Since commit v2.8.2~105^2~2 (Teach CMake Policies about tweak version
component, 2010-04-23), cmPolicies has known how to handle a policy
introduced in a tweak version. This was done back when we introduced
policies with the current development date version and later updated it
to the release version. Now we always introduce policies using the next
expected release version and explicitly set the policy to test the NEW
behavior.
CMake Policies (or any other features) should never be introduced in a
tweak (bugfix) release, so drop the infrastructure that allows this.
Teach the project() command to set variables
{PROJECT,<PROJECT-NAME>}_VERSION{,_MAJOR,_MINOR,_PATCH,_TWEAK}
holding the project version number and its components. Add project()
command option "VERSION" to specify the version explicitly, and default
to the empty string when it is not given.
Since this clears variables when no VERSION is given, this may change
behavior for existing projects that set the version variables themselves
prior to calling project(). Add policy CMP0048 for compatibility.
Suggested-by: Alex Neundorf <neundorf@kde.org>
Introduce policy CMP0047 to control resetting the id for
compatibility.
De-duplicate content in the QNX platform file by including the GNU
one. QNX is a form of GNU platform.
Do not clear CMAKE_SHARED_LIBRARY_${lang}_FLAGS variables. They
are populated again later by the Compiler/GNU.cmake file anyway.
Modify the CMAKE_CXX_COMPILE_OBJECT variable only when the QCC
compiler id is in use, and the language is CXX. Use the QNX
recommended flag for QCC instead of the gcc compatible -x flag.
Populate new module files to handle system includes and depfiles
when using the QCC compiler.
Remove code which unsets the system include and depfiles related
variables. When a GNU driver is used instead of the QCC one, the
appropriate flags will be used. These variables were previously
cleared for lowest-common-denominator compatibility with both
drivers.
Diagnostics which check the sanity of exported include paths
previously skipped over any path containing a generator expression.
Introduce a policy to issue an error message in such cases.
The export files created in the OLD behavior are not usable, because
they contain relative paths or paths to the source or build location
which are not suitable for use on installation. CMake will report an
error on import.
Teach add_custom_target to check the policy too. Extend the policy to
disallow reserved target names that we use for builtin targets like
"all".
Extend the RunCMake.CMP0037 test to cover these cases.
Introduce a policy to control the behavior.
The AliasTargets unit test already tests that using a
double-semicolon in the name is not an error. Change the ExportImport
test to use a namespace with a double-semicolon too.
The full policy documentation was moved to Help/policy/*.rst by commit
f051814e (Convert builtin help to reStructuredText source files,
2013-10-15). We no longer need the builtin string literals.
In commit 87cc62ca (Drop "full" documentation output types, 2013-09-13)
we dropped code using the LongDescription field of policy definitions.
We need to follow it up with a change similar to commit 399e9c46 (Drop
builtin property documentation, 2013-09-16) to remove the policy
documentation. Do that now. Keep the short description as it is used
in policy error and warning messages.
We will no longer support full documentation generation from executables
and will instead generate documentation with other tools. Disable (with
a warning left behind) the command-line options:
--copyright
--help-compatcommands
--help-full
--help-html
--help-man
Drop supporting code. Drop manual sections generation from executables.
Remove internal documentation construction APIs. Drop unused sections
See Also, Author, Copyright, Compat Commands, Custom Modules.
The final location and name of a build-target is not determined
until generate-time. However, reading the LOCATION property from
a target is currently allowed at configure time. Apart from creating
possibly-erroneous results, this has an impact on the implementation
of cmake itself, and prevents some major cleanups from being made.
Disallow reading LOCATION from build-targets with a policy. Port some
existing uses of it in CMake itself to use the TARGET_FILE generator
expression.
The parent commit introduced a separate "AppleClang" compiler id for
Apple's Clang distribution. Add a policy in order to support projects
that expect this compiler's id to be just "Clang". When the policy is
OLD or not set, map AppleClang back to Clang. Continue to use the
AppleClang id internally while enabling the language, but set the
CMAKE_<LANG>_COMPILER_ID after project() or enable_language() to the
compatible value for use by project code.
