Ensure that correct python version is used for build - PYTHON_EXECUTABLE (RhBug:1598988) (rpm-software-management#1129)

* Ensure that correct python version is used for build (RhBug:1598988)
* PYTHON_DESIRED can be either "2", "3" or a path to interpreter

Author: m-blaha

CMakeLists.txt

@@ -3,23 +3,23 @@ CMAKE_MINIMUM_REQUIRED (VERSION 2.4)
 
 INCLUDE (${CMAKE_SOURCE_DIR}/VERSION.cmake)
 
-if (NOT PYTHON_DESIRED)
-    set (PYTHON_DESIRED "2")
-endif()
-
 SET( SYSCONFDIR /etc)
 SET( SYSTEMD_DIR /usr/lib/systemd/system)
 
-if (${PYTHON_DESIRED} STREQUAL "2")
-	FIND_PACKAGE (PythonInterp REQUIRED)
-else()
-	SET(Python_ADDITIONAL_VERSIONS 3.3)
-	FIND_PACKAGE(PythonLibs 3.0)
-	FIND_PACKAGE(PythonInterp 3.0 REQUIRED)
-endif()
+IF (NOT PYTHON_DESIRED)
+    FIND_PACKAGE (PythonInterp REQUIRED)
+ELSEIF (${PYTHON_DESIRED} STREQUAL "2")
+    FIND_PACKAGE (PythonInterp 2 EXACT REQUIRED)
+ELSEIF (${PYTHON_DESIRED} STREQUAL "3")
+    FIND_PACKAGE (PythonInterp 3 EXACT REQUIRED)
+ELSEIF (EXISTS ${PYTHON_DESIRED})
+    SET (PYTHON_EXECUTABLE ${PYTHON_DESIRED})
+    FIND_PACKAGE (PythonInterp REQUIRED)
+ELSE ()
+    MESSAGE (FATAL_ERROR "Invalid PYTHON_DESIRED value: " ${PYTHON_DESIRED})
+ENDIF()
 
 EXECUTE_PROCESS(COMMAND ${PYTHON_EXECUTABLE} -c "from sys import stdout; from distutils import sysconfig; stdout.write(sysconfig.get_python_lib())" OUTPUT_VARIABLE PYTHON_INSTALL_DIR)
-EXECUTE_PROCESS(COMMAND ${PYTHON_EXECUTABLE} -c "import sys; sys.stdout.write('%s.%s' % (sys.version_info.major, sys.version_info.minor))" OUTPUT_VARIABLE PYTHON_MAJOR_DOT_MINOR_VERSION)
 MESSAGE(STATUS "Python install dir is ${PYTHON_INSTALL_DIR}")
 
 ADD_SUBDIRECTORY (dnf)
@@ -30,8 +30,8 @@ ADD_SUBDIRECTORY (po)
 ENABLE_TESTING()
 ADD_SUBDIRECTORY (tests)
 
-CONFIGURE_FILE(${CMAKE_SOURCE_DIR}/bin/dnf.in ${CMAKE_SOURCE_DIR}/bin/dnf-${PYTHON_DESIRED} @ONLY)
-CONFIGURE_FILE(${CMAKE_SOURCE_DIR}/bin/dnf-automatic.in ${CMAKE_SOURCE_DIR}/bin/dnf-automatic-${PYTHON_DESIRED} @ONLY)
+CONFIGURE_FILE(${CMAKE_SOURCE_DIR}/bin/dnf.in ${CMAKE_SOURCE_DIR}/bin/dnf-${PYTHON_VERSION_MAJOR} @ONLY)
+CONFIGURE_FILE(${CMAKE_SOURCE_DIR}/bin/dnf-automatic.in ${CMAKE_SOURCE_DIR}/bin/dnf-automatic-${PYTHON_VERSION_MAJOR} @ONLY)
 CONFIGURE_FILE(${CMAKE_SOURCE_DIR}/dnf/const.py.in ${CMAKE_SOURCE_DIR}/dnf/const.py @ONLY)
 CONFIGURE_FILE(${CMAKE_SOURCE_DIR}/tests/modules/etc/dnf/repos.d/test.repo.in ${CMAKE_SOURCE_DIR}/tests/modules/etc/dnf/repos.d/test.repo @ONLY)
 CONFIGURE_FILE(${CMAKE_SOURCE_DIR}/tests/modules/etc/dnf/dnf.conf.in ${CMAKE_SOURCE_DIR}/tests/modules/etc/dnf/dnf.conf @ONLY)

bin/CMakeLists.txt

@@ -1,7 +1,2 @@
-if (${PYTHON_DESIRED} STREQUAL "2")
-    INSTALL (PROGRAMS "dnf-2" DESTINATION bin)
-    INSTALL (PROGRAMS "dnf-automatic-2" DESTINATION bin)
-else()
-    INSTALL (PROGRAMS "dnf-3" DESTINATION bin)
-    INSTALL (PROGRAMS "dnf-automatic-3" DESTINATION bin)
-endif()
+INSTALL (PROGRAMS "dnf-${PYTHON_VERSION_MAJOR}" DESTINATION bin)
+INSTALL (PROGRAMS "dnf-automatic-${PYTHON_VERSION_MAJOR}" DESTINATION bin)

dnf.spec

@@ -275,15 +275,15 @@ mkdir build-py3
 %build
 %if %{with python2}
     pushd build-py2
-    %cmake .. -DPYTHON_DESIRED:str=2
+    %cmake .. -DPYTHON_DESIRED:FILEPATH=%{__python2}
     %make_build
     make doc-man
     popd
 %endif
 
 %if %{with python3}
     pushd build-py3
-    %cmake .. -DPYTHON_DESIRED:str=3
+    %cmake .. -DPYTHON_DESIRED:FILEPATH=%{__python3}
     %make_build
     make doc-man
     popd