🐾 fix(api): cascade plain library delete; case-insensitive name conflict

DELETE /library/api/libraries/{uid}/ called bare lib.delete(), orphaning
Collections/Items/Chunks/Images and skipping Concept GC — the only delete
path not using the shared cascade. It now delegates to
delete_library_cascade like the HTML and workspace delete paths.

Name-conflict checks on both create endpoints are now case-insensitive
via find_library_by_name_ci (parameterised Cypher toLower comparison —
not neomodel iexact, which embeds the value in a regex and breaks on
names like "C++ Notes"). The Neo4j unique index is case-sensitive, so
"amazon connect" previously coexisted silently with "Amazon Connect",
confusing every name-matching client (Spelunker matches names
case-insensitively). The 409 reports the existing spelling. The plain
create also gains a UniqueProperty catch for the pre-check/save race,
mirroring the workspace path.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

mnemosyne/library/api/views.py

@@ -10,6 +10,7 @@ import os
 
 from django.core.files.base import ContentFile
 from django.core.files.storage import default_storage
+from neomodel.exceptions import UniqueProperty
 from rest_framework import status
 from rest_framework.decorators import api_view, parser_classes, permission_classes
 from rest_framework.parsers import FormParser, JSONParser, MultiPartParser
@@ -17,6 +18,7 @@ from rest_framework.permissions import IsAuthenticated
 from rest_framework.response import Response
 
 from library.content_types import get_library_type_config
+from library.services.library_delete import delete_library_cascade
 from mcp_server.drf_auth import request_token_label
 
 from .serializers import (
@@ -51,7 +53,7 @@ def library_list_create(request):
     a per-library ``item_count``. Off by default because the count is a
     Cypher aggregate; on for the Daedalus-side registry poll.
     """
-    from library.models import Library
+    from library.models import Library, find_library_by_name_ci
 
     if request.method == "GET":
         include_workspace = request.GET.get("include_workspace", "true").lower() != "false"
@@ -85,13 +87,13 @@ def library_list_create(request):
     serializer.is_valid(raise_exception=True)
     data = serializer.validated_data
 
-    # Library.name is globally unique; reject collisions with a clean 409
+    # Library names are unique. The Neo4j index is case-sensitive, but
-    # (uid + managed_by included so the caller can say who owns the name)
+    # clients (Spelunker, humans) treat names case-insensitively, so the
-    # instead of letting the unique-index save raise a 500.
+    # create-time check is case-insensitive too — otherwise "amazon connect"
-    try:
+    # silently creates a near-duplicate of "Amazon Connect". Reject with a
-        existing = Library.nodes.get(name=data["name"])
+    # clean 409 (uid + managed_by included so the caller can say who owns
-    except Library.DoesNotExist:
+    # the name) instead of letting the unique-index save raise a 500.
-        existing = None
+    existing = find_library_by_name_ci(data["name"])
     if existing is not None:
         logger.warning(
             "library_create name_conflict name=%s existing_uid=%s caller=%s",
@@ -99,7 +101,7 @@ def library_list_create(request):
         )
         return Response(
             {
-                "detail": f"A library named '{data['name']}' already exists.",
+                "detail": f"A library named '{existing.name}' already exists.",
                 "code": "name_conflict",
                 "uid": existing.uid,
                 "managed_by": existing.managed_by_display or None,
@@ -127,7 +129,22 @@ def library_list_create(request):
             data.get("llm_context_prompt") or defaults["llm_context_prompt"]
         ),
     )
-    lib.save()
+    try:
+        lib.save()
+    except UniqueProperty:
+        # Race between the pre-check and save — an exact-name twin landed
+        # in between. Same 409 shape, minus the loser's uid/manager.
+        logger.warning(
+            "library_create name_conflict (save race) name=%s caller=%s",
+            data["name"], request.user.username,
+        )
+        return Response(
+            {
+                "detail": f"A library named '{data['name']}' already exists.",
+                "code": "name_conflict",
+            },
+            status=status.HTTP_409_CONFLICT,
+        )
     return Response(LibrarySerializer(lib).data, status=status.HTTP_201_CREATED)
 
 
@@ -165,8 +182,16 @@ def library_detail(request, uid):
         lib.save()
         return Response(LibrarySerializer(lib).data)
 
-    # DELETE
+    # DELETE — use the shared cascade so child nodes (Collections/Items/
-    lib.delete()
+    # Chunks/Images) and orphan Concepts are removed too; a bare
+    # lib.delete() would leak them all.
+    result = delete_library_cascade(lib)
+    logger.info(
+        "Library deleted via API library_uid=%s name=%s items=%d "
+        "orphans_deleted=%d caller=%s",
+        result["library_uid"], result["name"], result["item_count"],
+        result["orphans_deleted"], request.user.username,
+    )
     return Response(status=status.HTTP_204_NO_CONTENT)
 
