Merge pull request #1088 from gitbutlerapp/add-merge-base-octopus

Added merge_base_octopus

libgit2-sys/lib.rs

@@ -3506,6 +3506,13 @@ extern "C" {
  input_array: *const git_oid,
  ) -> c_int;
 
+ pub fn git_merge_base_octopus(
+ out: *mut git_oid,
+ repo: *mut git_repository,
+ length: size_t,
+ input_array: *const git_oid,
+ ) -> c_int;
+
  pub fn git_merge_bases(
  out: *mut git_oidarray,
  repo: *mut git_repository,

src/repo.rs

@@ -2467,6 +2467,38 @@ impl Repository {
  }
 
  /// Find a merge base given a list of commits
+ ///
+ /// This behaves similar to [`git merge-base`](https://git-scm.com/docs/git-merge-base#_discussion).
+ /// Given three commits `a`, `b`, and `c`, `merge_base_many(&[a, b, c])`
+ /// will compute a hypothetical commit `m`, which is a merge between `b`
+ /// and `c`.
+ ///
+ /// For example, with the following topology:
+ /// ```text
+ /// o---o---o---o---C
+ /// /
+ /// / o---o---o---B
+ /// / /
+ /// ---2---1---o---o---o---A
+ /// ```
+ ///
+ /// the result of `merge_base_many(&[a, b, c])` is 1. This is because the
+ /// equivalent topology with a merge commit `m` between `b` and `c` would
+ /// is:
+ /// ```text
+ /// o---o---o---o---o
+ /// / \
+ /// / o---o---o---o---M
+ /// / /
+ /// ---2---1---o---o---o---A
+ /// ```
+ ///
+ /// and the result of `merge_base_many(&[a, m])` is 1.
+ ///
+ /// ---
+ ///
+ /// If you're looking to recieve the common merge base between all the
+ /// given commits, use [`Self::merge_base_octopus`].
  pub fn merge_base_many(&self, oids: &[Oid]) -> Result<Oid, Error> {
  let mut raw = raw::git_oid {
  id: [0; raw::GIT_OID_RAWSZ],
@@ -2483,6 +2515,23 @@ impl Repository {
  }
  }
 
+ /// Find a common merge base between all given a list of commits
+ pub fn merge_base_octopus(&self, oids: &[Oid]) -> Result<Oid, Error> {
+ let mut raw = raw::git_oid {
+ id: [0; raw::GIT_OID_RAWSZ],
+ };
+
+ unsafe {
+ try_call!(raw::git_merge_base_octopus(
+ &mut raw,
+ self.raw,
+ oids.len() as size_t,
+ oids.as_ptr() as *const raw::git_oid
+ ));
+ Ok(Binding::from_raw(&raw as *const _))
+ }
+ }
+
  /// Find all merge bases between two commits
  pub fn merge_bases(&self, one: Oid, two: Oid) -> Result<OidArray, Error> {
  let mut arr = raw::git_oidarray {
@@ -3825,6 +3874,10 @@ mod tests {
  // the merge base of (oid2,oid3,oid4) should be oid1
  let merge_base = repo.merge_base_many(&[oid2, oid3, oid4]).unwrap();
  assert_eq!(merge_base, oid1);
+
+ // the octopus merge base of (oid2,oid3,oid4) should be oid1
+ let merge_base = repo.merge_base_octopus(&[oid2, oid3, oid4]).unwrap();
+ assert_eq!(merge_base, oid1);
  }
 
  /// create an octopus: