Commit Graph

20 Commits

Author SHA1 Message Date
Brad King c4275592a8 Modules: Include builtin FindPackageHandleStandardArgs directly
The FindPackageHandleStandardArgs module was originally created outside
of CMake.  It was added for CMake 2.6.0 by commit e118a627 (add a macro
FIND_PACKAGE_HANDLE_STANDARD_ARGS..., 2007-07-18).  However, it also
proliferated into a number of other projects that at the time required
only CMake 2.4 and thus could not depend on CMake to provide the module.
CMake's own find modules started using the module in commit b5f656e0
(use the new FIND_PACKAGE_HANDLE_STANDARD_ARGS in some of the FindXXX
modules..., 2007-07-18).

Then commit d358cf5c (add 2nd, more powerful mode to
find_package_handle_standard_args, 2010-07-29) added a new feature to
the interface of the module that was fully optional and backward
compatible with all existing users of the module.  Later commit 5f183caa
(FindZLIB: use the FPHSA version mode, 2010-08-04) and others shortly
thereafter started using the new interface in CMake's own find modules.
This change was also backward compatible because it was only an
implementation detail within each module.

Unforutnately these changes introduced a problem for projects that still
have an old copy of FindPackageHandleStandardArgs in CMAKE_MODULE_PATH.
When any such project uses one of CMake's builtin find modules the line

  include(FindPackageHandleStandardArgs)

loads the copy from the project which does not have the new interface!
Then the including find module tries to use the new interface with the
old module and fails.

Whether this breakage can be considered a backward incompatible change
in CMake is debatable.  The situation is analagous to copying a standard
library header from one version of a compiler into a project and then
observing problems when the next version of the compiler reports errors
in its other headers that depend on its new version of the original
header.  Nevertheless it is a change to CMake that causes problems for
projects that worked with previous versions.

This problem was discovered during the 2.8.3 release candidate cycle.
It is an instance of a more general problem with projects that provide
their own versions of CMake modules when other CMake modules depend on
them.  At the time we resolved this instance of the problem with commit
b0118402 (Use absolute path to FindPackageHandleStandardArgs.cmake
everywhere, 2010-09-28) for the 2.8.3 release.

In order to address the more general problem we introduced policy
CMP0017 in commit db44848f (Prefer files from CMAKE_ROOT when including
from CMAKE_ROOT, 2010-11-17).  That change was followed by commit
ce28737c (Remove usage of CMAKE_CURRENT_LIST_DIR now that we have
CMP0017, 2010-12-20) which reverted the original workaround in favor of
using the policy.  However, existing project releases do not set the
policy behavior to NEW and therefore still exhibit the problem.

We introduced in commit a364daf1 (Allow users to specify defaults for
unset policies, 2011-01-03) an option for users to build existing
projects by adding -DCMAKE_POLICY_DEFAULT_CMP0017=NEW to the command
line.  Unfortunately this solution still does not allow such projects to
build out of the box, and there is no good way to suggest the use of the
new option.

The only remaining solution to keep existing projects that exhibit this
problem building is to restore the change originally made in commit
b0118402 (Use absolute path to FindPackageHandleStandardArgs.cmake
everywhere, 2010-09-28).  This also avoids policy CMP0017 warnings for
this particular instance of the problem the policy addresses.
2011-01-20 10:56:49 -05:00
Alex Neundorf ce28737c93 Remove usage of CMAKE_CURRENT_LIST_DIR now that we have CMP0017
This puts the new search behaviour for included files in action, i.e.
now when a file from Modules/ include()s another file, it also gets the
one from Modules/ included, i.e. the one it expects.

Alex
2011-01-04 08:20:08 -05:00
Alex Neundorf b01184022b Use absolute path to FindPackageHandleStandardArgs.cmake everywhere
This is to avoid getting an (older) copy of FPHSA.cmake which is
e.g. installed with KDE 4.5.0 and 4.5.1.

Alex
2010-09-28 22:30:31 +02:00
Todd Gamblin 2cde67a781 Modules: Fix spelling 'To distributed' -> 'To distribute' 2010-08-09 08:48:31 -04:00
Brad King c4bb9c9d42 Convert CMake find-modules to BSD License
This adds copyright/license notification blocks CMake's find-modules.
Many of the modules had no notices at all.  Some had notices referring
to the BSD license already.  This commit normalizes existing notices and
adds missing notices.
2009-09-28 11:45:50 -04:00
Bill Hoffman d34068e2d4 BUG: #7416 fix error when jpeg is not found 2008-07-29 16:41:29 -04:00
Alexander Neundorf 13db5b578b ENH: add second failure message parameter to
FIND_PACKAGE_HANDLE_STANDARD_ARGS(), so cmake modules can specify their own
better failure messages. If the default is ok use "DEFAULT_MSG".
Do this also for FindBoost.cmake (#5349)

Alex
2007-07-23 09:49:52 -04:00
Alexander Neundorf b5f656e0de ENH: use the new FIND_PACKAGE_HANDLE_STANDARD_ARGS in some of the FindXXX
modules, remove some of the extra search paths which are also searched by
default

Alex
2007-07-18 13:56:45 -04:00
Alexander Neundorf 60988dd8a2 ENH: honor REQUIRED flag
Alex
2006-05-11 18:32:40 -04:00
Brad King 64cb554397 ENH: Removing platform-specific name hacks now that FIND_LIBRARY handles it. 2006-02-09 15:08:16 -05:00
Brad King ef88c8cbc8 ENH: Added names for gnuwin32 library versions. 2006-02-09 12:04:25 -05:00
Ken Martin d2689c95a1 ENH: some style fixes for the book 2005-12-15 10:41:19 -05:00
Bill Hoffman b7fa820118 ENH: add documentation support for modules 2005-12-14 13:51:08 -05:00
Bill Hoffman af59771b9b ENH: clean up some stuff 2005-09-08 11:38:55 -04:00
Brad King 290ffc01b6 ENH: Removing extra 64-bit search paths. They are now constructed automatically from the paths listed. 2005-04-07 14:27:01 -04:00
Brad King 76f9050026 ENH: Adding support for 64-bit library paths. Contributed by Peter Vanroose. 2005-04-07 13:46:02 -04:00
Ian Scott 0b288b6121 Fixed mistake in comments
Transferred OPENGL finding logic in from VXL
Added Some backwards compatibility with CMake1.4
2002-09-03 06:10:06 -04:00
Ian Scott 5f60153d2f Add helpful message for QT Windows users
Add FindZLib in new format
Move FindJPEG and FINDWGET over to new scheme
2002-09-02 12:05:40 -04:00
Bill Hoffman f07ee5b817 ENH: change find library and find program to look for more than one name 2001-05-09 14:53:32 -04:00
Geoffrey Cross 7bf828d132 INCLUDE these to find the relevant libraries 2001-05-04 11:35:47 -04:00