 

mnemosyne/library/api/workspaces.py

@@ -67,7 +67,7 @@ def workspace_create(request):
     workspace (200) — not an error. The library_type is frozen at first
     create; subsequent calls are not allowed to change it.
     """
-    from library.models import Library
+    from library.models import Library, find_library_by_name_ci
 
     serializer = WorkspaceCreateSerializer(data=request.data)
     serializer.is_valid(raise_exception=True)
@@ -127,6 +127,28 @@ def workspace_create(request):
             status=status.HTTP_200_OK,
         )
 
+    # New workspace: reject a name already taken by any other library,
+    # case-insensitively — the Neo4j index is case-sensitive, so without
+    # this check "amazon connect" would silently coexist with an existing
+    # "Amazon Connect" and confuse every name-matching client.
+    name_taken = find_library_by_name_ci(data["name"])
+    if name_taken is not None:
+        logger.warning(
+            "workspace_create name_conflict workspace_id=%s name=%s "
+            "existing_uid=%s",
+            data["workspace_id"], data["name"], name_taken.uid,
+        )
+        return Response(
+            {
+                "detail": (
+                    f"A library named '{name_taken.name}' already exists in "
+                    "Mnemosyne."
+                ),
+                "code": "name_conflict",
+            },
+            status=status.HTTP_409_CONFLICT,
+        )
+
     defaults = get_library_type_config(data["library_type"])
     lib = Library(
         name=data["name"],

mnemosyne/library/models.py

@@ -63,6 +63,23 @@ def infer_legacy_manager(workspace_id):
     return "Kairos" if workspace_id.startswith("kairos-mail-") else "Daedalus"
 
 
+def find_library_by_name_ci(name):
+    """Case-insensitively find a Library by name, or None.
+
+    Parameterised Cypher rather than neomodel's ``iexact``, which embeds
+    the value in a regex and so breaks on names containing regex
+    metacharacters (e.g. "C++ Notes").
+    """
+    from neomodel import db
+
+    rows, _ = db.cypher_query(
+        "MATCH (l:Library) WHERE toLower(l.name) = toLower($name) "
+        "RETURN l LIMIT 1",
+        {"name": name},
+    )
+    return Library.inflate(rows[0][0]) if rows else None
+
+
 class Library(StructuredNode):
     """
     Top-level container representing a content library.

mnemosyne/library/tests/test_library_api.py

@@ -0,0 +1,70 @@
+"""Tests for the plain library REST endpoints beyond create.
+
+Currently covers the DELETE cascade: ``DELETE /library/api/libraries/{uid}/``
+must go through ``delete_library_cascade`` (shared with the HTML and
+workspace delete paths) — a bare ``lib.delete()`` leaks Collections, Items,
+Chunks, and Images and skips orphan-Concept GC. Neo4j is stubbed via
+``sys.modules``, same style as ``test_managed_by.py``.
+"""
+
+from __future__ import annotations
+
+from types import SimpleNamespace
+from unittest.mock import MagicMock, patch
+
+from django.contrib.auth import get_user_model
+from django.test import TestCase
+from rest_framework.test import APIClient
+
+User = get_user_model()
+
+
+class LibraryApiDeleteTests(TestCase):
+    """DELETE on the plain library endpoint cascades."""
+
+    def setUp(self):
+        self.user = User.objects.create_user(username="op", password="pw")
+        self.client = APIClient()
+        self.client.force_authenticate(user=self.user)
+
+    def _fake_models_module(self, lib):
+        fake_nodes = MagicMock()
+        if lib is None:
+            class DoesNotExist(Exception):
+                pass
+
+            fake_library = SimpleNamespace(nodes=fake_nodes, DoesNotExist=DoesNotExist)
+            fake_nodes.get.side_effect = DoesNotExist()
+        else:
+            fake_library = SimpleNamespace(nodes=fake_nodes, DoesNotExist=Exception)
+            fake_nodes.get.return_value = lib
+        return SimpleNamespace(Library=fake_library)
+
+    def test_delete_uses_shared_cascade(self):
+        lib = SimpleNamespace(uid="lib-1", name="Docs")
+        cascade_result = {
+            "library_uid": "lib-1",
+            "name": "Docs",
+            "item_count": 3,
+            "item_s3_keys": [],
+            "orphans_deleted": 1,
+        }
+        with patch.dict(
+            "sys.modules", {"library.models": self._fake_models_module(lib)}
+        ), patch(
+            "library.api.views.delete_library_cascade",
+            return_value=cascade_result,
+        ) as mock_cascade:
+            response = self.client.delete("/library/api/libraries/lib-1/")
+
+        self.assertEqual(response.status_code, 204)
+        mock_cascade.assert_called_once_with(lib)
+
+    def test_delete_missing_library_returns_404(self):
+        with patch.dict(
+            "sys.modules", {"library.models": self._fake_models_module(None)}
+        ), patch("library.api.views.delete_library_cascade") as mock_cascade:
+            response = self.client.delete("/library/api/libraries/nope/")
+
+        self.assertEqual(response.status_code, 404)
+        mock_cascade.assert_not_called()

mnemosyne/library/tests/test_managed_by.py

@@ -70,8 +70,9 @@ class _FakeLibrary:
     class DoesNotExist(Exception):
         pass
 
