SQUASH AGAINST: Change to find_package(Python3), set Python3_EXECUTAB…

…LE to PYTHON_EXECUTABLE (TriBITSPub#610)

NOTE: This passes the unit tests for tribits_find_python_interp() but not all
of the TriBITS tests, yet.  These changes need to be propagated across the rest
of TriBITS.

test/core/CMakeLists.txt

@@ -49,7 +49,7 @@ tribits_add_advanced_test( TestingFunctionMacro_UnitTests
       -D${PROJECT_NAME}_TRIBITS_DIR=${${PROJECT_NAME}_TRIBITS_DIR}
       -P "${CMAKE_CURRENT_SOURCE_DIR}/TestingFunctionMacro_UnitTests.cmake"
     PASS_REGULAR_EXPRESSION_ALL
-      "Final UnitTests Result: num_run = 720"
+      "Final UnitTests Result: num_run = 724"
       "Final UnitTests Result: PASSED"
   )
 

test/core/TestingFunctionMacro_UnitTests.cmake

@@ -157,6 +157,8 @@ function(unittest_tribits_create_reverse_list)
 endfunction()
 
 
+##########################################################################################
+
 function(unittest_tribits_find_python_interp)
 
   message("\n***")
@@ -166,55 +168,107 @@ function(unittest_tribits_find_python_interp)
   set(MESSAGE_WRAPPER_UNIT_TEST_MODE  TRUE)
   set(TRIBITS_FIND_PYTHON_UNITTEST  TRUE)
 
+  tribits_find_python_interp_uses_python_false()
+  tribits_find_python_interp_uses_python_empty()
+  tribits_find_python_interp_uses_python_true()
+  tribits_find_python_interp_requires_python_true()
+  tribits_find_python_interp_find_version_too_low()
+  tribits_find_python_interp_find_version_higher()
+  tribits_find_python_interp_python_executable_backward_compatible()
+
+endfunction()
+
+
+function(tribits_find_python_interp_uses_python_false)
   message("tribits_find_python_interp(): ${PROJECT_NAME}_USES_PYTHON=FALSE")
   set(${PROJECT_NAME}_USES_PYTHON  FALSE)
   global_set(MESSAGE_WRAPPER_INPUT)
   tribits_find_python_interp()
   unittest_compare_const(MESSAGE_WRAPPER_INPUT
     "-- ;NOTE: Skipping check for Python because; ${PROJECT_NAME}_USES_PYTHON='FALSE'")
-  unittest_compare_const(FIND_PythonInterp_ARGS
+  unittest_compare_const(FIND_Python3_ARGS
     "")
+endfunction()
 
-  message("tribits_find_python_interp(): ${PROJECT_NAME}_USES_PYTHON=")
-  global_set(MESSAGE_WRAPPER_INPUT)
-  set(${PROJECT_NAME}_USES_PYTHON)
-  set(PYTHON_EXECUTABLE_UNITTEST_VAL /path/to/python2.4)
+
+function(tribits_find_python_interp_uses_python_empty)
+  message("tribits_find_python_interp(): ${PROJECT_NAME}_USES_PYTHON=''")
+  global_set(MESSAGE_WRAPPER_INPUT "")
+  set(${PROJECT_NAME}_USES_PYTHON "")
+  set(Python3_EXECUTABLE_UNITTEST_VAL /path/to/python3.8)
   tribits_find_python_interp()
   unittest_compare_const(MESSAGE_WRAPPER_INPUT
-    "-- ;Python3_EXECUTABLE='/path/to/python2.4'")
+    "-- ;Python3_EXECUTABLE='/path/to/python3.8'")
+endfunction()
 
+
+function(tribits_find_python_interp_uses_python_true)
   message("tribits_find_python_interp(): ${PROJECT_NAME}_USES_PYTHON=TRUE")
   global_set(MESSAGE_WRAPPER_INPUT)
   set(${PROJECT_NAME}_USES_PYTHON TRUE)
-  global_set(PYTHON_EXECUTABLE_UNITTEST_VAL /path/to/python2.4)
+  global_set(Python3_EXECUTABLE_UNITTEST_VAL /path/to/python3.8)
   tribits_find_python_interp()
   unittest_compare_const(MESSAGE_WRAPPER_INPUT
-    "-- ;Python3_EXECUTABLE='/path/to/python2.4'")
-  unittest_compare_const(FIND_PythonInterp_ARGS
-    "PythonInterp")
+    "-- ;Python3_EXECUTABLE='/path/to/python3.8'")
+  unittest_compare_const(FIND_Python3_ARGS
+    "Python3;3.8")
+endfunction()
 
