At work we use MKS as our tracker. We use a feature – I don’t know if it is built in or custom – called “Create Related Issue” which both clones the original and creates a relationship between the two. The cloning, though, is TOO complete, because it also clones the status of the original. So, if it is fixed in one branch, and we want to clone the issue so that we can get started on another branch, we would really want that cloned issue to start off in “New” status. If you wanted to answer the question, is it fixed in all version?, you would have to find the bug and follow the chain of links, like a linked list. There’s no one master place where you could see the parent issue and all the child versions.

Historically, what has been the problem at our company is that we think that version 3 is going to replace version 2, so we only fix the bug in version 3. Then, version 3 gets canceled and delayed and we act all surprised thinking we fixed the bug, only to realize we fixed it in a version we never released. So then, long after we did the original fix in version 3, and maybe long after the programmer who did that fix has left the company, we return to version 2. We don’t have an easy way to ask the question, “what fixes in version 3 have we *NOT* ported to version 2″.

My own BugTracker.NET doesn’t have a clone feature, so in that way it’s even worse than MKS. But, regarding the ability to view the relationships, you could add a custom field to it, “parent”, and then make all the links to the different versions go between the parent and the version. The query system is super configurable, so you could create queries that showed the parent/child relationship, that showed what fixes were done in one version but not the other.

@Fred: that’s pretty much what we do. We create new issues and link them to the original. In the end we have a graph of related issues, which “sort of” works, but has problems. For one thing, a lot of the metadata about each issue (description, synopsis, etc) is duplicated with each issue copy. The second big challenge is writing queries, because now we have to write graph traversal algorithms to produce decent reports.