自定义话题接口编译错误

LI

vm虚拟机，Ubuntu 22 + ros humble
按教程建立工作工作空间、msg文件夹、改写了cmake.txt以及 package.xml.
编译

colcon build --packages-select demo_interface

出现如下错误：

Starting >>> demo_interface
--- stderr: demo_interface                             
Traceback (most recent call last):
  File "/opt/ros/humble/share/rosidl_generator_py/cmake/../../../lib/rosidl_generator_py/rosidl_generator_py", line 8, in <module>
    from rosidl_generator_py import generate_py
ImportError: cannot import name 'generate_py' from 'rosidl_generator_py' (/opt/ros/humble/local/lib/python3.10/dist-packages/rosidl_generator_py/__init__.py)
gmake[2]: *** [demo_interface__py/CMakeFiles/demo_interface__py.dir/build.make:180：rosidl_generator_py/demo_interface/_demo_interface_s.ep.rosidl_typesupport_fastrtps_c.c] 错误 1
gmake[1]: *** [CMakeFiles/Makefile2:590：demo_interface__py/CMakeFiles/demo_interface__py.dir/all] 错误 2
gmake[1]: *** 正在等待未完成的任务....
gmake: *** [Makefile:146：all] 错误 2
---
Failed   <<< demo_interface [1.96s, exited with code 2]

Summary: 0 packages finished [2.37s]
  1 package failed: demo_interface
  1 package had stderr output: demo_interface

小鱼

@LI 贴下你的msg,CmakeLists.txt和packages.xml，另外是否使用了conda等虚拟环境

LI

@小鱼基本是复制下来的
msg:

string content
sensor_msgs/Image image

cmake.txt

cmake_minimum_required(VERSION 3.8)
project(demo_interface)

if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
  add_compile_options(-Wall -Wextra -Wpedantic)
endif()

find_package(ament_cmake REQUIRED)

find_package(sensor_msgs REQUIRED)
find_package(rosidl_default_generators REQUIRED)

rosidl_generate_interfaces(${PROJECT_NAME}
  "msg/Novel.msg"
   DEPENDENCIES sensor_msgs
 )


if(BUILD_TESTING)
  find_package(ament_lint_auto REQUIRED)
  
  set(ament_cmake_copyright_FOUND TRUE)
  
  set(ament_cmake_cpplint_FOUND TRUE)
  ament_lint_auto_find_test_dependencies()
endif()

ament_package()

package.xml

<?xml version="1.0"?>
<?xml-model href="http://download.ros.org/schema/package_format3.xsd" schematypens="http://www.w3.org/2001/XMLSchema"?>
<package format="3">
  <name>demo_interface</name>
  <version>0.0.0</version>
  <description>TODO: Package description</description>
  <maintainer email="li-xiaoqiang@outlook.com">li</maintainer>
  <license>TODO: License declaration</license>

  <buildtool_depend>ament_cmake</buildtool_depend>

  <test_depend>ament_lint_auto</test_depend>
  <test_depend>ament_lint_common</test_depend>

  <depend>sensor_msgs</depend>
  <build_depend>rosidl_default_generators</build_depend>
  <exec_depend>rosidl_default_runtime</exec_depend>
  <member_of_group>rosidl_interface_packages</member_of_group>


  <export>
    <build_type>ament_cmake</build_type>
  </export>
</package>

安装过anaconda，但编译的时候是关闭的，不在conda环境里。

小鱼

@LI 还真没看出来错误，但是和conda估计还是有些关系，我们再检查一下这个文件，你贴一下里面的内容

/opt/ros/humble/local/lib/python3.10/dist-packages/rosidl_generator_py/__init__.py

小鱼

@LI 刚去检索了下，看到一个相同的问题，是出在conda上，你试试打开一个新的终端，运行下面的指令，如果可以成功，那就是conda确实没退出或者对PYTHONPATH产生了什么影响

$ conda deactivate
$ python3 -c 'from rosidl_generator_py import generate_py'

LI

@小鱼 /opt/ros/humble/local/lib/python3.10/dist-packages/rosidl_generator_py/init.py是这样的

# Copyright 2014-2015 Open Source Robotics Foundation, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import logging
import traceback

from .import_type_support_impl import import_type_support

__all__ = ['import_type_support']

try:
    from .generate_py_impl import generate_py
    assert generate_py
    __all__.append('generate_py')
except ImportError:
    logger = logging.getLogger('rosidl_generator_py')
    logger.debug(
        'Failed to import modules for generating Python structures:\n' + traceback.format_exc())

尝试了那两行命令，仍旧是同样的报错

小鱼

@LI 那就尝试用pip卸载重新安装写这个缺少的模块，不过这个模块代码应该就在你电脑上

LI

@小鱼最后靠着重装ros2，没改文件内容，解决了问题

小鱼

@LI 解决环境问题最好的办法就是重装了

晤易

@小鱼鱼哥，我也遇到这个问题了。这个问题到底怎么解决呀，重装了ros也没用

小鱼

@晤易你是哪个版本的ros2

晤易

@小鱼 humble 版本的

沉淀

找了半天才找到这个解决办法，系统是22.04,安装ros humble，也是报相同的错误，亲测是Conda和本机环境冲突，需要用鱼哥说的在安装中先conda deactivate

晤易

@沉淀我是 conda deactivate了还是报错，然后把之前的编译文件和日志都删除了，再重新编译就不报错了

LIME

@晤易我的情况按照你说的解决了，这个坑困扰我了一下午了。