Generate Cargo.toml of message crate with an EmPy template, not CMake (#138)

* Generate Cargo.toml of message crate with an EmPy template, not CMake

* Add comment

Author: nnmm

rosidl_generator_rs/cmake/rosidl_generator_rs_generate_interfaces.cmake

@@ -67,6 +67,7 @@ endforeach()
 
 list(APPEND _generated_common_rs_files
   "${_output_path}/rust/src/lib.rs"
+  "${_output_path}/rust/Cargo.toml"
 )
 
 if(${_has_msg})
@@ -132,14 +133,6 @@ file(MAKE_DIRECTORY "${_output_path}")
 
 set(_target_suffix "__rs")
 
-set(CRATES_DEPENDENCIES "rosidl_runtime_rs = \"*\"")
-set(SERDE_FEATURES "[\"dep:serde\", \"rosidl_runtime_rs/serde\"")
-foreach(_pkg_name ${rosidl_generate_interfaces_DEPENDENCY_PACKAGE_NAMES})
-  find_package(${_pkg_name} REQUIRED)
-  set(CRATES_DEPENDENCIES "${CRATES_DEPENDENCIES}\n${_pkg_name} = \"*\"")
-  set(SERDE_FEATURES "${SERDE_FEATURES}, \"${_pkg_name}/serde\"")
-endforeach()
-  set(SERDE_FEATURES "${SERDE_FEATURES}]")
 ament_index_register_resource("rust_packages")
 
 
@@ -173,15 +166,6 @@ foreach(_typesupport_impl ${_typesupport_impls})
   endif()
 endforeach()
 
-configure_file("${rosidl_generator_rs_TEMPLATE_DIR}/Cargo.toml.in"
-  "share/${PROJECT_NAME}/rust/Cargo.toml"
-  @ONLY)
-
-install(
-  FILES "${CMAKE_CURRENT_BINARY_DIR}/share/${PROJECT_NAME}/rust/Cargo.toml"
-  DESTINATION share/${PROJECT_NAME}/rust/
-)
-
 if(BUILD_TESTING AND rosidl_generate_interfaces_ADD_LINTER_TESTS)
   if(
     NOT _generated_msg_rs_files STREQUAL "" OR

rosidl_generator_rs/resource/Cargo.toml.em

@@ -0,0 +1,22 @@
+[package]
+name = "@(package_name)"
+@# The version should ideally be taken from package.xml, see
+@# https://github.com/ros2-rust/ros2_rust/issues/116
+version = "0.2.0"
+edition = "2021"
+
+[dependencies]
+libc = "0.2"
+rosidl_runtime_rs = "*"
+serde = { version = "1", optional = true, features = ["derive"] }
+@[for dep in dependency_packages]@
+@(dep) = "*"
+@[end for]@
+
+[features]
+@{
+serde_features = ["dep:serde", "rosidl_runtime_rs/serde"]
+for dep in dependency_packages:
+	serde_features.append("{}/serde".format(dep))
+}@
+serde = @(serde_features)

rosidl_generator_rs/resource/Cargo.toml.in

@@ -59,7 +59,16 @@ def generate_rs(generator_arguments_file, typesupport_impls):
     # expand init modules for each directory
     modules = {}
     idl_content = IdlContent()
-    (Path(args['output_dir']) / 'rust/src/bindings').mkdir(parents=True, exist_ok=True)
+    dependency_packages = set()
+
+    (Path(args['output_dir']) / 'rust/src').mkdir(parents=True, exist_ok=True)
+
+    for dep_tuple in args.get('ros_interface_dependencies', []):
+        dep_parts = dep_tuple.rsplit(':', 1)
+        assert len(dep_parts) == 2
+        if dep_parts[0] != package_name:
+            dependency_packages.add(dep_parts[0])
+
     for idl_tuple in args.get('idl_tuples', []):
         idl_parts = idl_tuple.rsplit(':', 1)
         assert len(idl_parts) == 2
@@ -145,6 +154,16 @@ def generate_rs(generator_arguments_file, typesupport_impls):
         os.path.join(args['output_dir'], 'rust/src/lib.rs'),
         minimum_timestamp=latest_target_timestamp)
 
+    cargo_toml_data = {
+        'dependency_packages': dependency_packages,
+        'package_name': args['package_name'],
+    }
+    expand_template(
+        os.path.join(template_dir, 'Cargo.toml.em'),
+        cargo_toml_data,
+        os.path.join(args['output_dir'], 'rust/Cargo.toml'),
+        minimum_timestamp=latest_target_timestamp)
+
     return 0
 
 def get_rs_name(name):