Fix implementation of django-filter

docs/changelog.rst

@@ -17,6 +17,10 @@ Changelog
   declaring ``PAPERLESS_DBUSER`` in your environment.  This will attempt to
   connect to your Postgres database without a password unless you also set
   ``PAPERLESS_DBPASS``.
+* A bug was found in the REST API filter system that was the result of an
+  update of django-filter some time ago.  This has now been patched `#412`_.
+  Thanks to `thepill`_ for spotting it!
+
 
 2.3.0
 =====
@@ -520,6 +524,7 @@ bulk of the work on this big change.
 .. _dubit0: https://github.com/dubit0
 .. _ahyear: https://github.com/ahyear
 .. _jonaswinkler: https://github.com/jonaswinkler
+.. _thepill: https://github.com/thepill
 
 .. _#20: https://github.com/danielquinn/paperless/issues/20
 .. _#44: https://github.com/danielquinn/paperless/issues/44
@@ -607,6 +612,7 @@ bulk of the work on this big change.
 .. _#400: https://github.com/danielquinn/paperless/pull/400
 .. _#401: https://github.com/danielquinn/paperless/pull/401
 .. _#405: https://github.com/danielquinn/paperless/pull/405
+.. _#412: https://github.com/danielquinn/paperless/issues/412
 
 .. _pipenv: https://docs.pipenv.org/
 .. _a new home on Docker Hub: https://hub.docker.com/r/danielquinn/paperless/

src/documents/filters.py

@@ -1,8 +1,14 @@
-from django_filters.rest_framework import CharFilter, FilterSet, BooleanFilter
+from django_filters.rest_framework import CharFilter, FilterSet, BooleanFilter, ModelChoiceFilter
 
 from .models import Correspondent, Document, Tag
 
 
+CHAR_KWARGS = (
+    "startswith", "endswith", "contains",
+    "istartswith", "iendswith", "icontains"
+)
+
+
 class CorrespondentFilterSet(FilterSet):
 
     class Meta:
@@ -31,34 +37,24 @@ class TagFilterSet(FilterSet):
 
 class DocumentFilterSet(FilterSet):
 
-    CHAR_KWARGS = {
-        "lookup_expr": (
-            "startswith",
-            "endswith",
-            "contains",
-            "istartswith",
-            "iendswith",
-            "icontains"
+    tags_empty = BooleanFilter(
+        label="Is tagged",
+        field_name="tags",
+        lookup_expr="isnull",
+        exclude=True
     )
-    }
-
-    correspondent__name = CharFilter(
-        field_name="correspondent__name", **CHAR_KWARGS)
-    correspondent__slug = CharFilter(
-        field_name="correspondent__slug", **CHAR_KWARGS)
-    tags__name = CharFilter(
-        field_name="tags__name", **CHAR_KWARGS)
-    tags__slug = CharFilter(
-        field_name="tags__slug", **CHAR_KWARGS)
-    tags__empty = BooleanFilter(
-        field_name="tags", lookup_expr="isnull", distinct=True)
 
     class Meta:
         model = Document
         fields = {
-            "title": [
-                "startswith", "endswith", "contains",
-                "istartswith", "iendswith", "icontains"
-            ],
-            "content": ["contains", "icontains"],
+
+            "title": CHAR_KWARGS,
+            "content": ("contains", "icontains"),
+
+            "correspondent__name": CHAR_KWARGS,
+            "correspondent__slug": CHAR_KWARGS,
+
+            "tags__name": CHAR_KWARGS,
+            "tags__slug": CHAR_KWARGS,
+
         }