cmake: Fix pybind11_protobuf integration

Author: Mizux

cmake/check_deps.cmake

@@ -99,6 +99,10 @@ endif()
 
 # Check language Dependencies
 if(BUILD_PYTHON)
+  if(NOT TARGET pybind11::pybind11_headers)
+    message(FATAL_ERROR "Target pybind11::pybind11_headers not available.")
+  endif()
+
   if(NOT TARGET pybind11_abseil::absl_casters)
     message(FATAL_ERROR "Target pybind11_abseil::absl_casters not available.")
   endif()

patches/pybind11_protobuf.patch

@@ -1,8 +1,8 @@
 diff --git a/CMakeLists.txt b/CMakeLists.txt
-index 2139dc0..1942ad0 100644
+index 2139dc0..df3f30a 100644
 --- a/CMakeLists.txt
 +++ b/CMakeLists.txt
-@@ -27,7 +27,7 @@ include(CTest)
+@@ -27,58 +27,64 @@ include(CTest)
  # ============================================================================
  # Find Python
 
@@ -11,7 +11,106 @@ index 2139dc0..1942ad0 100644
 
  # ============================================================================
  # Build dependencies
-@@ -87,8 +87,10 @@ pybind11_add_module(
++include(FetchContent)
+ 
+-if(USE_SYSTEM_ABSEIL)
+-  # Version omitted, as absl only allows EXACT version matches
+-  set(_absl_package_args REQUIRED)
+-else()
+-  set(_absl_package_args 20230125)
+-endif()
+-if(USE_SYSTEM_PROTOBUF)
+-  set(_protobuf_package_args 4.23.3 REQUIRED)
+-else()
+-  set(_protobuf_package_args 4.23.3)
+-endif()
+-if(USE_SYSTEM_PYBIND)
+-  set(_pybind11_package_args 2.11.1 REQUIRED)
+-else()
+-  set(_pybind11_package_args 2.11.1)
++message(CHECK_START "Checking for external dependencies")
++list(APPEND CMAKE_MESSAGE_INDENT "  ")
++
++if(NOT TARGET absl::base)
++  if(USE_SYSTEM_ABSEIL)
++    # Version omitted, as absl only allows EXACT version matches
++    set(_absl_package_args REQUIRED)
++  else()
++    set(_absl_package_args 20230125)
++  endif()
++  FetchContent_Declare(
++    absl
++    GIT_REPOSITORY "https://github.com/abseil/abseil-cpp.git"
++    GIT_TAG 20230125.3
++    FIND_PACKAGE_ARGS ${_absl_package_args} NAMES absl)
++  set(ABSL_PROPAGATE_CXX_STD ON)
++  set(ABSL_ENABLE_INSTALL ON)
++  FetchContent_MakeAvailable(absl)
+ endif()
+ 
+-set(ABSL_PROPAGATE_CXX_STD ON)
+-set(ABSL_ENABLE_INSTALL ON)
++if(NOT TARGET protobuf::libprotobuf)
++  if(USE_SYSTEM_PROTOBUF)
++    set(_protobuf_package_args 4.23.3 REQUIRED)
++  else()
++    set(_protobuf_package_args 4.23.3)
++  endif()
++  FetchContent_Declare(
++    Protobuf
++    GIT_REPOSITORY "https://github.com/protocolbuffers/protobuf.git"
++    GIT_TAG v23.3
++    GIT_SUBMODULES ""
++    FIND_PACKAGE_ARGS ${_protobuf_package_args} NAMES protobuf)
++  set(protobuf_BUILD_TESTS OFF CACHE INTERNAL "")
++  FetchContent_MakeAvailable(Protobuf)
++endif()
+ 
+-include(FetchContent)
+-FetchContent_Declare(
+-  absl
+-  GIT_REPOSITORY "https://github.com/abseil/abseil-cpp.git"
+-  GIT_TAG 20230125.3
+-  FIND_PACKAGE_ARGS ${_absl_package_args} NAMES absl)
+-
+-# cmake-format: off
+-FetchContent_Declare(
+-  Protobuf
+-  GIT_REPOSITORY "https://github.com/protocolbuffers/protobuf.git"
+-  GIT_TAG v23.3
+-  GIT_SUBMODULES ""
+-  FIND_PACKAGE_ARGS ${_protobuf_package_args} NAMES protobuf)
+-set(protobuf_BUILD_TESTS OFF CACHE INTERNAL "")
+-# cmake-format: on
+-
+-FetchContent_Declare(
+-  pybind11
+-  GIT_REPOSITORY "https://github.com/pybind/pybind11.git"
+-  GIT_TAG v2.11.1
+-  FIND_PACKAGE_ARGS ${_pybind11_package_args} NAMES pybind11)
++if(NOT TARGET pybind11::pybind11_headers)
++  if(USE_SYSTEM_PYBIND)
++    set(_pybind11_package_args 2.11.1 REQUIRED)
++  else()
++    set(_pybind11_package_args 2.11.1)
++  endif()
++  FetchContent_Declare(
++    pybind11
++    GIT_REPOSITORY "https://github.com/pybind/pybind11.git"
++    GIT_TAG v2.11.1
++    FIND_PACKAGE_ARGS ${_pybind11_package_args} NAMES pybind11)
++  FetchContent_MakeAvailable(pybind11)
++endif()
+ 
+-message(CHECK_START "Checking for external dependencies")
+-list(APPEND CMAKE_MESSAGE_INDENT "  ")
+-FetchContent_MakeAvailable(absl Protobuf pybind11)
+ list(POP_BACK CMAKE_MESSAGE_INDENT)
++message(CHECK_PASS "found")
+ 
+ # ============================================================================
+ # pybind11_proto_utils pybind11 extension module
+@@ -87,8 +93,10 @@ pybind11_add_module(
    pybind11_protobuf/proto_utils.h)
 
  target_link_libraries(
@@ -24,7 +123,7 @@ index 2139dc0..1942ad0 100644
 
  target_include_directories(
    pybind11_proto_utils PRIVATE ${PROJECT_SOURCE_DIR} ${protobuf_INCLUDE_DIRS}
-@@ -116,10 +118,11 @@ target_link_libraries(
+@@ -116,10 +124,11 @@ target_link_libraries(
    absl::optional
    protobuf::libprotobuf
    pybind11::pybind11
@@ -37,7 +136,7 @@ index 2139dc0..1942ad0 100644
    PRIVATE ${PROJECT_SOURCE_DIR} ${protobuf_INCLUDE_DIRS} ${protobuf_SOURCE_DIR}
            ${pybind11_INCLUDE_DIRS})
 
-@@ -143,7 +146,7 @@ target_link_libraries(
+@@ -143,7 +152,7 @@ target_link_libraries(
    absl::optional
    protobuf::libprotobuf
    pybind11::pybind11