diff options
| -rw-r--r-- | lib/spack/docs/packaging_guide.rst | 28 |
1 files changed, 18 insertions, 10 deletions
diff --git a/lib/spack/docs/packaging_guide.rst b/lib/spack/docs/packaging_guide.rst index cb5835c5c2..156b5a7eb2 100644 --- a/lib/spack/docs/packaging_guide.rst +++ b/lib/spack/docs/packaging_guide.rst @@ -1967,22 +1967,29 @@ exactly what kind of a dependency you need. For example: depends_on('cmake', type='build') depends_on('py-numpy', type=('build', 'run')) depends_on('libelf', type=('build', 'link')) + depends_on('py-pytest', type='test') The following dependency types are available: -* **"build"**: made available during the project's build. The package will - be added to ``PATH``, the compiler include paths, and ``PYTHONPATH``. - Other projects which depend on this one will not have these modified - (building project X doesn't need project Y's build dependencies). -* **"link"**: the project is linked to by the project. The package will be - added to the current package's ``rpath``. -* **"run"**: the project is used by the project at runtime. The package will - be added to ``PATH`` and ``PYTHONPATH``. +* **"build"**: the dependency will be added to the ``PATH`` and + ``PYTHONPATH`` at build-time. +* **"link"**: the dependency will be added to Spack's compiler + wrappers, automatically injecting the appropriate linker flags, + including ``-I``, ``-L``, and RPATH/RUNPATH handling. +* **"run"**: the dependency will be added to the ``PATH`` and + ``PYTHONPATH`` at run-time. This is true for both ``spack load`` + and the module files Spack writes. +* **"test"**: the dependency will be added to the ``PATH`` and + ``PYTHONPATH`` at build-time. The only difference between + "build" and "test" is that test dependencies are only built + if the user requests unit tests with ``spack install --test``. One of the advantages of the ``build`` dependency type is that although the dependency needs to be installed in order for the package to be built, it can be uninstalled without concern afterwards. ``link`` and ``run`` disallow -this because uninstalling the dependency would break the package. +this because uninstalling the dependency would break the package. Another +consequence of this is that ``build``-only dependencies do not affect the +hash of the package. The same is true for ``test`` dependencies. If the dependency type is not specified, Spack uses a default of ``('build', 'link')``. This is the common case for compiler languages. @@ -2003,7 +2010,8 @@ package. In that case, you could say something like: .. code-block:: python - variant('mpi', default=False) + variant('mpi', default=False, description='Enable MPI support') + depends_on('mpi', when='+mpi') ``when`` can include constraints on the variant, version, compiler, etc. and |