PETSC_VERSION not set when cmake run second time

[floli]

Hello,

I have

find_package(PETSc 3.6 REQUIRED)
add_definitions(-DPETSC_MAJOR=${PETSC_VERSION_MAJOR} -DPETSC_MINOR=${PETSC_VERSION_MINOR})
message("PETSC VERSION: " ${PETSC_VERSION} )
message("PETSC VERSION: " ${PETSC_VERSION_MAJOR} " . " ${PETSC_VERSION_MINOR} )

To use some conditional compiling based on the PETSc version. (if there is a better way, let me know please!)

It works fine when cmake is ran on an empty directory:

% cmake ../..
[...]
-- petsc_lib_dir /home/florian/software/petsc/arch-linux2-c-debug/lib
-- Recognized PETSc install with single library for all packages
-- Performing Test MULTIPASS_TEST_1_petsc_works_minimal
-- Performing Test MULTIPASS_TEST_1_petsc_works_minimal - Failed
-- Performing Test MULTIPASS_TEST_2_petsc_works_allincludes
-- Performing Test MULTIPASS_TEST_2_petsc_works_allincludes - Success
-- PETSc requires extra include paths, but links correctly with only interface libraries.  This is an unexpected configuration (but it seems to work fine).
-- Found PETSc: /home/florian/software/petsc/include;/home/florian/software/petsc/arch-linux2-c-debug/include;/opt/mpich/include (found suitable version "3.8.4", minimum required is "3.6")
PETSC VERSION: 3.8.4
PETSC VERSION: 3 . 8

The define is also set correctly. But when I run the same command a second time

% cmake ../..
-- Build configuration: Debug
-- Special platform settings: none
-- Found PETSc: /home/florian/software/petsc/include;/home/florian/software/petsc/arch-linux2-c-debug/include;/opt/mpich/include (Required is at least version "3.6")
PETSC VERSION:
PETSC VERSION:  .

The values are empty. Also the defines for the following make are set to empty values.

Not really sure, if that is a problem of my config, or cmake or the module...

Thanks!

[jedbrown]

Either petsc_get_version needs to be cached (and cleared if the wrong PETSc was found) or it needs to be called when petsc_config_current. You could work around it by caching the variable on your end. I'm sorry, but I haven't used this module in several years and don't have time to test or investigate whether recommended practice has changed. I'm happy to review and merge PRs.

[floli]

Applying that fix I get:

CMake Error at tools/cmake-modules/FindPETSc.cmake:71 (set):
  set given invalid arguments for CACHE mode.
Call Stack (most recent call first):
  tools/cmake-modules/FindPETSc.cmake:144 (petsc_get_version)
  CMakeLists.txt:32 (find_package)


-- petsc_lib_dir /home/florian/software/petsc/arch-linux2-c-debug/lib
-- Recognized PETSc install with single library for all packages
-- Performing Test MULTIPASS_TEST_1_petsc_works_minimal
-- Performing Test MULTIPASS_TEST_1_petsc_works_minimal - Failed
-- Performing Test MULTIPASS_TEST_2_petsc_works_allincludes
-- Performing Test MULTIPASS_TEST_2_petsc_works_allincludes - Failed
-- Performing Test MULTIPASS_TEST_3_petsc_works_alllibraries
-- Performing Test MULTIPASS_TEST_3_petsc_works_alllibraries - Failed
-- Performing Test MULTIPASS_TEST_4_petsc_works_all
-- Performing Test MULTIPASS_TEST_4_petsc_works_all - Failed
-- PETSc could not be used, maybe the install is broken.
CMake Error at tools/cmake-modules/FindPETSc.cmake:327 (if):
  if given arguments:

    "VERSION_LESS" "3.1"

  Unknown arguments specified
Call Stack (most recent call first):
  CMakeLists.txt:32 (find_package)


-- Configuring incomplete, errors occurred!

CMake 3.10.3

I will try to investigate myself, but I am also open to any input.