fix: give priority to small usernames when query is small

Basically, when the search is "joe" we first try to search for
an exact account named "joe", and fallback to normal flow when
nothing matches.

fix #2591

umap/autocomplete.py

@@ -2,6 +2,7 @@ from agnocomplete.core import AgnocompleteModel
 from agnocomplete.register import register
 from django.conf import settings
 from django.contrib.auth import get_user_model
+from django.db.models import Q
 
 
 @register
@@ -13,3 +14,24 @@ class AutocompleteUser(AgnocompleteModel):
         data = super().item(current_item)
         data["url"] = current_item.get_url()
         return data
+
+    def get_queryset_filters(self, query):
+        if len(query) <= 3 and self._force_exact:
+            conditions = Q()
+            for field_name in self.fields:
+                if not field_name[0].isalnum():
+                    field_name = field_name[1:]
+                # Force exact match
+                conditions |= Q(**{self._construct_qs_filter(f"={field_name}"): query})
+            return conditions
+
+        return super().get_queryset_filters(query)
+
+    def build_filtered_queryset(self, query, **kwargs):
+        self._force_exact = len(query) <= 3
+        qs = super().build_filtered_queryset(query, **kwargs)
+        if len(query) <= 3 and not len(qs):
+            # Not exact match, let's fallback to normal "startswith" query
+            self._force_exact = False
+            qs = super().build_filtered_queryset(query, **kwargs)
+        return qs

umap/tests/test_views.py

@@ -510,3 +510,18 @@ def test_can_combine_search_and_filter(client, map):
     url = reverse("search")
     response = client.get(url + "?q=dur&tags=bike")
     assert "Blé dur" in response.content.decode()
+
+
+@pytest.mark.django_db
+def test_can_find_small_usernames(client):
+    UserFactory(username="Joe")
+    UserFactory(username="JoeJoe")
+    url = "/agnocomplete/AutocompleteUser/"
+    response = client.get(url + "?q=joe")
+    data = json.loads(response.content)["data"]
+    assert len(data) == 1
+    assert data[0]["label"] == "Joe"
+    response = client.get(url + "?q=joej")
+    data = json.loads(response.content)["data"]
+    assert len(data) == 1
+    assert data[0]["label"] == "JoeJoe"