As was identified later, it appears that this is happening because Slicer extensions build system ignores the icon specified in the s4ext file, and instead uses the one from CMakeLists.txt.

It is not clear whether this is a bug, or intentional behavior.

Is is clear though that this situation is rather confusing to the developer...

Added note to documentation to clarify: https://www.slicer.org/wiki/Documentation/Nightly/Developers/Extensions/DescriptionFile.

For Slicer5, a new extension description format should be created and the redundancy between CMakeLists.txt and s4ext file should be removed. See discussion at https://www.slicer.org/wiki/Documentation/Labs/ExtensionsMetadata.

I will confirm this tomorrow after I see the dashboard, but -- related to this issue -- it looks like build_subdirectory is ignored in CMakeLists.txt, and is taken from s4ext...

Confirmed - build_subdirectory is ignored in CMakeLists.txt. For the superbuild extensions, it must be populated in s4ext. Demonstrated on the example of PkModeling extension that we recently moved to superbuild.

Indeed, the value of build_subdirectory from the description is only used by the extension build system to find out in which sub directory the "packageupload" target should be built from. See [1]

[1] https://www.slicer.org/wiki/Documentation/Nightly/Developers/FAQ#How_to_upload_an_extension_.3F

Closing . URL was improperly specified.

In the future, we will improve how metadata are specified to avoid similar issue.

For the record:

• metadata, file to be compiled, resources, ... are all specified in the CMakeLists.txt
• the extension description file is currently a by product of the configuration/build step