Fix multiple dependency descriptor generation

cmake/gz_msgs_generate.cmake

@@ -24,7 +24,6 @@ function(gz_msgs_generate_messages_impl)
     PYTHON_INTERPRETER
     PROTOC_EXEC
     PROTO_PACKAGE MSGS_GEN_SCRIPT GZ_PROTOC_PLUGIN FACTORY_GEN_SCRIPT PROTO_PATH
-    DEPENDENCY_DESCRIPTIONS
     DLLEXPORT_DECL
     OUTPUT_DIRECTORY
     # Outputs
@@ -33,7 +32,7 @@ function(gz_msgs_generate_messages_impl)
     OUTPUT_DETAIL_HEADERS
     OUTPUT_PYTHON
   )
-  set(multiValueArgs INPUT_PROTOS)
+  set(multiValueArgs INPUT_PROTOS DEPENDENCY_DESCRIPTIONS)
 
   cmake_parse_arguments(generate_messages "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
 
@@ -159,10 +158,9 @@ function(gz_msgs_generate_desc_impl)
     # Inputs
     PROTOC_EXEC
     PROTO_PATH
-    DEPENDENCY_DESCRIPTIONS
     OUTPUT_DIRECTORY
     OUTPUT_FILENAME)
-  set(multiValueArgs INPUT_PROTOS)
+  set(multiValueArgs INPUT_PROTOS DEPENDENCY_DESCRIPTIONS)
 
   cmake_parse_arguments(generate_messages "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
 
@@ -175,17 +173,22 @@ function(gz_msgs_generate_desc_impl)
   list(APPEND ARGS --descriptor_set_out=${generate_messages_OUTPUT_FILENAME})
   list(APPEND ARGS --include_imports)
 
-  foreach(dep ${generate_messages_DEPENDENCY_DESCRIPTIONS})
-    list(APPEND ARGS --descriptor_set_in="${msgs_desc_file}")
-  endforeach()
+  if(generate_messages_DEPENDENCY_DESCRIPTIONS)
+    if(WIN32)
+      list(JOIN generate_messages_DEPENDENCY_DESCRIPTIONS "$<SEMICOLON>" _desc_joined)
+    else()
+      list(JOIN generate_messages_DEPENDENCY_DESCRIPTIONS ":" _desc_joined)
+    endif()
+    list(APPEND ARGS "--descriptor_set_in=${_desc_joined}")
+  endif()
 
   list(APPEND ARGS ${generate_messages_INPUT_PROTOS})
 
   add_custom_command(
     OUTPUT ${generate_messages_OUTPUT_FILENAME}
     COMMAND ${generate_messages_PROTOC_EXEC}
     ARGS ${ARGS}
-    DEPENDS ${generate_messages_INPUT_PROTOS}
+    DEPENDS ${generate_messages_INPUT_PROTOS} ${generate_messages_DEPENDENCY_DESCRIPTIONS}
     COMMENT "Generating descriptor set"
   )
 endfunction()
@@ -225,7 +228,17 @@ function(gz_msgs_generate_messages_lib)
   set(depends_proto_paths)
   set(depends_includes)
   foreach(dep ${generate_messages_DEPENDENCIES})
-    get_target_property(msgs_desc_file ${dep} GZ_MSGS_DESC_FILE)
+    # Prefer the build-time path for same-project targets; fall back to
+    # the exported install-prefix path for imported targets.
+    get_target_property(msgs_desc_file ${dep} GZ_MSGS_DESC_FILE_BUILD)
+    if(NOT msgs_desc_file)
+      get_target_property(msgs_desc_file ${dep} GZ_MSGS_DESC_FILE)
+    endif()
+    if(NOT msgs_desc_file)
+      message(FATAL_ERROR
+        "Dependency target '${dep}' does not have a GZ_MSGS_DESC_FILE or "
+        "GZ_MSGS_DESC_FILE_BUILD property. Is it a valid gz-msgs target?")
+    endif()
     list(APPEND depends_msgs_desc ${msgs_desc_file})
   endforeach()
 
