Merge pull request #3157 from yeswalrus/fix-version-check

Fix CMake version check

cmake/protobuf-config-version.cmake.in

@@ -17,30 +17,32 @@ endif()
 
 set(PACKAGE_VERSION_COMPATIBLE TRUE) #Assume true until shown otherwise
 
-if(NOT PACKAGE_FIND_VERSION_MAJOR EQUAL "@protobuf_VERSION_MAJOR@")
-  set(PACKAGE_VERSION_COMPATIBLE FALSE)
-elseif(PACKAGE_FIND_VERSION VERSION_GREATER PACKAGE_VERSION)
-  set(PACKAGE_VERSION_COMPATIBLE FALSE)
-elseif(PACKAGE_FIND_VERSION VERSION_EQUAL PACKAGE_VERSION)
-  # Do not match prerelease versions to non-prerelease version requests.
-  if(NOT "@protobuf_VERSION_PRERELEASE@" STREQUAL "" AND PACKAGE_FIND_VERSION_PRERELEASE STREQUAL "")
-    message(AUTHOR_WARNING "To use this prerelease version of ${PACKAGE_FIND_NAME}, set ${PACKAGE_FIND_NAME}_FIND_VERSION_PRERELEASE to '@protobuf_VERSION_PRERELEASE@' or greater.")
+if(PACKAGE_FIND_VERSION) #Only perform version checks if one is given
+  if(NOT PACKAGE_FIND_VERSION_MAJOR EQUAL "@protobuf_VERSION_MAJOR@")
     set(PACKAGE_VERSION_COMPATIBLE FALSE)
-  endif()
-
-  # Not robustly SemVer compliant, but protobuf never uses '.' separated prerelease identifiers.
-  if(PACKAGE_FIND_VERSION_PRERELEASE STRGREATER "@protobuf_VERSION_PRERELEASE@")
+  elseif(PACKAGE_FIND_VERSION VERSION_GREATER PACKAGE_VERSION)
     set(PACKAGE_VERSION_COMPATIBLE FALSE)
+  elseif(PACKAGE_FIND_VERSION VERSION_EQUAL PACKAGE_VERSION)
+    # Do not match prerelease versions to non-prerelease version requests.
+      if(NOT "@protobuf_VERSION_PRERELEASE@" STREQUAL "" AND PACKAGE_FIND_VERSION_PRERELEASE STREQUAL "")
+      message(AUTHOR_WARNING "To use this prerelease version of ${PACKAGE_FIND_NAME}, set ${PACKAGE_FIND_NAME}_FIND_VERSION_PRERELEASE to '@protobuf_VERSION_PRERELEASE@' or greater.")
+      set(PACKAGE_VERSION_COMPATIBLE FALSE)
+    endif()
+
+    # Not robustly SemVer compliant, but protobuf never uses '.' separated prerelease identifiers.
+    if(PACKAGE_FIND_VERSION_PRERELEASE STRGREATER "@protobuf_VERSION_PRERELEASE@")
+      set(PACKAGE_VERSION_COMPATIBLE FALSE)
+    endif()
   endif()
 endif()
 
 # Check and save build options used to create this package
 macro(_check_and_save_build_option OPTION VALUE)
   if(DEFINED ${PACKAGE_FIND_NAME}_${OPTION} AND
-    NOT ${PACKAGE_FIND_NAME}_${OPTION} EQUAL VALUE)
+    NOT ${PACKAGE_FIND_NAME}_${OPTION} STREQUAL ${VALUE})
     set(PACKAGE_VERSION_UNSUITABLE TRUE)
   endif()
-  set(${PACKAGE_FIND_NAME}_${OPTION} ${VALUE})
+  set(${PACKAGE_FIND_NAME}_${OPTION} ${VALUE} PARENT_SCOPE)
 endmacro()
 _check_and_save_build_option(WITH_ZLIB @protobuf_WITH_ZLIB@)
 _check_and_save_build_option(MSVC_STATIC_RUNTIME @protobuf_MSVC_STATIC_RUNTIME@)