+
+function(tribits_find_python_interp_requires_python_true)
   message("tribits_find_python_interp(): ${PROJECT_NAME}_REQUIRES_PYTHON=TRUE")
   global_set(MESSAGE_WRAPPER_INPUT)
   set(${PROJECT_NAME}_USES_PYTHON FALSE)
   set(${PROJECT_NAME}_REQUIRES_PYTHON TRUE)
-  set(PYTHON_EXECUTABLE_UNITTEST_VAL /path/to/python2.4)
+  set(Python3_EXECUTABLE_UNITTEST_VAL /path/to/python3.8)
   tribits_find_python_interp()
   unittest_compare_const(MESSAGE_WRAPPER_INPUT
-    "-- ;Python3_EXECUTABLE='/path/to/python2.4'")
-  unittest_compare_const(FIND_PythonInterp_ARGS
-    "PythonInterp;REQUIRED")
+    "-- ;Python3_EXECUTABLE='/path/to/python3.8'")
+  unittest_compare_const(FIND_Python3_ARGS
+    "Python3;3.8;REQUIRED")
+endfunction()
+
 
-  message("tribits_find_python_interp(): PythonInterp_FIND_VERSION=2.3")
+function(tribits_find_python_interp_find_version_too_low)
+  message("tribits_find_python_interp(): ${PROJECT_NAME}_Python3_FIND_VERSION=3.7 (too low)")
   global_set(MESSAGE_WRAPPER_INPUT)
-  set(PythonInterp_FIND_VERSION 2.3)
-  set(PYTHON_EXECUTABLE_UNITTEST_VAL /dummy)
+  set(${PROJECT_NAME}_Python3_FIND_VERSION 3.7)
+  set(Python3_EXECUTABLE_UNITTEST_VAL /dummy)
   tribits_find_python_interp()
   unittest_compare_const(MESSAGE_WRAPPER_INPUT
-    "FATAL_ERROR;Error,; PythonInterp_FIND_VERSION=2.3 < 2.6; is not allowed!;-- ;Python3_EXECUTABLE='/dummy'")
+    "FATAL_ERROR;Error,; ${PROJECT_NAME}_Python3_FIND_VERSION=3.7 < 3.8; is not allowed!;-- ;Python3_EXECUTABLE='/dummy'")
+endfunction()
+
+
+function(tribits_find_python_interp_find_version_higher)
+  message("tribits_find_python_interp(): ${PROJECT_NAME}_Python3_FIND_VERSION=3.11")
+  global_set(MESSAGE_WRAPPER_INPUT)
+  set(${PROJECT_NAME}_REQUIRES_PYTHON TRUE)
+  set(${PROJECT_NAME}_Python3_FIND_VERSION 3.11)
+  set(Python3_EXECUTABLE_UNITTEST_VAL /path/to/python3.11)
+  tribits_find_python_interp()
+  unittest_compare_const(MESSAGE_WRAPPER_INPUT
+    "-- ;Python3_EXECUTABLE='/path/to/python3.11'")
+  unittest_compare_const(FIND_Python3_ARGS
+    "Python3;3.11;REQUIRED")
+endfunction()
+
 
+function(tribits_find_python_interp_python_executable_backward_compatible)
+  message("tribits_find_python_interp(): PYTHON_EXECUTABLE backward compatibility")
+  global_set(MESSAGE_WRAPPER_INPUT)
+  set(PYTHON_EXECUTABLE /path/to/python3.10.2)
+  tribits_find_python_interp()
+  unittest_compare_const(MESSAGE_WRAPPER_INPUT
+    "DEPRECATION;Python3_EXECUTABLE being set by default to PYTHON_EXECUTABLE = '/path/to/python3.10.2' is deprecated!;\n\nNOTE: To Make these warnings go away, set -D; TRIBITS_HANDLE_TRIBITS_DEPRECATED_CODE=IGNORE (see the build reference guide).;-- ;Python3_EXECUTABLE='/path/to/python3.10.2'")
+  unittest_compare_const(FIND_Python3_ARGS
+    "Python3;3.8")
 endfunction()
 
 
+##########################################################################################
+
+
 function(unittest_tribits_standardize_abs_paths)
 
   message("\n***")
@@ -4844,4 +4898,4 @@ message("*** Determine final result of all unit tests")
 message("***\n")
 