@@ -279,6 +292,7 @@ function(gz_msgs_generate_messages_lib)
         SOVERSION ${PROJECT_VERSION_MAJOR}
         VERSION ${PROJECT_VERSION}
         GZ_MSGS_DESC_FILE "\$\{_IMPORT_PREFIX\}/share/gz/protos/${generate_messages_TARGET}.gz_desc"
+        GZ_MSGS_DESC_FILE_BUILD "${CMAKE_CURRENT_BINARY_DIR}/${target_name}.gz_desc"
         )
   set_property(TARGET ${target_name} PROPERTY EXPORT_PROPERTIES "GZ_MSGS_DESC_FILE")
 

examples/generating_custom_msgs/CMakeLists.txt

@@ -34,9 +34,27 @@ gz_msgs_generate_messages(
   DEPENDENCIES gz-msgs::gz-msgs
 )
 
+# Second message library with two dependencies.
+# Uses a separate proto2/ directory so that protoc cannot resolve
+# gz/custom_msgs/foo.proto from the filesystem via -I; it must come
+# from the dependency descriptor.
+gz_msgs_generate_messages(
+  TARGET msgs2
+  PROTO_PACKAGE "gz.custom_msgs2"
+  MSGS_PATH ${CMAKE_CURRENT_SOURCE_DIR}/proto2
+  MSGS_PROTOS
+    ${CMAKE_CURRENT_SOURCE_DIR}/proto2/gz/custom_msgs2/qux.proto
+  DEPENDENCIES
+    ${PROJECT_NAME}-msgs
+    gz-msgs::gz-msgs
+)
+
 add_executable(${PROJECT_NAME} main.cc)
 
-target_link_libraries(${PROJECT_NAME} PUBLIC ${PROJECT_NAME}-msgs)
+target_link_libraries(${PROJECT_NAME} PUBLIC
+  ${PROJECT_NAME}-msgs
+  ${PROJECT_NAME}-msgs2
+)
 
 install(TARGETS ${PROJECT_NAME}
         LIBRARY DESTINATION lib

examples/generating_custom_msgs/main.cc

@@ -1,6 +1,7 @@
 #include <gz/custom_msgs/foo.pb.h>
 #include <gz/custom_msgs/bar.pb.h>
 #include <gz/custom_msgs/baz.pb.h>
+#include <gz/custom_msgs2/qux.pb.h>
 
 #include <google/protobuf/text_format.h>
 
@@ -62,4 +63,14 @@ int main()
     std::cout << "===============================" << std::endl;
     std::cout << "Populated Message: \n" << msg.DebugString() << std::endl;
   }
+
+  {
+    // Use Qux from the second message library (depends on both gz.msgs and
+    // gz.custom_msgs).
+    gz::custom_msgs2::Qux qux;
+    qux.mutable_header()->mutable_stamp()->set_sec(42);
+    qux.mutable_foo()->set_value(3.14);
+    qux.set_extra(2.718);
+    std::cout << "Qux Message: \n" << qux.DebugString() << std::endl;
+  }
 }

examples/generating_custom_msgs/proto2/gz/custom_msgs2/qux.proto

@@ -0,0 +1,12 @@
+syntax = "proto3";
+package gz.custom_msgs2;
+
+import "gz/msgs/header.proto";
+import "gz/custom_msgs/foo.proto";
+
+message Qux
+{
+  gz.msgs.Header header = 1;
+  gz.custom_msgs.Foo foo = 2;
+  double extra = 3;
+}

tools/gz_msgs_generate.py

@@ -69,8 +69,7 @@ def main(argv=sys.argv[1:]):
         cmd += [f'--proto_path={path}']
 
     if args.dependency_proto_descs:
-        for path in args.dependency_proto_descs:
-            cmd += [f'--descriptor_set_in={path}']
+        cmd += [f'--descriptor_set_in={os.pathsep.join(args.dependency_proto_descs)}']
 
     if args.generate_cpp:
         cmd += [f'--plugin=protoc-gen-gzmsgs={args.gz_generator_bin}']