cmake: fix a nasty bug in our CMake files

before adding a potentially empty list of targets or dependencies, we
first have to test on the length of the list;
this finally closes #131 (we really have to do these checks)

Author: torbjoernk

CMakeLists.txt

@@ -107,6 +107,7 @@ set(3rdparty_DEPENDEND_LIBS)
 set(pfasst_INCLUDES)
 set(pfasst_DEPENDEND_LIBS)
 set(pfasst_DEPENDEND_TARGETS)
+set(pfasst_TESTS_DEPENDEND_TARGETS)
 
 if(pfasst_BUILD_TESTS)
     enable_testing()
@@ -126,6 +127,10 @@ message(STATUS "Configuring 3rd party libraries")
 #  - FFTW_LIBRARIES (if pfasst_BUILD_EXAMPLES)
 add_subdirectory(3rdparty)
 
+list(LENGTH pfasst_DEPENDEND_LIBS pfasst_NUM_DEPENDEND_LIBS)
+list(LENGTH pfasst_DEPENDEND_TARGETS pfasst_NUM_DEPENDEND_TARGETS)
+list(LENGTH pfasst_TESTS_DEPENDEND_TARGETS pfasst_TESTS_NUM_DEPENDEND_TARGETS)
+
 message(STATUS "********************************************************************************")
 message(STATUS "Configuring sources")
 set(WARNING_COMMENT "/*\n * DO NOT ALTER THIS FILE\n *\n * It will get rewritten on CMake's next run\n *\n */")

examples/advection_diffusion/CMakeLists.txt

@@ -29,7 +29,10 @@ set(all_advec_examples
 foreach(example ${all_advec_examples})
     add_executable(${example} ${CMAKE_CURRENT_SOURCE_DIR}/${example}.cpp)
     if(NOT FFTW_FOUND)
-        add_dependencies(${example} ${pfasst_DEPENDEND_TARGETS} fftw3)
+        add_dependencies(${example} fftw3)
+    endif()
+    if(${pfasst_NUM_DEPENDEND_TARGETS} GREATER 0)
+        add_dependencies(${example} ${pfasst_DEPENDEND_TARGETS})
     endif()
     target_link_libraries(${example}
         ${3rdparty_DEPENDEND_LIBS}

examples/scalar/CMakeLists.txt

@@ -12,7 +12,7 @@ set(scalar_examples
 
 foreach(example ${scalar_examples})
     add_executable(${example} ${CMAKE_CURRENT_SOURCE_DIR}/${example}.cpp)
-    if(${pfasst_DEPENDEND_TARGETS})
+    if(${pfasst_NUM_DEPENDEND_TARGETS} GREATER 0)
         add_dependencies(${example} ${pfasst_DEPENDEND_TARGETS})
     endif()
     target_link_libraries(${example}

examples/vanderpol/CMakeLists.txt

@@ -12,7 +12,7 @@ set(vanderpol_examples
 
 foreach(example ${vanderpol_examples})
     add_executable(${example} ${CMAKE_CURRENT_SOURCE_DIR}/${example}.cpp)
-    if(${pfasst_DEPENDEND_TARGETS})
+    if(${pfasst_NUM_DEPENDEND_TARGETS} GREATER 0)
         add_dependencies(${example} ${pfasst_DEPENDEND_TARGETS})
     endif()
     target_link_libraries(${example}

tests/CMakeLists.txt

@@ -14,7 +14,12 @@ set(TESTS
 foreach(test ${TESTS})
     message(STATUS "  ${test}")
     add_executable(${test} ${test}.cpp)
-    add_dependencies(${test} ${pfasst_DEPENDEND_TARGETS} ${pfasst_TESTS_DEPENDEND_TARGETS})
+    if(${pfasst_NUM_DEPENDEND_TARGETS} GREATER 0)
+        add_dependencies(${test} ${pfasst_DEPENDEND_TARGETS})
+    endif()
+    if(${pfasst_TESTS_NUM_DEPENDEND_TARGETS} GREATER 0)
+        add_dependencies(${test} ${pfasst_TESTS_DEPENDEND_TARGETS})
+    endif()
     target_link_libraries(${test}
         ${3rdparty_DEPENDEND_LIBS}
         ${TESTS_3rdparty_DEPENDEND_LIBS}

