Currently, if there are multiple Pipeline steps with the same function name in a Jenkins instance (e.g. The instance has 3 plugins installed that define distinct steps whose function names are all echo), any Pipelines that use echo will always use the first implementation (based on Extension ordering of the descriptor for each step), and there is no way for the user to specify that they want to use a different implementation.

Usually, it makes sense for the developers who created the steps with the same name to just rename them so they are distinct to prevent this problem, and developers of new Pipeline steps are able to use the Step extension listing to browse all open source step implementations to ensure they are not reusing an existing step name. However, there is no way for open source developers to discover step names used by proprietary plugins, so it is possible for an open source developer to inadvertently reuse a step name that is already being used by a proprietary plugin.

To work around this issue, we should provide a way to execute a step unambiguously. For example:

echo "Hello, world!" // Normal echo step
'org.jenkinsci.plugins.workflow.steps.EchoStep'('Hello, world!') // Same as above, but refers to echo by the full class name

For now, this appears to be a very rare case, so it this basic workaround seems ok, but if it becomes more common maybe we could provide a more sophisticated way to bind step names as used in a Jenkinsfile to the desired Step implementations.