Here is an example that shows how I track dependencies on bugs, because there is no better way to do it at the moment. Five years ago while developing a script to work with redmine I ran into this bug:
I made a hack to work around it and added a comment in the sources to explain it:
# # Hack because # http://www.redmine.org/projects/redmine/wiki/Rest_CustomFields # requires administrative permissions. It can be removed when # https://www.redmine.org/issues/18875 # is resolved. #
It would have been more convenient to have a way to reference it from the issue tracker of the project to keep it around. But that was not possible at the time: the software containing the hack is hosted on GitLab and the bug on redmine.
But even that would not have helped and this is where it gets interesting. Since I was the only one working on this software I did not bother to use the tracker and although I kept a copy of the GitLab instance around for backups, I moved the project a few weeks ago to a new GitLab instance by importing the sources only, via git. So the issue would have been lost anyways. Unless… it was stored in the DVCS itself, which is precisely what fedeproxy is planning to do.
P.S. Fun fact: the bug is still open five years later.