Merge topic 'matlab_root'

72dd680609 FindMatlab: follow CMP0074 <PackageName>_ROOT search behavior
ba74c58ca4 FindMatlab: add'l check that Matlab test version file exists

Acked-by: Kitware Robot <[email protected]>
Merge-request: !7616

Modules/FindMatlab.cmake

@@ -85,10 +85,18 @@ Module Input Variables
 Users or projects may set the following variables to configure the module
 behavior:
 
+:variable:`Matlab_ROOT <<PackageName>_ROOT>`
+  .. versionadded:: 3.25
+
+  Default value for :variable:`Matlab_ROOT_DIR`, the root of the Matlab
+  installation.
+
 :variable:`Matlab_ROOT_DIR`
-  the root of the Matlab installation.
+  The root of the Matlab installation.
+
 :variable:`MATLAB_FIND_DEBUG`
   outputs debug information
+
 :variable:`MATLAB_ADDITIONAL_VERSIONS`
   additional versions of Matlab for the automatic retrieval of the installed
   versions.
@@ -843,6 +851,15 @@ function(matlab_get_version_from_matlab_run matlab_binary_program matlab_list_ve
     endif()
   endif()
 
+  if(NOT EXISTS "${_matlab_temporary_folder}/matlabVersionLog.cmaketmp")
+    # last resort check as some HPC with "module load matlab" not enacted fail to catch in earlier checks
+    # and error CMake configure even if find_package(Matlab) is not REQUIRED
+    if(MATLAB_FIND_DEBUG)
+      message(WARNING "[MATLAB] Unable to determine the version of Matlab. The version log file does not exist.")
+    endif()
+    return()
+  endif()
+
   # if successful, read back the log
   file(READ "${_matlab_temporary_folder}/matlabVersionLog.cmaketmp" _matlab_version_from_cmd)
   file(REMOVE "${_matlab_temporary_folder}/matlabVersionLog.cmaketmp")
@@ -1572,6 +1589,13 @@ endfunction()
 # this variable will get all Matlab installations found in the current system.
 set(_matlab_possible_roots)
 
+if(NOT DEFINED Matlab_ROOT AND DEFINED ENV{Matlab_ROOT})
+  set(Matlab_ROOT $ENV{Matlab_ROOT})
+endif()
+if(DEFINED Matlab_ROOT)
+  set(Matlab_ROOT_DIR ${Matlab_ROOT})
+endif()
+
 if(Matlab_ROOT_DIR)
   # if the user specifies a possible root, we keep this one