Plugin name attributes should be unique

[scpeters]

I think the //plugin/@name attribute is currently being misused by ign-gazebo, since it currently contains an ignition::gazebo::systems::SystemName and might not be unique among its sibling elements. This is a violation of the SDFormat 1.7 spec, which requires that sibling elements of any type should have unique names. It even violates the convention of earlier versions of the SDFormat spec, which required sibling elements of the same type to have unique names.

I think it would be more suitable to use a custom namespaced attribute to store the system name and give a unique name in the name attribute instead:

<plugin name='unique_name' filename='...' ignition:system='ignition::gazebo::systems::SystemName' />

[chapulina]

the //plugin/@name attribute is currently being misused by ign-gazebo

Agreed

use a custom namespaced attribute

Is this already supported by SDFormat? If so, I suggest we:

• add support for it on Citadel
• convert all our examples to use the new syntax
• deprecate the use of name as the class name on Edifice
• remove the use of name as the class name on Ign-F

[scpeters]

Is this already supported by SDFormat? If so, I suggest we:

• add support for it on Citadel
• convert all our examples to use the new syntax
• deprecate the use of name as the class name on Edifice
• remove the use of name as the class name on Ign-F

Well, we currently accept all unrecognized attributes and elements, which includes the namespaced ones; we need to re-enable warnings / errors for unrecognized fields. Some discussion here: gazebosim/sdformat#327