not change the behavior for existing packages that subclass from
spack.Package.
If a package subclasses spack.StagedPackage instead of spack.Package,
the install() phase (run inside a forked process) is now separated
into sub-stages:
a) spconfig: Generate a script spconfig.py that will configure the
package (eg by running CMake or ./configure) This is for use if
the user wishes to build externally from Spack. Therefore, the
Spack compiler wrappers are NOT used here. Currently, that
means that RPATH support is up to the user.
b) configure: Configure the project (eg: runs configure, CMake,
etc). This will configure it for use within Spack, using the
Spack wrapper.
c) build: eg: "make"
d) install: eg: "install"
If one chooses to use StagedPackage instead of Package, then one must
implement each of the install sub-stages as a separate method.
StagedPackage.install() then calls each of the sub-stages as
appropriate.
StagedPackage can be configured to only run certain sub-stages. This
is done by setting the optional kwarg install_phases when calling
do_install(). Setting install_phases() ONLY has an effect on
StagedPackage, not on any existing packages. By default,
install_phases is set to make StagedPackage run the same stages that
are normally run for any package: configure, build, install (and NOT
spconfig).
The ability for Spack to run stages selectively for StagedPackage
instances will enable new functionality. For example, explicit
CMake/Autotools helpers that allow Spack to help configure a user's
project without fetching, building or installing it.
-------------
One implementation of StagedPackage is provided, CMakePackage. This
has the following advantage for CMake-based projects over using the
standard Package class:
a) By separating out the phases, it enables future new functionality
for packages that use it.
b) It provides an implementation of intall_spconfig(), which will
help users configure their CMake-based projects.
CMakePackage expects users to implement configure_args() and
configure_env(). These methods provide the package-specific arguments
and environment needed to properly configure the package. They are
placed in separated functions because they are used in both the
spconfig and configure stages.
TODO:
1. Generate spconfig.py scripts that are more readable. This allows
the users to understand how their project is configured.
2. Provide a practical way for the user to ACCESS the spconfig stage
without building the project through Spack.
3. The CMAKE_TRANSITIVE_INCLUDE_PATH stuff needs to be reworked; it
should be considered provisional for now.
4. User of Autotools might wish to make a similar ConfigurePackage
subclass of StagedPackage.
---------------
One package using CMakePackage is introduced. See ibmisc/package.py.
- This version provides updates to provided cmake scripts that are required
for building cmake-gui.
+ Provide download/build instructions for version 3.5.0.
- When building the +qt variant, add a validate function to ensure that
qt-5.4.0 is not used (this version of qt has errors related to cmake).
