libgit2/libgit2 — pull request #2222 by ethomson (2014-03-31 02:58:25+00:00)
Title: Introduce git_merge_head_id

Callers (especially bindings) may want to know if they can fast-forward, by creating a `git_merge_head` and then inquiring about the merge status. Having a way to get the ID back out of the merge head is useful in the case where you want to perform that fast-forward. Otherwise, users would have to lug around both the merge head and the ID that it was created from.