-    existing = None          # what nodes.get(name=...) returns
+    existing = None          # what find_library_by_name_ci returns
     instances = []           # constructor kwargs, in order
+    save_raises = None       # exception instance save() should raise, if any
 
     def __init__(self, **kwargs):
         type(self).instances.append(kwargs)
@@ -81,16 +82,20 @@ class _FakeLibrary:
         self.created_at = None
 
     def save(self):
+        if type(self).save_raises is not None:
+            raise type(self).save_raises
         return self
 
-    class _Nodes:
-        @staticmethod
-        def get(**kwargs):
-            if _FakeLibrary.existing is None:
-                raise _FakeLibrary.DoesNotExist()
-            return _FakeLibrary.existing
 
-    nodes = _Nodes()
+def _fake_find_ci(name):
+    _FakeLibrary.ci_queries.append(name)
+    return _FakeLibrary.existing
+
+
+def _fake_models_module():
+    return SimpleNamespace(
+        Library=_FakeLibrary, find_library_by_name_ci=_fake_find_ci
+    )
 
 
 class LibraryCreateStampingTests(TestCase):
@@ -101,16 +106,15 @@ class LibraryCreateStampingTests(TestCase):
         self.client = APIClient()
         _FakeLibrary.existing = None
         _FakeLibrary.instances = []
+        _FakeLibrary.save_raises = None
+        _FakeLibrary.ci_queries = []
 
-    def _post(self, token=None):
+    def _post(self, token=None, name="Docs"):
         self.client.force_authenticate(user=self.user, token=token)
-        with patch.dict(
+        with patch.dict("sys.modules", {"library.models": _fake_models_module()}):
-            "sys.modules",
-            {"library.models": SimpleNamespace(Library=_FakeLibrary)},
-        ):
             return self.client.post(
                 "/library/api/libraries/",
-                {"name": "Docs", "library_type": "technical"},
+                {"name": name, "library_type": "technical"},
                 format="json",
             )
 
@@ -129,7 +133,7 @@ class LibraryCreateStampingTests(TestCase):
 
     def test_duplicate_name_returns_409_name_conflict(self):
         _FakeLibrary.existing = SimpleNamespace(
-            uid="lib-old", managed_by_display="Daedalus"
+            uid="lib-old", name="Docs", managed_by_display="Daedalus"
         )
         response = self._post(token=UserToken(name="Spelunker"))
 
@@ -141,15 +145,39 @@ class LibraryCreateStampingTests(TestCase):
         self.assertEqual(body["managed_by"], "Daedalus")
         self.assertEqual(_FakeLibrary.instances, [])
 
+    def test_duplicate_check_is_case_insensitive(self):
+        """A case-variant name 409s and reports the existing spelling."""
+        _FakeLibrary.existing = SimpleNamespace(
+            uid="lib-old", name="Amazon Connect", managed_by_display="Spelunker"
+        )
+        response = self._post(token=None, name="amazon connect")
+
+        self.assertEqual(response.status_code, 409)
+        # The lookup received the posted name (case-folding happens in
+        # Cypher), and the response names the existing spelling.
+        self.assertEqual(_FakeLibrary.ci_queries, ["amazon connect"])
+        self.assertIn("Amazon Connect", response.json()["detail"])
+        self.assertEqual(_FakeLibrary.instances, [])
+
     def test_duplicate_of_unmanaged_reports_null_manager(self):
         _FakeLibrary.existing = SimpleNamespace(
-            uid="lib-old", managed_by_display=""
+            uid="lib-old", name="Docs", managed_by_display=""
         )
         response = self._post(token=None)
 
         self.assertEqual(response.status_code, 409)
         self.assertIsNone(response.json()["managed_by"])
 
+    def test_save_race_returns_409_not_500(self):
+        """An exact-name twin landing between pre-check and save 409s."""
+        from neomodel.exceptions import UniqueProperty
+
+        _FakeLibrary.save_raises = UniqueProperty("name")
+        response = self._post(token=None)
+
+        self.assertEqual(response.status_code, 409)
+        self.assertEqual(response.json()["code"], "name_conflict")
+
 
 class WorkspaceStatusSerializerManagedByTests(TestCase):
     """The workspace status payload carries ``managed_by`` (nullable)."""