Direct users of IMPORTED targets treat INTERFACE_INCLUDE_DIRECTORIES
as SYSTEM, after commit a63fcbcb (Always consider includes from IMPORTED
targets to be SYSTEM., 2013-08-29). It was intended that transitive
use of an IMPORTED target would have the same behavior, but that
did not work. The implementation processed only direct dependencies
in cmTarget::FinalizeSystemIncludeDirectories.
Implement transitive evaluation of dependencies by traversing the
link interface of each target in the link implementation.
The error messages were incorrect (reporting that the expression
requires one or two parameters), and repeated. Remove the now-unused
ZeroOrMoreParameters enum value.
There is no need to allow EXCLUDE_* properties, because an
INTERFACE_LIBRARY has no direct build output.
IMPORTED_LINK_INTERFACE_LANGUAGES are relevant only to static
libraries.
VERSION is relevant only to the filename of direct build outputs,
which INTERFACE_LIBRARY does not have.
Describe how to define a buildsystem of binary targets, how to
express dependencies between them, how to add build specifications,
how to specify usage requirements, transitive and compatible
propagation and the various pseudo targets.
Test that it is an error to read a number-compatible property to
determine the link implementation. An alternative would be to
consider the value to be "0", however, that is too arbitrary
given the use-cases of this feature. Values from this feature may
be used in setting a define, where "0" may have special or invalid
meaning and should be explicit.
If the dependent target sets the property to boolean false, ensure
that that appears in the debug report. Previously, the report
output contained whether the property was consistent among dependencies,
displaying 'TRUE', instead of the content of the property, which may
be 'FALSE'.
Return a std::pair from the consistentProperty method. This makes
it possible to make the return value for string types easier to
reason about. The return value of consistentProperty was previously
set to an empty static string to emulate a 'true' value for the caller
in commit 816b4a8a (cmTarget: Make consistentProperty
return consistent content., 2013-10-22). The pair makes the
consistency result properly typed.
Don't refer to 'both', but a 'mixture'. List all compatible interface
property types possible.
Add another test for a mixture of three compatibilities.
The include_directories() and add_compile_options() commands
should not append to the corresponding target property for IMPORTED
targets. This is already the case for add_definitions().
The modern way to create configuration dependent content is using
generator expressions in the main export file. The only non-deprecated
property still generated in the configuration-specific files are
IMPORTED_LOCATION_<CONFIG>
INTERFACE_LIBRARY targets have no location, and no need for those
files.
The next version is 3.0.0, not 2.8.13.
The version generated in the export file should be updated in
the release branch in both cmExportInstallFileGenerator and
cmExportBuildFileGenerator.