Logic error in CMakeLists.txt when setting HAS_MMG and HAS_PARMMG

[mohrmarc]

Hi,

I detected an issue with the optional MMG dependency in the main CMakeList.txt file. This can lead to a broken elmerf90 script.
Running CMake with -DWITH_MMG=ON, but not having mmg or parmmg installed, does not set

• HAS_MMG
• HAS_PARMMG

Consequently text replacement of these in the elmerf90 template just inserts an empty string and we get lines like this:

if test  = "TRUE"; then
    MMGLIBDIR="-L"
    MMGINCLUDE="-IMMG_INCLUDE_DIR-NOTFOUND"
    printf "with MMG\n"
else
    MMGLIBDIR=""
    MMGINCLUDE=""
fi

if test  = "TRUE"; then
    PARMMGLIBDIR="-L"
    PARMMGINCLUDE="-I"
    printf "with ParMMG\n"

Now one might of course argue, that configuring with the option turned on is a bad idea, if the dependency is not installed. However, when no parallel version of mmg is installed, we still get a broken elmerf90 script, since HAS_PARMMG is not set to FALSE, when we run with

-DWITH_MMG:BOOL=TRUE   -DMMG_LIBRARY=<path-to-libmmg.so> -DMMG_INCLUDE_DIR=<path-to-include>

we still get a broken elmerf90

if test TRUE = "TRUE"; then
    MMGLIBDIR="-L/opt/software/elmerfem/2025-09-26_Installation/dependencies/local/lib"
    MMGINCLUDE="-I/opt/software/elmerfem/2025-09-26_Installation/dependencies/local/include"
    printf "with MMG\n"
else
    MMGLIBDIR=""
    MMGINCLUDE=""
fi

if test  = "TRUE"; then
    PARMMGLIBDIR="-L"
    PARMMGINCLUDE="-I"

IMHO this could be easily fixed by setting the two variables in the corresponding else branches of IF(MMG_FOUND) and IF(PARMMG_FOUND) to FALSE.

[mohrmarc]

Oh, and additionally one would need to set HAS_PARMG to FALSE also in the else branch of IF (WITH_PARMMG) due to the nesting of this inside IF (WITH_MMG) . Otherwise explicitely setting -DWITH_MMG=ON -DWITH_PARMMG=OFF will not work correctly.