkinsci/ui-samples-plugin/blob/7d0fe2b32204a7fe0ec6adb6815e65d48b0dd54e/src/main/java/jenkins/plugins/ui_samples/HeteroList.java#L81