Currently, export() is executed at configure-time.
One problem with this is that certain exported properties like
the link interface may not be complete at the point the export() is
encountered leading to an incorrect or incomplete exported
representation. Additionally, the generated IMPORTED_LOCATION
property may even be incorrect if commands following the export()
have an effect on it.
Another problem is that it requires the C++ implementation of cmake
to be capable of computing the exported information at configure time.
This is a limitation on the cleanup and maintenance of the code. At
some point in the future, this limitation will be dropped and more
implementation will be moved from cmTarget to cmGeneratorTarget.
Add a new signature to help populate INTERFACE_LINK_LIBRARIES and
LINK_LIBRARIES cleanly in a single call. Add policy CMP0023 to control
whether the keyword signatures can be mixed with uses of the plain
signatures on the same target.
This property replaces the properties which
match (IMPORTED_)?LINK_INTERFACE_LIBRARIES(_<CONFIG>)?, and is enabled
for IMPORTED targets, and for non-IMPORTED targets only with a policy.
For static libraries, the INTERFACE_LINK_LIBRARIES property is
also used as the source of transitive usage requirements content.
Static libraries still require users to link to all entries in
their LINK_LIBRARIES, but usage requirements such as INCLUDE_DIRECTORIES
COMPILE_DEFINITIONS and COMPILE_OPTIONS can be restricted to only
certain interface libraries.
Because the INTERFACE_LINK_LIBRARIES property is populated unconditionally,
we need to compare the evaluated result of it with the link implementation
to determine whether to issue the policy warning for static libraries. For
shared libraries, the policy warning is issued if the contents of
the INTERFACE_LINK_LIBRARIES property differs from the contents of the
relevant config-specific old LINK_INTERFACE_LIBRARIES property.
Historically CMake has always expanded ${} variable references in the
values given to include_directories(), link_directories(), and
link_libraries(). This has been unnecessary since general ${}
evaluation syntax was added to the language a LONG time ago, but has
remained for compatibility with VERY early CMake versions.
For a long time the re-expansion was a lightweight operation because it
was only processed once at the directory level and the fast-path of
cmMakefile::ExpandVariablesInString was usually taken because values did
not have any '$' in them. Then commit d899eb71 (Call
ExpandVariablesInString for each target's INCLUDE_DIRECTORIES,
2012-02-22) made the operation a bit heavier because the expansion is
now needed on a per-target basis. In the future we will support
generator expressions in INCLUDE_DIRECTORIES with $<> syntax, so the
fast-path in cmMakefile::ExpandVariablesInString will no longer be taken
and re-expansion will be very expensive.
Add policy CMP0019 to skip the re-expansion altogether in NEW behavior.
In OLD behavior perform the expansion but improve the fast-path
heuristic to match ${} but not $<>. If the policy is not set then warn
if expansion actually does anything. We expect this to be encountered
very rarely in practice.
CMAKE_SHARED_LIBRARY_<lang>_FLAGS has flags on various platforms for a
variety of purposes that are correlated with shared libraries but not
exclusive to them. Refactor generation of these flags to use new
purpose-specific platform variables
CMAKE_<lang>_COMPILE_OPTIONS_DLL
CMAKE_<lang>_COMPILE_OPTIONS_PIC
CMAKE_<lang>_COMPILE_OPTIONS_PIE
Activate the DLL flags specifically for shared libraries. Add a new
POSITION_INDEPENDENT_CODE target property to activate PIC/PIE flags, and
default to true for shared libraries to preserve default behavior.
Initialize the new property from CMAKE_POSITION_INDEPENDENT_CODE to
allow easy global configuration in projects.
Although the default behavior is unchanged by this refactoring, the new
approach ignores CMAKE_SHARED_LIBRARY_<lang>_FLAGS completely. We must
leave it set in case projects reference the value. Furthermore, if a
project modifies CMAKE_SHARED_LIBRARY_<lang>_FLAGS it expects the new
value to be used. Add policy CMP0018 to handle compatibility with
projects that modify this platform variable.
