Don't run compile tests unless package is found

The cmake_cxx_source_compiles() command sets internal cache vars, so they won't get overwritten on a second run. This is relevant if GTest sources are not found on system, we run the CMake configure step, install libgtest-dev, and run CMake again. Even though the package is there, internal variables prevent find_package from updating the found/not_found status. Also, pass an adequate name of the _FOUND variable to find_package_handle_standard_args(), case is relevant.
roboticslab-uc3m · Feb 19, 2018 · 6063082 · 6063082
1 parent 77d5da2
commit 6063082
Showing 1 changed file with 44 additions and 39 deletions.
diff --git a/cmake/FindGTestSources.cmake b/cmake/FindGTestSources.cmake
@@ -41,53 +41,58 @@ if(NOT GTestSources_INCLUDE_DIR)
                                        NO_CMAKE_ENVIRONMENT_PATH)
 endif()
 
-set(_cmake_include_dirs ${CMAKE_REQUIRED_INCLUDES})
+set(GTestSources_VERSION GTestSources_VERSION-NOT_FOUND)
 
-include(CheckCXXSourceCompiles)
-list(APPEND CMAKE_REQUIRED_INCLUDES ${GTestSources_INCLUDE_DIR})
+if(GTestSources_SOURCE_DIR AND GTestSources_INCLUDE_DIR)
+    set(_cmake_include_dirs ${CMAKE_REQUIRED_INCLUDES})
 
-check_cxx_source_compiles("
-        #include <gtest/gtest.h>
-        int main() {
-            typedef const char* (testing::TestInfo::*fun)() const;
-            fun f = &testing::TestInfo::type_param;
-            return 0;
-        }"
-    _gtest_compatible_1_6_0)
+    include(CheckCXXSourceCompiles)
+    list(APPEND CMAKE_REQUIRED_INCLUDES ${GTestSources_INCLUDE_DIR})
 
-check_cxx_source_compiles("
-        #include <gtest/gtest.h>
-        int main() {
-            typedef bool (testing::TestInfo::*fun)() const;
-            fun f = &testing::TestInfo::is_reportable;
-            return 0;
-        }"
-    _gtest_compatible_1_7_0)
+    check_cxx_source_compiles("
+            #include <gtest/gtest.h>
+            int main() {
+                typedef const char* (testing::TestInfo::*fun)() const;
+                fun f = &testing::TestInfo::type_param;
+                return 0;
+            }"
+        _gtest_compatible_1_6_0)
 
-check_cxx_source_compiles("
-        #include <gtest/gtest.h>
-        int main() {
-            typedef const char* (testing::TestInfo::*fun)() const;
-            fun f = &testing::TestInfo::file;
-            return 0;
-        }"
-    _gtest_compatible_1_8_0)
+    check_cxx_source_compiles("
+            #include <gtest/gtest.h>
+            int main() {
+                typedef bool (testing::TestInfo::*fun)() const;
+                fun f = &testing::TestInfo::is_reportable;
+                return 0;
+            }"
+        _gtest_compatible_1_7_0)
 
-if(_gtest_compatible_1_8_0)
-    set(GTestSources_VERSION 1.8.0)
-elseif(_gtest_compatible_1_7_0)
-    set(GTestSources_VERSION 1.7.0)
-elseif(_gtest_compatible_1_6_0)
-    set(GTestSources_VERSION 1.6.0)
-else()
-    message(STATUS "FindGTestSources.cmake reports unhandled GTest version (<1.6.0)")
-    set(GTestSources_VERSION GTestSources_VERSION-NOT_FOUND)
-endif()
+    check_cxx_source_compiles("
+            #include <gtest/gtest.h>
+            int main() {
+                typedef const char* (testing::TestInfo::*fun)() const;
+                fun f = &testing::TestInfo::file;
+                return 0;
+            }"
+        _gtest_compatible_1_8_0)
+
+    if(_gtest_compatible_1_8_0)
+        set(GTestSources_VERSION 1.8.0)
+    elseif(_gtest_compatible_1_7_0)
+        set(GTestSources_VERSION 1.7.0)
+    elseif(_gtest_compatible_1_6_0)
+        set(GTestSources_VERSION 1.6.0)
+    else()
+        message(STATUS "FindGTestSources.cmake reports unhandled GTest version (<1.6.0)")
+    endif()
 
-set(CMAKE_REQUIRED_INCLUDES "${_cmake_include_dirs}")
+    set(CMAKE_REQUIRED_INCLUDES "${_cmake_include_dirs}")
+    unset(_cmake_include_dirs)
+endif()
 
 include(FindPackageHandleStandardArgs)
-find_package_handle_standard_args(GTestSources REQUIRED_VARS GTestSources_SOURCE_DIR
+find_package_handle_standard_args(GTestSources FOUND_VAR GTestSources_FOUND
+                                               REQUIRED_VARS GTestSources_SOURCE_DIR
                                                              GTestSources_INCLUDE_DIR
                                                VERSION_VAR GTestSources_VERSION)