Repository navigation
ITK_INSTALL_*_DIR are assumed relative to CMAKE_INSTALL_PREFIX; absolute values yield wrong paths #6896
Description
Activity
Concrete measurement of the breakage, from PR #6894.
Configuring
mainwith-DCMAKE_INSTALL_LIBDIR=/usr/lib64(whichGNUInstallDirspermits) exits 0, but the exported configuration is wrong:ITKCommon_RUNTIME_LIBRARY_DIRS = "<build-dir>//usr/lib64"That is
CMake/ITKModuleMacros.cmake:542joining the build directory to an already-absolute path, with the doubled slash, pointing where no library is installed. CMake also writes the generated package files into<build-dir>/usr/lib64/.So the layout is silently wrong rather than unsupported-but-working, which raises the priority of picking a policy here: either handle absolute values at every site, or reject them once, centrally, where the variables are defined.
PR #6894 now aborts at configure time when it sees an absolute value, but only from
Modules/Core/TestKernel/src/CMakeLists.txt, which is a narrow and slightly arbitrary place for a global constraint to be enforced. A check next to the defaults inCMakeLists.txt:224-236would be the better home once this is decided.Enforcing that
ITK_INSTALL_*_DIRs are relative sounds like the right thing to do.
ITK_INSTALL_RUNTIME_DIRandITK_INSTALL_LIBRARY_DIRare joined toCMAKE_INSTALL_PREFIXin several places, so an absolute value silently yields a malformed path. CMake installs an absoluteDESTINATIONoutside the prefix, so the two disagree.Where the assumption is made
CMake/ITKModuleMacros.cmake:533"\${ITK_INSTALL_PREFIX}/${ITK_INSTALL_RUNTIME_DIR}"CMake/ITKModuleMacros.cmake:542"\${ITK_INSTALL_PREFIX}/${ITK_INSTALL_LIBRARY_DIR}"Modules/Core/TestKernel/src/CMakeLists.txtitkTestDriverRPATHThe first two feed
<module>_RUNTIME_LIBRARY_DIRSin the exported configuration, so a consumer of an installed ITK inherits the wrong directories, not just the test driver.Defaults are relative (
bin, and${CMAKE_INSTALL_LIBDIR}which defaults tolib), so the supported configurations are unaffected.What support would require
Each site needs to branch on
IS_ABSOLUTEand skip the prefix join, and the exportedITKConfigwould need the same treatment so that relocation logic does not rewrite a deliberately absolute path. That is a repo-wide change to the module macros and the exported configuration, which is why it is filed separately rather than folded into a single install rule.A narrower alternative is to state in the documentation that these variables must be relative and keep the configure-time guards.
Found by an automated review on PR #6894, which added the
itkTestDriverinstall RPATH. That PR guards its own computation withIS_ABSOLUTEand fails at configure time rather than emitting a wrong RPATH; the other two sites are unguarded.