How to use:
1.) Place multiple tools with different IDs in your tool conf.
2.) ... ummm ... no step 2 - just use the tools.
Implementation:
The Tool Shed allows tool lineages by assigning each tool version a GUID and tracking versions in a database. This
implementation works by simply allowing the ToolBox to contain multiple tools with the same ID and orders them by the version specified by the tool author.
To track enable this a second tool lineage has been introduced that just uses tool versions instead of a database (non-toolshed installed tools are not longer placed into the Tool Shed install database). The ToolBox has been updated to allow multiple versions per tool id (defaulting to the 'latest' version for all operations which do not specify a version). Both jobs and workflow steps would track tool versions but did not use that version when fetching tools from the Toolbox - these components have been updated to try to use the tool version.
Unit tests working through most of the ToolBox and tool panel have been added, as well as functional tests exercising the tools API and to ensure workflows now at least attempt to respect tool versions (still kind of silently switches versions in some cases). Manual tests against the new tool form seem to demonstrate the tool switching and tool re-running work with only minor changes to the tools API and the job handler.
John Chilton