is it possible to retrieve all available milestones for a project via the REST API? Querying "(Project contains some_project_id)" doesn't return milestones associated with all project under a workspace.
The API query below will retrieve all the milestones for a given project. It will be necessary to change the Project OID (highlighted in yellow below) to the Project you are wanting the list of Milestones for.
https://rally1.rallydev.com/slm/webservice/v2.x/milestone?compact=true&fetch=Artifacts,Name,CreationDate,LastUpdateDate,FormattedID,TotalArtifactCount,Project,Projects,TotalProjectCount,TargetDate&query=((Projects contains "/project/611545082229") OR (Projects.ObjectID = null))&start=1&pagesize=200&order=FormattedID DESC