This means that to let, e.g., testers add information to a ticket they have to do a code commit? I doubt they want to deal with that, and I don't particularly want to extend commit access to my repo to everyone who might need to interact with an issue.
Github (and plenty of other solutions) provide "edit in browser" capabilities. One could even imagine a custom web front end that enumerates the tickets, allows search, has a new/edit form that does a commit behind the scenes, etc...
Fossil SCM has all of the ticketing/bugs stored in the source control repo. Of course, in this case the repo is a SQLite database.
I still don't think I want those in the repo history, and (for a public repo) this opens up a security hole, letting arbitrary people write directly to code files. I'm not familiar at all with Fossil; perhaps its design makes this possible in a way that doesn't work so well with Git.
This means that to let, e.g., testers add information to a ticket they have to do a code commit? I doubt they want to deal with that, and I don't particularly want to extend commit access to my repo to everyone who might need to interact with an issue.