Add a PositionIndependentCode test on platforms where we can get
meaningful results.
This patch makes include() and find_package() prefer cmake files
located in CMAKE_ROOT over those in CMAKE_MODULE_PATH.
This makes sure that the including file gets that file included
which it expects, i.e. the one from cmake with which it was tested.
It only changes behaviour when such an included file exists both
in CMAKE_MODULE_PATH and in CMAKE_ROOT.
This comes together with a new policy CMP0017, with default
behaviour it behaves as it always did, but warns.
With NEW behaviour it includes the file from CMAKE_ROOT
instead from CMAKE_MODULE_PATH. This fixes (if CMP0017 is set)
building KDE 4.5 with cmake >= 2.8.3.
Also a basic test for this policy in included.
Check CMAKE_POLICY_DEFAULT_CMP<NNNN> for a default when policy CMP<NNNN>
would otherwise be left unset. This allows users to set policies on the
command line when the project does not set them. One may do this to
quiet warnings or test whether a project will build with new behavior
without modifying code. There may also be cases when users want to
build an existing project release using new behavior for policies
unknown to the project at the time of the release.
When set to OLD, target_link_libraries() silently accepts if it is called
with only one argument and this one argument is not a target.
When set to NEW, this is an error. By default it is a warning now.
Alex
Add the [.tweak] version component throughout the policy implementation.
Document all components for the cmake_policy(VERSION) command. Record
the tweak level in which each policy was introduced (0 for all current
policies). In generated documentation we report the tweak level only if
it is not zero. This preserves existing documentation.
We create CMake Policy CMP0015 to make link_directories() treat relative
paths with respect to the source tree while retaining compatibility.
This makes it consistent with include_directories() and other commands.
Changes based on patch from Alex. See issue #9697.
The commit "modified the if command to address bug 9123 some" changed
the if() command behavior with respect to named boolean constants. It
introduced policy CMP0012 to provide compatibility. However, it also
changed behavior with respect to numbers (like '2') but did not cover
the change with the policy. Also, the behavior it created for numbers
is confusing ('2' is false).
This commit teaches if() to recognize numbers again, and treats them
like the C language does in terms of boolean conversion. We also fix
the CMP0012 check to trigger in all cases where the result of boolean
coersion differs from that produced by CMake 2.6.4.
We revert commit "Create CMake Policy CMP0015 to fix set(CACHE)" because
the NEW behavior of the policy breaks a valid use case:
# CMakeLists.txt
option(BUILD_SHARED_LIBS "..." ON)
add_library(mylib ...)
set(BUILD_SHARED_LIBS OFF) # we want only mylib to be shared
add_subdirectory(ThirdParty)
# ThirdParty/CMakeLists.txt
option(BUILD_SHARED_LIBS "..." ON)
# uh, oh, with NEW behavior this dir uses shared libs!!!
We'll re-introduce the policy later with a different change in behavior
to resolve the motivating case, which was more subtle but less common.
See issue #9008.
This converts the CMake license to a pure 3-clause OSI-approved BSD
License. We drop the previous license clause requiring modified
versions to be plainly marked. We also update the CMake copyright to
cover the full development time range.
The set(CACHE) and option() commands should always expose the cache
value. Previously we failed to expose the value when it was already set
if a local variable definition hid it. When set to NEW, this policy
tells the commands to always remove the local variable definition to
expose the cache value. See issue #9008.
Until now CMake accidentally accepted add_subdirectory() and subdirs()
calls referring to directories that do not contain a CMakeLists.txt
file. We introduce CMake Policy CMP0014 to make this case an error.
In CMake 2.6.3 and below we silently accepted duplicate build
directories whose build files would then conflict. At first this was
considured purely a bug that confused beginners but would not be used in
a real project. In CMake 2.6.4 we explicitly made it an error.
However, some real projects took advantage of this as a "feature" and
got lucky that the subtle build errors it can cause did not occur.
Therefore we need a policy to deal with the case more gracefully.
See issue #9173.
