Resolve "A Field can end up with multiple field options"

backend/src/baserow/contrib/database/api/views/gallery/views.py

@@ -137,7 +137,9 @@ class GalleryViewView(APIView):
 
         if field_options:
             context = {"fields": [o["field"] for o in model._field_objects.values()]}
-            serializer_class = view_type.get_field_options_serializer_class()
+            serializer_class = view_type.get_field_options_serializer_class(
+                create_if_missing=True
+            )
             response.data.update(**serializer_class(view, context=context).data)
 
         return response

backend/src/baserow/contrib/database/api/views/grid/views.py

@@ -186,7 +186,9 @@ class GridViewView(APIView):
 
         if field_options:
             context = {"fields": [o["field"] for o in model._field_objects.values()]}
-            serializer_class = view_type.get_field_options_serializer_class()
+            serializer_class = view_type.get_field_options_serializer_class(
+                create_if_missing=True
+            )
             response.data.update(**serializer_class(view, context=context).data)
 
         if row_metadata:

backend/src/baserow/contrib/database/api/views/serializers.py

@@ -19,8 +19,9 @@ class FieldOptionsField(serializers.Field):
         "invalid_value": "Must be valid field options.",
     }
 
-    def __init__(self, serializer_class, **kwargs):
+    def __init__(self, serializer_class, create_if_missing=True, **kwargs):
         self.serializer_class = serializer_class
+        self.create_if_missing = create_if_missing
         self._spectacular_annotation = {
             "field": serializers.DictField(
                 child=serializer_class(),
@@ -83,7 +84,9 @@ class FieldOptionsField(serializers.Field):
             fields = self.context.get("fields")
             return {
                 field_options.field_id: self.serializer_class(field_options).data
-                for field_options in value.get_field_options(True, fields)
+                for field_options in value.get_field_options(
+                    self.create_if_missing, fields
+                )
             }
         else:
             return value

backend/src/baserow/contrib/database/api/views/views.py

@@ -985,7 +985,9 @@ class ViewFieldOptionsView(APIView):
         view_type = view_type_registry.get_by_model(view)
 
         try:
-            serializer_class = view_type.get_field_options_serializer_class()
+            serializer_class = view_type.get_field_options_serializer_class(
+                create_if_missing=True
+            )
         except ValueError:
             raise ViewDoesNotSupportFieldOptions(
                 "The view type does not have a `field_options_serializer_class`"
@@ -1034,7 +1036,9 @@ class ViewFieldOptionsView(APIView):
         handler = ViewHandler()
         view = handler.get_view(view_id).specific
         view_type = view_type_registry.get_by_model(view)
-        serializer_class = view_type.get_field_options_serializer_class()
+        serializer_class = view_type.get_field_options_serializer_class(
+            create_if_missing=True
+        )
         data = validate_data(serializer_class, request.data)
 
         with view_type.map_api_exceptions():

backend/src/baserow/contrib/database/views/models.py

@@ -1,7 +1,7 @@
 import secrets
 
 from django.contrib.contenttypes.models import ContentType
-from django.db import models
+from django.db import models, transaction
 
 from baserow.core.utils import get_model_reference_field_name
 from baserow.core.models import UserFile
@@ -110,8 +110,8 @@ class View(
             them for a second time. This is only needed if `create_if_not_exists` is
             True.
         :type fields: list
-        :return: A list of field options instances related to this grid view.
-        :rtype: list or QuerySet
+        :return: A queryset containing all the field options of view.
+        :rtype: QuerySet
         """
 
         view_type = view_type_registry.get_by_model(self.specific_class)
@@ -130,20 +130,49 @@ class View(
                 "any descendants."
             )
 
-        field_options = through_model.objects.filter(**{field_name: self})
+        def get_queryset():
+            return through_model.objects.filter(**{field_name: self})
+
+        field_options = get_queryset()
 
         if create_if_not_exists:
-            field_options = list(field_options)
-            if not fields:
-                fields = Field.objects.filter(table=self.table)
+            fields_queryset = Field.objects.filter(table_id=self.table.id)
 
