This commit hooks together all the directory rename logic by making the
necessary changes to the rename struct, it's dst_entry, and the
diff_filepair under consideration.

Signed-off-by: Elijah Newren <redacted>
---
 merge-recursive.c                   | 187 +++++++++++++++++++++++++++++++++++-
 t/t6043-merge-rename-directories.sh |  50 +++++-----
 2 files changed, 211 insertions(+), 26 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index 38dc0eefaf..7c78dc2dc1 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c

@@ -641,6 +643,27 @@ static int update_stages(struct merge_options *opt, const char *path,
        return 0;
 }

+static int update_stages_for_stage_data(struct merge_options *opt,
+                                       const char *path,
+                                       const struct stage_data *stage_data)
+{
+       struct diff_filespec o, a, b;
+
+       o.mode = stage_data->stages[1].mode;
+       oidcpy(&o.oid, &stage_data->stages[1].oid);
+
+       a.mode = stage_data->stages[2].mode;
+       oidcpy(&a.oid, &stage_data->stages[2].oid);
+
+       b.mode = stage_data->stages[3].mode;
+       oidcpy(&b.oid, &stage_data->stages[3].oid);
+
+       return update_stages(opt, path,
+                            is_null_sha1(o.oid.hash) ? NULL : &o,
+                            is_null_sha1(a.oid.hash) ? NULL : &a,
+                            is_null_sha1(b.oid.hash) ? NULL : &b);