Remap node name to fully qualified name

[jacobperron]

Feature request

Feature description

When using a fully qualified name for remapping, the node name is not remapped. For example:

ros2 run demo_nodes_cpp talker __node:=/foo

The above command does not change the node name, but I would expect the output of ros2 node list to contain /foo.

I'm not sure if this is intended to work as I expect, but it seems reasonable to me.

If this is not intended to work, then I think there should be a warning logged indicating that the remap failed. Similar to the warning when failing to remap the namespace:

$ ros2 run demo_nodes_cpp talker __ns:=foo
[WARN] [rcl]: Namespace not remapped to a fully qualified name (found: foo)

[sloretz]

Remapping to a fully qualified name requires __ns:=/ and __node:=foo.

I would have sworn there was already a ticket where it was talked about making __node:= accept a fully qualified name, but I can't find it. IIRC the trouble with __node taking a fully qualified name is what to do when a different namespace is given with __ns:=? Which namespace do topics/services use if given as relative names or ~/?

See also http://design.ros2.org/articles/static_remapping.html#supporting-change-the-node-name

[jacobperron]

I think it's okay to limit the name remap to not accept fully qualified names, but it would be nice to log a warning for invalid names.