Is there any documentation about how Revision.Description is populated and under what condition?

Question

Is there any documentation about how Revision.Description is populated and under what condition?

I'm writing a Custom Application for Rally so that I can view changes made to Task and HierarchicalRequirement objects via a table with a rolling 7 day period.

The attributes that I'm interested in are:

HierarchicalRequirement

• PlanEstimate
• TaskEstimateTotal
• TaskActualTotal
• TaskRemainingTotal

Task

• Estimate
• ToDo
• Actuals

I'm traversing Revisions to get snapshot views of tasks and stories:

It's easy to retrieve these attributes for the current day. However, I need to traverse RevisionHistory -> Revisions and then parse the Revision.Description to apply the differences for Task and HierarchicalRequirement objects. This may provide a daily snapshot of each object.

For example: the following were appended to Revision.Description after took place:

TASK REMAINING TOTAL changed from [7.0] to [4.0]
TASK ESTIMATE TOTAL changed from [7.0] to [4.0]

The "rolling 7 day" period is just an example. My intention is to create a table with a breakdown of Team -> Story -> Task -> Estimate -> ToDo along the y-axis and Iteration -> daily-date along the x-axis.

Tim.