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.
This fixes the CMP0012 description to have a one-line summary in the
'brief' section and the rest of the explanation in the 'full' section.
It makes the warning message shorter and improves formatting of the
policy documentation, especially in the HTML pages. The convention is
already used by all other policies.
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.
Isolation of policy changes inside scripts is important for protecting
the including context. This teaches include() and find_package() to
imply a cmake_policy(PUSH) and cmake_policy(POP) around the scripts they
load, with a NO_POLICY_SCOPE option to disable the behavior. This also
creates CMake Policy CMP0011 to provide compatibility. See issue #8192.
Previously error messages produced by parsing of command argument
variable references, such as bad $KEY{VAR} syntax or a bad escape
sequence, did not provide good context information. Errors parsing
arguments inside macro invocations gave no context at all. Furthermore,
some errors such as a missing close curly "${VAR" would be reported but
build files would still be generated.
These changes teach CMake to report errors with good context information
for all command argument parsing problems. Policy CMP0010 is introduced
so that existing projects that built despite such errors will continue
to work.
In the future some policies may be set to REQUIRED_IF_USED or
REQUIRED_ALWAYS. This change clarifies the error messages users receive
when violating the requirements.
This change introduces policy CMP0008 to decide how to treat full path
libraries that do not appear to be valid library file names. Such
libraries worked by accident in the VS IDE and Xcode generators with
CMake 2.4 and below. We support them in CMake 2.6 by introducing this
policy. See policy documentation added by this change for details.
- Message for missing cmake_minimum_required is not issued
until the end of processing the top CMakeLists.txt file
- During processing a cmake_policy command may set behavior
- OLD behavior is to silently ignore the problem
- NEW behavior is to issue an error instead of a warning
- In cmake_minimum_required do not set policy version if current
CMake is too old
- In cmPolicies::ApplyPolicyVersion report error if version is too
new or cannot be parsed
- Give example code to avoid the warning
- Make explanation more consise
- Explicitly state this is for compatibility
- Issue the warning for at most one target
- Update policy CMP0000 to require use of the command
cmake_minimum_required and not cmake_policy
so there is only one way to avoid it.
- Explicitly specify the line users should add.
- Reference policy CMP0000 only at the end.
- Fix policy CMP0000 documentation to not suggest
use of the cmake_policy command.
- Policy is WARN by default so projects will build
as they did in 2.4 without user intervention
- Remove CMAKE_LINK_OLD_PATHS variable since it was
never in a release and the policy supercedes it
- Report target creation backtrace in warning message
since policy should be set by that point
- Remove CMP_0001 (no slash in target name) and restore
old CMAKE_BACKWARDS_COMPATIBILITY check for it
- Replace all checks of CMAKE_BACKWARDS_COMPATIBILITY
with cmLocalGenerator::NeedBackwardsCompatibility calls
- Create new CMP_0001 to determine whether or not
CMAKE_BACKWARDS_COMPATIBILITY is used.
(old = use, new = ignore)
- Show CMAKE_BACKWARDS_COMPATIBILITY in cache only when
CMP_0001 is set to OLD or WARN
- Update documentation of cmake_policy and cmake_minimum_required
to indicate their relationship and the 2.4 version boundary
- When no cmake policy version is set in top level makefile
implicitly call cmake_policy(VERSION 2.4) which restores
CMAKE_BACKWARDS_COMPATIBILITY and other 2.4 compatibility
- Fix tests MakeClean and Preprocess to call
cmake_policy(VERSION 2.6) because they depend on new policies
- Add cmMakefile methods IssueError and IssueWarning
- Maintain an explicit call stack in cmMakefile
- Include context/call-stack info in messages
- Nested errors now unwind the call stack
- Use new mechanism for policy warnings and errors
- Improve policy error message
- Include cmExecutionStatus pointer in call stack
so that errors deeper in the C++ stack under
a command invocation will become errors for the
command
Brad King
Ken Martin
David Cole
Bill Hoffman