import pygit2 # using version 1.15.1 in this example
import sys
import os

def walk_repo_files(repo, branch):
    tree = repo.revparse_single(branch).tree
    trees_and_paths = [(tree, [])]
    # keep going until there is no more data
    while len(trees_and_paths) != 0:
        tree, path = trees_and_paths.pop() # take the last entry        
        for entry in tree:
            if entry.filemode == pygit2.GIT_FILEMODE_TREE:
                next_tree = repo.get(entry.id)
                next_path = list(path)
                next_path.append(entry.name)
                trees_and_paths.append((next_tree, next_path,))
            else:
                yield os.path.join(*path, entry.name)

repo_path = sys.argv[1] 
branch_name = sys.argv[2]

repo = pygit2.Repository(repo_path)

for entry in walk_repo_files(repo, branch_name):
    sys.stdout.write(entry)
    sys.stdout.write("\n")