merge: use annotated commits for recursion

Use annotated commits to act as our virtual bases, instead of regular
commits, to avoid polluting the odb with virtual base commits and
trees.  Instead, build an annotated commit with an index and pointers
to the commits that it was merged from.

1 files changed, 18 insertions, 8 deletions

diff --git a/src/annotated_commit.c b/src/annotated_commit.c
index 3998a1af1..e53b95dee 100644
--- a/src/annotated_commit.c
+++ b/src/annotated_commit.c
@@ -15,6 +15,8 @@
 #include "git2/repository.h"
 #include "git2/annotated_commit.h"
 #include "git2/revparse.h"
+#include "git2/tree.h"
+#include "git2/index.h"
 
 static int annotated_commit_init(
 	git_annotated_commit **out,
@@ -108,6 +110,8 @@ int git_annotated_commit_from_commit(
 	annotated_commit = git__calloc(1, sizeof(git_annotated_commit));
 	GITERR_CHECK_ALLOC(annotated_commit);
 
+	annotated_commit->type = GIT_ANNOTATED_COMMIT_REAL;
+
 	git_cached_obj_incref(commit);
 	annotated_commit->commit = commit;
 
@@ -179,14 +183,20 @@ void git_annotated_commit_free(git_annotated_commit *annotated_commit)
 	if (annotated_commit == NULL)
 		return;
 
-	if (annotated_commit->commit != NULL)
-		git_commit_free(annotated_commit->commit);
-
-	if (annotated_commit->ref_name != NULL)
-		git__free(annotated_commit->ref_name);
-
-	if (annotated_commit->remote_url != NULL)
-		git__free(annotated_commit->remote_url);
+	switch (annotated_commit->type) {
+		case GIT_ANNOTATED_COMMIT_REAL:
+			git_commit_free(annotated_commit->commit);
+			git_tree_free(annotated_commit->tree);
+			git__free(annotated_commit->ref_name);
+			git__free(annotated_commit->remote_url);
+			break;
+		case GIT_ANNOTATED_COMMIT_VIRTUAL:
+			git_index_free(annotated_commit->index);
+			git_array_clear(annotated_commit->parents);
+			break;
+		default:
+			abort();
+	}
 
 	git__free(annotated_commit);
 }