Documentation/Nightly/Developers/Tutorials/MigrationGuide/SlicerExtension

Slicer Extension updates

Slicer 4.9: Explicit initialization of CMAKE_BUILD_TYPE not needed anymore

Following r26978, calling find_package(Slicer REQUIRED) and include(${Slicer_USE_FILE}) initializes CMAKE_BUILD_TYPE and ensures the variables CMAKE_BUILD_TYPE and CMAKE_CONFIGURATION_TYPES are passed to all external projects when configuring SuperBuild based extension.

The module SlicerInitializeBuildType is automatically included in UserSlicer.

Slicer 4.9: Subversion not required anymore

Following r27060, Subversion is not required anymore.

Slicer 4.9: Support EP_GIT_PROTOCOL and use of ExternalProject_SetIfNotDefined for setting GIT_REPOSITORY, GIT_TAG and alike

Following r26957, extension may use the following convention to define GIT_REPOSITORY and GIT_TAG, this allows developer to override the value before the first configuration by setting the corresponding environment variable, or by explicitly configuring the project with that variable.

The option EP_GIT_PROTOCOL is also already set in ExternalProjectDependency module included by Slicer and its value is updated based on the <SUPERBUILD_TOPLEVEL_PROJECT>_USE_GIT_PROTOCOL option.

  ExternalProject_SetIfNotDefined(
    ${CMAKE_PROJECT_NAME}_${proj}_GIT_REPOSITORY
    "${EP_GIT_PROTOCOL}://github.com/jcfr/shape4D.git"
    QUIET
    )

  ExternalProject_SetIfNotDefined(
    ${CMAKE_PROJECT_NAME}_${proj}_GIT_TAG
    "12fef84ca2a56feffc59d8159bdadd2ce4a4138e" # slicersalt-2018-01-22-c74c766a4c
    QUIET
    )

See:

• https://cmake-artichoke.readthedocs.io/en/latest/ExternalProjectDependency.html#variable:EP_GIT_PROTOCOL
• https://cmake-artichoke.readthedocs.io/en/latest/ExternalProjectDependency.html#function:ExternalProject_SetIfNotDefined

Slicer 4.9: Use ExternalProject_AlwaysConfigure to force reconfigure of inner project

Following r26551, the function ExternalProject_AlwaysConfigure may be used to ensure the inner project is always reconfigured.

Using the `BUILD_ALWAYS` option supported by ExternalProject_Add will not have the intended effect.

See https://cmake-artichoke.readthedocs.io/en/latest/ExternalProjectDependency.html#function:ExternalProject_AlwaysConfigure