tests/examples/advection_diffusion/CMakeLists.txt

@@ -20,9 +20,13 @@ foreach(test ${TESTS})
     message(STATUS "  ${test}")
     add_executable(${test} ${test}.cpp)
     if(NOT FFTW_FOUND)
-      add_dependencies(${test} ${pfasst_DEPENDEND_TARGETS} ${pfasst_TESTS_DEPENDEND_TARGETS} fftw3)
-    else()
-        add_dependencies(${test} ${pfasst_DEPENDEND_TARGETS} ${pfasst_TESTS_DEPENDEND_TARGETS})
+      add_dependencies(${test} fftw3)
+    endif()
+    if(${pfasst_NUM_DEPENDEND_TARGETS} GREATER 0)
+        add_dependencies(${test} ${pfasst_DEPENDEND_TARGETS})
+    endif()
+    if(${pfasst_TESTS_NUM_DEPENDEND_TARGETS} GREATER 0)
+        add_dependencies(${test} ${pfasst_TESTS_DEPENDEND_TARGETS})
     endif()
     target_link_libraries(${test}
         ${3rdparty_DEPENDEND_LIBS}
@@ -47,9 +51,13 @@ if(${pfasst_WITH_MPI})
         message(STATUS "  ${test}")
         add_executable(${test} ${test}.cpp)
         if(NOT FFTW_FOUND)
-          add_dependencies(${test} ${pfasst_DEPENDEND_TARGETS} ${pfasst_TESTS_DEPENDEND_TARGETS} fftw3)
-        else()
-            add_dependencies(${test} ${pfasst_DEPENDEND_TARGETS} ${pfasst_TESTS_DEPENDEND_TARGETS})
+          add_dependencies(${test} fftw3)
+        endif()
+        if(${pfasst_NUM_DEPENDEND_TARGETS} GREATER 0)
+            add_dependencies(${test} ${pfasst_DEPENDEND_TARGETS})
+        endif()
+        if(${pfasst_TESTS_NUM_DEPENDEND_TARGETS} GREATER 0)
+            add_dependencies(${test} ${pfasst_TESTS_DEPENDEND_TARGETS})
         endif()
         if(MPI_COMPILE_FLAGS)
             if(pfasst_WITH_GCC_PROF AND ${CMAKE_CXX_COMPILER_ID} MATCHES GNU)

tests/examples/boris/CMakeLists.txt

@@ -13,7 +13,12 @@ set(TESTS
 foreach(test ${TESTS})
     message(STATUS "  ${test}")
     add_executable(${test} ${test}.cpp)
-    add_dependencies(${test} ${pfasst_DEPENDEND_TARGETS} ${pfasst_TESTS_DEPENDEND_TARGETS})
+    if(${pfasst_NUM_DEPENDEND_TARGETS} GREATER 0)
+        add_dependencies(${test} ${pfasst_DEPENDEND_TARGETS})
+    endif()
+    if(${pfasst_TESTS_NUM_DEPENDEND_TARGETS} GREATER 0)
+        add_dependencies(${test} ${pfasst_TESTS_DEPENDEND_TARGETS})
+    endif()
     target_link_libraries(${test}
         ${3rdparty_DEPENDEND_LIBS}
         ${TESTS_3rdparty_DEPENDEND_LIBS}

tests/examples/scalar/CMakeLists.txt

@@ -13,7 +13,12 @@ set(TESTS
 foreach(test ${TESTS})
     message(STATUS "  ${test}")
     add_executable(${test} ${test}.cpp)
-    add_dependencies(${test} ${pfasst_DEPENDEND_TARGETS} ${pfasst_TESTS_DEPENDEND_TARGETS})
+    if(${pfasst_NUM_DEPENDEND_TARGETS} GREATER 0)
+        add_dependencies(${test} ${pfasst_DEPENDEND_TARGETS})
+    endif()
+    if(${pfasst_TESTS_NUM_DEPENDEND_TARGETS} GREATER 0)
+        add_dependencies(${test} ${pfasst_TESTS_DEPENDEND_TARGETS})
+    endif()
     target_link_libraries(${test}
         ${3rdparty_DEPENDEND_LIBS}
         ${TESTS_3rdparty_DEPENDEND_LIBS}

tests/examples/vanderpol/CMakeLists.txt

@@ -12,7 +12,12 @@ set(TESTS
 foreach(test ${TESTS})
     message(STATUS "  ${test}")
     add_executable(${test} ${test}.cpp)
-    add_dependencies(${test} ${pfasst_DEPENDEND_TARGETS} ${pfasst_TESTS_DEPENDEND_TARGETS})
+    if(${pfasst_NUM_DEPENDEND_TARGETS} GREATER 0)
+        add_dependencies(${test} ${pfasst_DEPENDEND_TARGETS})
+    endif()
+    if(${pfasst_TESTS_NUM_DEPENDEND_TARGETS} GREATER 0)
+        add_dependencies(${test} ${pfasst_TESTS_DEPENDEND_TARGETS})
+    endif()
     target_link_libraries(${test}
         ${3rdparty_DEPENDEND_LIBS}
         ${TESTS_3rdparty_DEPENDEND_LIBS}