 # Pass in the number of expected tests that must pass!
-unittest_final_result(720)
+unittest_final_result(724)

tribits/core/package_arch/TribitsFindPythonInterp.cmake

@@ -7,26 +7,55 @@
 # *****************************************************************************
 # @HEADER
 
+
 # Find Python executable which is needed for dependency file building
 macro(tribits_find_python)
+  # Get minimum version of Python to find
+  set(${PROJECT_NAME}_Python3_FIND_VERSION_MIN "3.8")
+  if ("${${PROJECT_NAME}_Python3_FIND_VERSION_DEFAULT}" STREQUAL "")
+    set(${PROJECT_NAME}_Python3_FIND_VERSION_DEFAULT
+      "${${PROJECT_NAME}_Python3_FIND_VERSION_MIN}")
+  endif()
+  advanced_set(${PROJECT_NAME}_Python3_FIND_VERSION
+    ${${PROJECT_NAME}_Python3_FIND_VERSION_DEFAULT}
+    CACHE  STRING
+    "Default version of Python to find (must be ${${PROJECT_NAME}_Python3_FIND_VERSION_DEFAULT} or greater")
+  if (${PROJECT_NAME}_Python3_FIND_VERSION  VERSION_LESS
+      "${${PROJECT_NAME}_Python3_FIND_VERSION_MIN}"
+    )
+    message_wrapper(FATAL_ERROR  "Error,"
+      " ${PROJECT_NAME}_Python3_FIND_VERSION=${${PROJECT_NAME}_Python3_FIND_VERSION} < ${${PROJECT_NAME}_Python3_FIND_VERSION_MIN}"
+      " is not allowed!" )
+  endif()
+  # Provide backward compatibility for user setting PYTHON_EXECUTABLE
   if ((NOT "${PYTHON_EXECUTABLE}" STREQUAL "") AND ("${Python3_EXECUTABLE}" STREQUAL ""))
     tribits_deprecated("Python3_EXECUTABLE being set by default to PYTHON_EXECUTABLE = '${PYTHON_EXECUTABLE}' is deprecated!")
     set(Python3_EXECUTABLE "${PYTHON_EXECUTABLE}" CACHE FILEPATH
       "Set by default to PYTHON_EXECUTABLE!")
   endif()
+  # Find Python
   if (${PROJECT_NAME}_REQUIRES_PYTHON)
     set(Python3_REQUIRED_ARG "REQUIRED")
   else()
     set(Python3_REQUIRED_ARG "")
   endif()
-  if (TRIBITS_FIND_PYTHON_UNITTEST)
-    set(Python3_EXECUTABLE  ${PYTHON_EXECUTABLE_UNITTEST_VAL})
+  set(FIND_Python3_ARGS
+    Python3 ${${PROJECT_NAME}_Python3_FIND_VERSION} ${Python3_REQUIRED_ARG})
+  if(NOT "${Python3_EXECUTABLE}" STREQUAL "")
+    # Already set, don't need to call anything!
+  elseif (TRIBITS_FIND_PYTHON_UNITTEST)
+    set(Python3_EXECUTABLE  ${Python3_EXECUTABLE_UNITTEST_VAL})
   else()
-    find_package(Python3 ${Python3_REQUIRED_ARG})
+    find_package(${FIND_Python3_ARGS})
   endif()
 endmacro()
 
 
+# Select the minimum version of Python
+
+
+
+
 # TriBITS Wrapper for finding Python (or not) for a TriBITS project.
 macro(tribits_find_python_interp)
   if (${PROJECT_NAME}_REQUIRES_PYTHON)

tribits/doc/guides/TribitsGuidesBody.rst

@@ -7003,17 +7003,16 @@ Python Support
 
 TriBITS Core does not require anything other than raw CMake.  However, Python
 Utils, TriBITS CI Support, and other extended TriBITS components require
-Python.  These extra TriBITS tools only require Python 2.7+ (and 3.x).  By
-default, when a TriBITS project starts to configure using CMake, it will try
-to find Python 2.7+ on the system (see `Full Processing of TriBITS Project
-Files`_).  If Python is found, it will set the global cache variable
-``Python3_EXECUTABLE``.  If it is not found, then it will print a warning and
-``Python3_EXECUTABLE`` will be empty.  With this default behavior, if Python is
-found, then the TriBITS project can use it.  Otherwise, it can do without it.
+Python.  These extra TriBITS tools only require Python 3.8+.  By default, when
+a TriBITS project starts to configure using CMake, it will try to find Python
+3.8+ on the system (see `Full Processing of TriBITS Project Files`_).  If
+Python is found, it will set the global cache variable ``Python3_EXECUTABLE``.
+If it is not found, then it will print a warning and ``Python3_EXECUTABLE``
+will be empty.  With this default behavior, if Python is found, then the
+TriBITS project can use it.  Otherwise, it can do without it.
 
 While the default behavior for finding Python described above is useful for
-many TriBITS project (such as Trilinos), some TriBITS projects need different
-behavior such as:
+many TriBITS projects, some TriBITS projects need different behavior such as:
 
 1. The TriBITS project may not ever use Python so there is no need to look for
    it at all.  In this case, the TriBITS project would set
@@ -7023,11 +7022,12 @@ behavior such as:
    can't be found.  In this case, the TriBITS project would set
    `${PROJECT_NAME}_REQUIRES_PYTHON`_ to ``TRUE``.
 
-3. Some TriBITS projects may require a version of Python more recent than 2.7.
-   In this case, the TriBITS project would set `PythonInterp_FIND_VERSION`_ to
-   some value higher than ``2.7``.  For example, may newer systems have only
-   Python 3.5.2 or higher versions installed by default and projects developed
-   on such a system typically requires this version or higher.
+3. Some TriBITS projects may require a version of Python more recent than 3.8.
+   In this case, the TriBITS project would set
+   `${PROJECT_NAME}_Python3_FIND_VERSION`_ to some value higher than ``3.8``.
+   For example, may newer systems have higher versions of Python installed by
+   default, and projects developed on such a system typically require this
+   version or higher.
 
 
 Project-Specific Build Reference