RewrittenYaml does not parse integers keys #3483
Description
Bug report
- Operating System:
- Ubuntu 22.04
- ROS2 Version:
- Humble binaries
- Version or commit hash:
-Nav2 from source: 30a14090847be6f51f6cd60cbc400a0e4ac38b44 - DDS implementation:
- Cyclone
Steps to reproduce issue
RewrittenYaml method cannot properly parse yaml files with integers as key, e.g.:
node_number: 3
0:
node_name: "NODE1"
node_frequency: 50
diagnostic_message_enable: true
1:
node_name: "NODE2"
node_frequency: 20
diagnostic_message_enable: true
2:
node_name: "NODE3"
node_frequency: 20
diagnostic_message_enable: true
Expected behavior
RewrittenYaml() properly parse file and does not throw error
Actual behavior
Following error in thrown:
File "/home/antoniomarangi/ws/install/nav2_common/local/lib/python3.10/dist-packages/nav2_common/launch/rewritten_yaml.py", line 89, in perform
self.substitute_params(data, param_rewrites)
File "/home/antoniomarangi/ws/install/nav2_common/local/lib/python3.10/dist-packages/nav2_common/launch/rewritten_yaml.py", line 116, in substitute_params
yaml_paths = self.pathify(yaml)
File "/home/antoniomarangi/ws/install/nav2_common/local/lib/python3.10/dist-packages/nav2_common/launch/rewritten_yaml.py", line 156, in pathify
self.pathify(d, "", paths, joinchar=joinchar)
File "/home/antoniomarangi/ws/install/nav2_common/local/lib/python3.10/dist-packages/nav2_common/launch/rewritten_yaml.py", line 164, in pathify
self.pathify(v, pn + k, paths, joinchar=joinchar)
File "/home/antoniomarangi/ws/install/nav2_common/local/lib/python3.10/dist-packages/nav2_common/launch/rewritten_yaml.py", line 164, in pathify
self.pathify(v, pn + k, paths, joinchar=joinchar)
File "/home/antoniomarangi/ws/install/nav2_common/local/lib/python3.10/dist-packages/nav2_common/launch/rewritten_yaml.py", line 164, in pathify
self.pathify(v, pn + k, paths, joinchar=joinchar)
[Previous line repeated 3 more times]
TypeError: can only concatenate str (not "int") to str
[ERROR] [launch]: Caught exception in launch (see debug for traceback): can only concatenate str (not "int") to str
Feature description
I do not know if using integers as key is a best practice or not, but is allowed by yaml format.
Moreover, it is really practical when the number of certain parameters is known a priori but can frequently change, e.g.:
// Declare parameters
get_parameter("node_number", node_number);
for (int i = 0; i < node_number; i++)
{
std::string node_item = "nodes." + std::to_string(i);
this->declare_parameter(node_item + ".node_name", "no_name");
this->declare_parameter(node_item + ".node_frequency", 10);
this->declare_parameter(node_item + ".diagnostic_message_enable", false);
}
// Get parameters and store them
for (int i = 0; i < node_number; i++)
{
std::string node_item = "nodes." + std::to_string(i);
NodeParams np;
get_parameter<std::string>(node_item + ".node_name", np.node_name);
get_parameter<int>(node_item + ".node_frequency", np.node_frequency);
get_parameter<bool>(node_item + ".diagnostic_message_enable", np.diagnostic_message_enable);
}
Implementation considerations
A fix could consist in str casting inside RewrittenYaml.pathify()
In particulat cast to str pn and k as long with idx
def pathify(self, d, p=None, paths=None, joinchar='.'):
if p is None:
paths = {}
self.pathify(d, "", paths, joinchar=joinchar)
return paths
pn = p
if p != "":
pn += joinchar
if isinstance(d, dict):
for k in d:
v = d[k]
--------> self.pathify(v, str(pn) + str(k), paths, joinchar=joinchar) <---------------------
elif isinstance(d, list):
for idx, e in enumerate(d):
self.pathify(e, pn + str(idx), paths, joinchar=joinchar)
else:
paths[p] = d