1 files changed, 13 insertions, 5 deletions
diff --git a/cmake/protobuf.cmake b/cmake/protobuf.cmake
index e2206a2319..cb799b5295 100644
--- a/cmake/protobuf.cmake
+++ b/cmake/protobuf.cmake
@@ -27,7 +27,7 @@ if("${gRPC_PROTOBUF_PROVIDER}" STREQUAL "module")
   if(NOT PROTOBUF_ROOT_DIR)
     set(PROTOBUF_ROOT_DIR ${CMAKE_CURRENT_SOURCE_DIR}/third_party/protobuf)
   endif()
-  set(PROTOBUF_WELLKNOWN_IMPORT_DIR ${PROTOBUF_ROOT_DIR}/src)
+
   if(EXISTS "${PROTOBUF_ROOT_DIR}/cmake/CMakeLists.txt")
     set(protobuf_MSVC_STATIC_RUNTIME OFF CACHE BOOL "Link static runtime libraries")
     add_subdirectory(${PROTOBUF_ROOT_DIR}/cmake third_party/protobuf)
@@ -41,6 +41,9 @@ if("${gRPC_PROTOBUF_PROVIDER}" STREQUAL "module")
       set(_gRPC_PROTOBUF_PROTOC protoc)
       set(_gRPC_PROTOBUF_PROTOC_EXECUTABLE $<TARGET_FILE:protoc>)
     endif()
+    set(_gRPC_PROTOBUF_INCLUDE_DIR "${PROTOBUF_ROOT_DIR}")
+    # For well-known .proto files distributed with protobuf
+    set(_gRPC_PROTOBUF_WELLKNOWN_INCLUDE_DIR "${PROTOBUF_ROOT_DIR}/src")
   else()
       message(WARNING "gRPC_PROTOBUF_PROVIDER is \"module\" but PROTOBUF_ROOT_DIR is wrong")
   endif()
@@ -50,6 +53,11 @@ if("${gRPC_PROTOBUF_PROVIDER}" STREQUAL "module")
   endif()
 elseif("${gRPC_PROTOBUF_PROVIDER}" STREQUAL "package")
   find_package(Protobuf REQUIRED ${gRPC_PROTOBUF_PACKAGE_TYPE})
+
+  # {Protobuf,PROTOBUF}_FOUND is defined based on find_package type ("MODULE" vs "CONFIG").
+  # For "MODULE", the case has also changed between cmake 3.5 and 3.6.
+  # We use the legacy uppercase version for *_LIBRARIES AND *_INCLUDE_DIRS variables
+  # as newer cmake versions provide them too for backward compatibility.
   if(Protobuf_FOUND OR PROTOBUF_FOUND)
     if(TARGET protobuf::${_gRPC_PROTOBUF_LIBRARY_NAME})
       set(_gRPC_PROTOBUF_LIBRARIES protobuf::${_gRPC_PROTOBUF_LIBRARY_NAME})
@@ -58,8 +66,11 @@ elseif("${gRPC_PROTOBUF_PROVIDER}" STREQUAL "package")
     endif()
     if(TARGET protobuf::libprotoc)
       set(_gRPC_PROTOBUF_PROTOC_LIBRARIES protobuf::libprotoc)
+      # extract the include dir from target's properties
+      get_target_property(_gRPC_PROTOBUF_WELLKNOWN_INCLUDE_DIR protobuf::libprotoc INTERFACE_INCLUDE_DIRECTORIES)
     else()
       set(_gRPC_PROTOBUF_PROTOC_LIBRARIES ${PROTOBUF_PROTOC_LIBRARIES})
+      set(_gRPC_PROTOBUF_WELLKNOWN_INCLUDE_DIR ${PROTOBUF_INCLUDE_DIRS})
     endif()
     if(TARGET protobuf::protoc)
       set(_gRPC_PROTOBUF_PROTOC protobuf::protoc)
@@ -68,10 +79,7 @@ elseif("${gRPC_PROTOBUF_PROVIDER}" STREQUAL "package")
       set(_gRPC_PROTOBUF_PROTOC ${PROTOBUF_PROTOC_EXECUTABLE})
       set(_gRPC_PROTOBUF_PROTOC_EXECUTABLE ${PROTOBUF_PROTOC_EXECUTABLE})
     endif()
+    set(_gRPC_PROTOBUF_INCLUDE_DIR ${PROTOBUF_INCLUDE_DIRS})
     set(_gRPC_FIND_PROTOBUF "if(NOT Protobuf_FOUND AND NOT PROTOBUF_FOUND)\n  find_package(Protobuf ${gRPC_PROTOBUF_PACKAGE_TYPE})\nendif()")
   endif()
-  if(PROTOBUF_FOUND)
-    include_directories(${PROTOBUF_INCLUDE_DIRS})
-  endif()
-  set(PROTOBUF_WELLKNOWN_IMPORT_DIR /usr/local/include)
 endif()