fixup! ✨(backend) add "tree" action on document API endpoint

src/backend/core/api/utils.py

@@ -11,6 +11,35 @@ import botocore
 from rest_framework.throttling import BaseThrottle
 
 
+def nest_tree(flat_list, steplen):
+    """
+    Convert a flat list of serialized documents into a nested tree making advantage
+    of the`path` field and its step length.
+    """
+    node_dict = {}
+    roots = []
+
+    # Sort the flat list by path to ensure parent nodes are processed first
+    flat_list.sort(key=lambda x: x["path"])
+
+    for node in flat_list:
+        node["children"] = []  # Initialize children list
+        node_dict[node["path"]] = node
+
+        # Determine parent path
+        parent_path = node["path"][:-steplen]
+
+        if parent_path in node_dict:
+            node_dict[parent_path]["children"].append(node)
+        else:
+            roots.append(node)  # Collect root nodes
+
+    if len(roots) > 1:
+        raise ValueError("More than one root element detected.")
+
+    return roots[0] if roots else None
+
+
 def filter_root_paths(paths, skip_sorting=False):
     """
     Filters root paths from a list of paths representing a tree structure.

src/backend/core/api/viewsets.py

@@ -773,22 +773,18 @@ class DocumentViewSet(
         methods=["get"],
         ordering=["path"],
     )
-    def tree(self, request, *args, **kwargs):
+    def tree(self, request, pk, *args, **kwargs):
         """
         List ancestors tree above the document.
         What we need to display is the tree structure opened for the current document.
         """
-        lookup_url_kwarg = self.lookup_url_kwarg or self.lookup_field
-        filter_kwargs = {self.lookup_field: self.kwargs[lookup_url_kwarg]}
-        current_document = (
-            self.queryset.filter(**filter_kwargs).only("depth", "path").first()
-        )
-
-        if current_document is None:
-            raise Http404
+        try:
+            current_document = self.queryset.only("depth", "path").get(pk=pk)
+        except models.Document.DoesNotExist as excpt:
+            raise drf.exceptions.NotFound from excpt
 
         ancestors = (
-            (current_document.get_ancestors() | self.queryset.filter(**filter_kwargs))
+            (current_document.get_ancestors() | self.queryset.filter(pk=pk))
             .filter(ancestors_deleted_at__isnull=True)
             .order_by("path")
         )
@@ -830,8 +826,9 @@ class DocumentViewSet(
                 "ancestors_links_definitions": ancestors_links_definitions,
             },
         )
-
-        return drf.response.Response(serializer.data)
+        return drf.response.Response(
+            utils.nest_tree(serializer.data, self.queryset.model.steplen)
+        )
 
     @drf.decorators.action(detail=True, methods=["get"], url_path="versions")
     def versions_list(self, request, *args, **kwargs):

src/backend/core/models.py

@@ -29,7 +29,7 @@ from django.utils.translation import gettext_lazy as _
 from botocore.exceptions import ClientError
 from rest_framework.exceptions import ValidationError
 from timezone_field import TimeZoneField
-from treebeard.mp_tree import MP_Node
+from treebeard.mp_tree import MP_Node, MP_NodeManager, MP_NodeQuerySet
 
 logger = getLogger(__name__)
 
@@ -367,7 +367,7 @@ class BaseAccess(BaseModel):
         }
 
 
-class DocumentQuerySet(models.QuerySet):
+class DocumentQuerySet(MP_NodeQuerySet):
     """
     Custom queryset for the Document model, providing additional methods
     to filter documents based on user permissions.
@@ -387,10 +387,10 @@ class DocumentQuerySet(models.QuerySet):
                 | ~models.Q(link_reach=LinkReachChoices.RESTRICTED)
             )
 
-        return self.filter(models.Q(link_reach=LinkReachChoices.PUBLIC))
+        return self.filter(link_reach=LinkReachChoices.PUBLIC)
 
