Use branch ref when getting last commit

- Ensures raw file importer doesn't fail when `init.defaultBranch` is
  not set to `master` on the machine where lorry is running.
- Avoids use of `--initial-branch` on repository init which is only
  supported in git versions >=2.28.0

1 files changed, 3 insertions, 3 deletions

diff --git a/lorry.raw-file-importer b/lorry.raw-file-importer
index 0a63003..bca46b5 100755
--- a/lorry.raw-file-importer
+++ b/lorry.raw-file-importer
@@ -86,13 +86,13 @@ def commit_lfs_file(raw_file, relative_path, last_commit, fast_import):
 
 def get_last_commit():
     # show the full hash of the latest commit
-    out = subprocess.run(['git', 'rev-parse', 'HEAD'], capture_output=True, text=True)
+    out = subprocess.run(['git', 'rev-parse', branch_ref], capture_output=True, text=True)
     if out.returncode != 0:
         return None
 
-    # Will be HEAD when no commits exist yet
+    # Will be same string as input when no commits exist yet
     out = out.stdout.strip()
-    return None if out == 'HEAD' else out
+    return None if out == branch_ref else out
 
 
 def main():