Fix EventsExecutor segfault when a task raises an exception (#1718)

nodes_ is a pybind11::set, which is not subscriptable. nodes_[0] compiles because object_api::operator[] accepts a py::handle and the literal 0 converts to a null handle, so pybind builds py::str(nullptr) and the process dies in strlen(). The line only runs when a task raises and exactly one node is registered, which is why normal use never reaches it.

Take the element through py::list(nodes_), as the file already does when iterating nodes_ elsewhere.

Three tests in test_executor.py were excluded from EventsExecutor because of this crash; re-enable them.

Signed-off-by: Puja catplotlib@gmail.com

rclpy

ROS Client Library for the Python language.

Documentation

Examples and tutorials for using RCLPy can be found at docs.ros.org. The latest function-level API documentation for RCLPy can be found in our API documentation or via searching for RCLPy on ROS Index.

Building documentation

Documentation can be built for rclpy using Sphinx, or accessed online.

For building documentation, you need an installation of ROS 2.

Install dependencies

sudo apt install \
  python3-sphinx \
  python3-sphinx-autodoc-typehints \
  python3-sphinx-rtd-theme

Build

Source your ROS 2 installation, for example:

. /opt/ros/rolling/setup.bash

Build code:

mkdir -p rclpy_ws/src
cd rclpy_ws/src
git clone https://github.com/ros2/rclpy.git
cd ..
colcon build --symlink-install

Source workspace and build docs:

source install/setup.bash
cd src/rclpy/rclpy/docs
make html

Contributions

Please read the ROS 2 Contribution Guide available on docs.ros.org before contributing. If you are looking for a place to start consider checking out our issues tagged help wanted and good first issue Pull request reviews from new community members are welcomed and encouraged! Please check out the pull request, build it, and run the tests, before reviewing the code. For new feature contributions, please consider filing an issue with the enhancement tag first, so we can discuss it ahead of time. Additional support and contribution resources are listed on our documentation landing page.