diff --git a/tools/dir2graph b/tools/dir2graph
index 0530a93..054ac61 100755
--- a/tools/dir2graph
+++ b/tools/dir2graph
@@ -1,102 +1,103 @@
 #!/usr/bin/env python3
 
 # Copyright (C) 2021  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 import sys
 from typing import Iterator, Tuple, Union
 
 import click
 
 from swh.model.from_disk import Content, Directory
 from swh.model.identifiers import CoreSWHID, ObjectType
 
 
 def swhid_of_node(obj: Union[Content, Directory]):
     return CoreSWHID(
         object_type=ObjectType[obj.object_type.upper()], object_id=obj.hash,
     )
 
 
 def walk_model(root: Directory,) -> Iterator[Tuple[CoreSWHID, Iterator[CoreSWHID]]]:
     """recursively visit a model.from_disk object
 
     Yield pairs (SWHID, neighbors) where SWHID is the identifier of a node and neighbors
     an iterator over SWHID of nodes directly reachable from it. So you can obtain all
     graph nodes by only looking at the first element of the pair, and edges by joining
     the first element with each of the neighbors.
 
     Note that no deduplication is applied, so both nodes and edges can be yielded
     multiple times if they do in fact appear multiple times in the graph.
 
     """
 
-    def walk_neighbors(node, to_visit):
+    def walk_neighbors(node):
         for child in node.values():
-            to_visit.insert(0, child)
             yield swhid_of_node(child)
 
     to_visit = [root]
     while to_visit:
         node = to_visit.pop()
         swhid = swhid_of_node(node)
-        yield (swhid, walk_neighbors(node, to_visit))
+        yield (swhid, walk_neighbors(node))
+        for child in node.values():
+            to_visit.insert(0, child)
 
 
 @click.command()
 @click.argument(
     "directory",
     required=True,
     type=click.Path(exists=True, file_okay=False, dir_okay=True),
 )
 @click.option(
     "-n",
     "--nodes-output",
     type=click.Path(file_okay=True, dir_okay=False, writable=True),
     help="output file where to store nodes as SWHIDs"
     " (if not given, node SWHIDs will not be output)."
     ' Use "-" for stdout.'
     " Default: output node SWHIDs to stdout.",
 )
 @click.option(
     "-e",
     "--edges-output",
     type=click.Path(file_okay=True, dir_okay=False, writable=True),
     help="output file where to store edges as SWHID pairs"
     " (if not given, edge SWHIDs will not be output)"
     ' Use "-" for stdout.'
     " Default: do not output edge SWHIDs.",
 )
 def main(directory, nodes_output, edges_output):
     """Recursively identifies the content of a directory.
 
     Outputs SWHID identifiers as both nodes (one SWHID per object) and edges (pairs of
     SWHIDs (parent, child) corresponding to the filesystem hierarchy).
 
     """
     nodes_file = sys.stdout
     edges_file = None
     if nodes_output:
         if nodes_output == "-":
             nodes_file = sys.stdout
         else:
             nodes_file = open(nodes_output, "w")
     if edges_output:
         if edges_output == "-":
             edges_file = sys.stdout
         else:
             edges_file = open(edges_output, "w")
 
     root = Directory.from_disk(path=directory.encode())
     for swhid, neighbors in walk_model(root):
         if nodes_file:
             nodes_file.write(f"{swhid}\n")
         if edges_file:
             for child_swhid in neighbors:
                 edges_file.write(f"{swhid} {child_swhid}\n")
 
 
 if __name__ == "__main__":
     main()