Fix bug with breadcrumbs and request=None, closes #1849

datasette/app.py

@@ -633,15 +633,18 @@ class Datasette:
 
     async def _crumb_items(self, request, table=None, database=None):
         crumbs = []
+        actor = None
+        if request:
+            actor = request.actor
         # Top-level link
         if await self.permission_allowed(
-            actor=request.actor, action="view-instance", default=True
+            actor=actor, action="view-instance", default=True
         ):
             crumbs.append({"href": self.urls.instance(), "label": "home"})
         # Database link
         if database:
             if await self.permission_allowed(
-                actor=request.actor,
+                actor=actor,
                 action="view-database",
                 resource=database,
                 default=True,
@@ -656,7 +659,7 @@ class Datasette:
         if table:
             assert database, "table= requires database="
             if await self.permission_allowed(
-                actor=request.actor,
+                actor=actor,
                 action="view-table",
                 resource=(database, table),
                 default=True,

tests/test_internals_datasette.py

@@ -125,3 +125,12 @@ async def test_datasette_ensure_permissions_check_visibility(
     visible, private = await ds.check_visibility(actor, permissions=permissions)
     assert visible == should_allow
     assert private == expected_private
+
+
+@pytest.mark.asyncio
+async def test_datasette_render_template_no_request():
+    # https://github.com/simonw/datasette/issues/1849
+    ds = Datasette([], memory=True)
+    await ds.invoke_startup()
+    rendered = await ds.render_template("error.html")
+    assert "Error " in rendered