 
-class DocumentManager(models.Manager):
+class DocumentManager(MP_NodeManager):
     """
     Custom manager for the Document model, enabling the use of the custom
     queryset methods directly from the model manager.
@@ -619,7 +619,11 @@ class Document(MP_Node, BaseModel):
     def invalidate_nb_accesses_cache(self):
         """
         Invalidate the cache for number of accesses, including on affected descendants.
+        Args:
+            path: can optionally be passed as argument (useful when invalidating cache for a
+                document we just deleted)
         """
+
         for document in Document.objects.filter(path__startswith=self.path).only("id"):
             cache_key = document.get_nb_accesses_cache_key()
             cache.delete(cache_key)

src/backend/core/tests/test_api_utils_nest_tree.py

@@ -0,0 +1,107 @@
+"""Unit tests for the nest_tree utility function."""
+
+import pytest
+
+from core.api.utils import nest_tree
+
+
+def test_api_utils_nest_tree_empty_list():
+    """Test that an empty list returns an empty nested structure."""
+    # pylint: disable=use-implicit-booleaness-not-comparison
+    assert nest_tree([], 4) is None
+
+
+def test_api_utils_nest_tree_single_document():
+    """Test that a single document is returned as the only root element."""
+    documents = [{"id": "1", "path": "0001"}]
+    expected = {"id": "1", "path": "0001", "children": []}
+    assert nest_tree(documents, 4) == expected
+
+
+def test_api_utils_nest_tree_multiple_root_documents():
+    """Test that multiple root-level documents are correctly added to the root."""
+    documents = [
+        {"id": "1", "path": "0001"},
+        {"id": "2", "path": "0002"},
+    ]
+    with pytest.raises(
+        ValueError,
+        match="More than one root element detected.",
+    ):
+        nest_tree(documents, 4)
+
+
+def test_api_utils_nest_tree_nested_structure():
+    """Test that documents are correctly nested based on path levels."""
+    documents = [
+        {"id": "1", "path": "0001"},
+        {"id": "2", "path": "00010001"},
+        {"id": "3", "path": "000100010001"},
+        {"id": "4", "path": "00010002"},
+    ]
+    expected = {
+        "id": "1",
+        "path": "0001",
+        "children": [
+            {
+                "id": "2",
+                "path": "00010001",
+                "children": [{"id": "3", "path": "000100010001", "children": []}],
+            },
+            {"id": "4", "path": "00010002", "children": []},
+        ],
+    }
+    assert nest_tree(documents, 4) == expected
+
+
+def test_api_utils_nest_tree_siblings_at_same_path():
+    """
+    Test that sibling documents with the same path are correctly grouped under the same parent.
+    """
+    documents = [
+        {"id": "1", "path": "0001"},
+        {"id": "2", "path": "00010001"},
+        {"id": "3", "path": "00010002"},
+    ]
+    expected = {
+        "id": "1",
+        "path": "0001",
+        "children": [
+            {"id": "2", "path": "00010001", "children": []},
+            {"id": "3", "path": "00010002", "children": []},
+        ],
+    }
+    assert nest_tree(documents, 4) == expected
+
+
+def test_api_utils_nest_tree_decreasing_path_resets_parent():
+    """Test that a document at a lower path resets the parent assignment correctly."""
+    documents = [
+        {"id": "1", "path": "0001"},
+        {"id": "6", "path": "00010001"},
+        {"id": "2", "path": "00010002"},  # unordered
+        {"id": "5", "path": "000100010001"},
+        {"id": "3", "path": "000100010002"},
+        {"id": "4", "path": "00010003"},
+    ]
+    expected = {
+        "id": "1",
+        "path": "0001",
+        "children": [
+            {
+                "id": "6",
+                "path": "00010001",
+                "children": [
+                    {"id": "5", "path": "000100010001", "children": []},
+                    {"id": "3", "path": "000100010002", "children": []},
+                ],
+            },
+            {
+                "id": "2",
+                "path": "00010002",
+                "children": [],
+            },
+            {"id": "4", "path": "00010003", "children": []},
+        ],
+    }
+    assert nest_tree(documents, 4) == expected