Certainly true that JIRA is neither Gratis nor Libre, nor does Atlassian accepted patches from the public. But it's Open Source in the sense that every license holder can download and build it: http://confluence.atlassian.com/display/JIRA/Building+JIRA+f...

(disclosure: I am a former Atlassian employee)

I recently started using Phabricator (http://phabricator.org/), which is open-source, and find that it's quite easy to use/set up. It's also used and well regarded by a number of startups, including Facebook, Asana and Quora.

Disclaimer: I've made minor contributions to Phabricator and will be making larger ones shortly.

git would be enough. Committers could use whatever they want to merge. Most people would choose github. But git is GPL, not Apache. Thus the problem...

nope github has been opensource for awhile dude