YAML-CPP exception when loading VLP16db.yaml

[ds-ssj]

** Environment **

• OS and Version: Ubuntu 18.04
• ROS Version: ROS2 dashing
• Built from Source or Downloaded from Official Repository:
• Version: 2.0.0-1bionic.20201125.071158

Describe the bug When run velodyne_transform_node by using VLP16db.yaml provided under the repo, an exception shows that:

[INFO] [velodyne_transform_node]: correction angles: ./VLP16db.yaml
terminate called after throwing an instance of 'std::runtime_error'
  what():  YAML Exception: yaml-cpp: error at line 0, column 0: invalid node; this may result from using a map iterator as a sequence iterator, or vice-versa

To Reproduce Steps to reproduce the behavior:

1. sudo apt install ros-dashing-velodyne
2. source ros2 the setup script
3. write a ROS2 velodyne_transform_param.yaml config file like that:

---
velodyne_transform_node:
  ros__parameters:
    min_range: 0.9
    calibration: "./VLP16db.yaml"

4. run by the command ros2 run velodyne_pointcloud velodyne_transform_node __params:=./velodyne_transform_param.yaml

Expected behavior Run it correctly

Additional context Add any other context about the problem here.

[ds-ssj]

** Environment **

• OS and Version: Ubuntu 18.04
• ROS Version: ROS2 dashing
• Built from Source or Downloaded from Official Repository:
• Version: 2.0.0-1bionic.20201125.071158

Describe the bug When run velodyne_transform_node by using VLP16db.yaml provided under the repo, an exception shows that:

[INFO] [velodyne_transform_node]: correction angles: ./VLP16db.yaml
terminate called after throwing an instance of 'std::runtime_error'
  what():  YAML Exception: yaml-cpp: error at line 0, column 0: invalid node; this may result from using a map iterator as a sequence iterator, or vice-versa

To Reproduce Steps to reproduce the behavior:

1. sudo apt install ros-dashing-velodyne
2. source ros2 the setup script
3. write a ROS2 velodyne_transform_param.yaml config file like that:

---
velodyne_transform_node:
  ros__parameters:
    min_range: 0.9
    calibration: "./VLP16db.yaml"

1. run by the command ros2 run velodyne_pointcloud velodyne_transform_node __params:=./velodyne_transform_param.yaml

Expected behavior Run it correctly

Additional context Add any other context about the problem here.

I test the yaml-cpp lib v6.0, 5.3, 5.2, 5.0, and all of them produce this bug. Thx!

[nshahrestani]

Try providing the full yaml file path and not appending a period at the beginning.