-            existing_field_ids = [options.field_id for options in field_options]
-            for field in fields:
-                if field.id not in existing_field_ids:
-                    field_option = through_model.objects.create(
-                        **{field_name: self, "field": field}
+            if fields is None:
+                field_count = fields_queryset.count()
+            else:
+                field_count = len(fields)
+
+            # The check there are missing field options must be as efficient as
+            # possible because this is being done a lot.
+            if len(field_options) < field_count:
+                if fields is None:
+                    fields = fields_queryset
+
+                with transaction.atomic():
+                    # Lock the view so concurrent calls to this method wont create
+                    # duplicate field options.
+                    View.objects.filter(id=self.id).select_for_update().first()
+
+                    # Invalidate the field options because they could have been
+                    # changed concurrently.
+                    field_options = get_queryset()
+
+                    # In the case when field options are missing, we can be more
+                    # in-efficient because this rarely happens. The most important part
+                    # is that the check is fast.
+                    existing_field_ids = [options.field_id for options in field_options]
+                    through_model.objects.bulk_create(
+                        [
+                            through_model(**{field_name: self, "field": field})
+                            for field in fields
+                            if field.id not in existing_field_ids
+                        ]
                     )
-                    field_options.append(field_option)
+
+                # Invalidate the field options because new ones have been created and
+                # we always want to return a queryset.
+                field_options = get_queryset()
 
         return field_options
 

backend/src/baserow/contrib/database/views/registries.py

@@ -254,12 +254,15 @@ class ViewType(
         model = view.table.get_model()
         return model._field_objects.values(), model
 
-    def get_field_options_serializer_class(self):
+    def get_field_options_serializer_class(self, create_if_missing):
         """
         Generates a serializer that has the `field_options` property as a
         `FieldOptionsField`. This serializer can be used by the API to validate or list
         the field options.
 
+         :param create_if_missing: Whether or not to create any missing field options
+            when looking them up during serialization.
+        :type create_if_missing: bool
         :raises ValueError: When the related view type does not have a field options
             serializer class.
         :return: The generated serializer.
@@ -283,7 +286,8 @@ class ViewType(
         attrs = {
             "Meta": meta,
             "field_options": FieldOptionsField(
-                serializer_class=self.field_options_serializer_class
+                serializer_class=self.field_options_serializer_class,
+                create_if_missing=create_if_missing,
             ),
         }
 
@@ -350,7 +354,9 @@ class ViewTypeRegistry(
 
     def get_field_options_serializer_map(self):
         return {
-            view_type.type: view_type.get_field_options_serializer_class()
+            view_type.type: view_type.get_field_options_serializer_class(
+                create_if_missing=False
+            )
             for view_type in self.registry.values()
         }
 

backend/src/baserow/contrib/database/views/view_types.py

@@ -102,13 +102,11 @@ class GridViewType(ViewType):
 
         grid_view = ViewHandler().get_view(view.id, view_model=GridView)
 
-        # Ensure all fields have options created before we then query directly off the
-        # options table below.
-        grid_view.get_field_options(create_if_not_exists=True)
-
         ordered_field_objects = []
         ordered_visible_fields = (
-            grid_view.get_field_options()
+            # Ensure all fields have options created before we then query directly off
+            # the options table below.
+            grid_view.get_field_options(create_if_not_exists=True)
             .filter(hidden=False)
             .order_by("-field__primary", "order", "field__id")
             .values_list("field__id", flat=True)
@@ -189,8 +187,9 @@ class GalleryViewType(ViewType):
         visible.
         """
 
-        field_options = view.get_field_options(create_if_not_exists=True)
-        field_options.sort(key=lambda x: x.field_id)
+        field_options = view.get_field_options(create_if_not_exists=True).order_by(
+            "field__id"
+        )
         ids_to_update = [f.id for f in field_options[0:3]]
 
         if ids_to_update:

backend/src/baserow/contrib/database/ws/views/signals.py

@@ -178,7 +178,9 @@ def view_sort_deleted(sender, view_sort_id, view_sort, user, **kwargs):
 def view_field_options_updated(sender, view, user, **kwargs):
     table_page_type = page_registry.get("table")
     view_type = view_type_registry.get_by_model(view.specific_class)
-    serializer_class = view_type.get_field_options_serializer_class()
+    serializer_class = view_type.get_field_options_serializer_class(
+        create_if_missing=False
+    )
     transaction.on_commit(
         lambda: table_page_type.broadcast(
             {

changelog.md

@@ -18,6 +18,7 @@
 * Allow changing the text of the submit button in the form view.
 * Fixed reordering of single select options when initially creating the field.
 * Improved performance by not rendering cells that are out of the view port.
+* Fix bug where field options in rare situations could have been duplicated.
 
 ## Released (2021-11-25)
 

premium/backend/src/baserow_premium/api/views/kanban/views.py

@@ -188,7 +188,9 @@ class KanbanViewView(APIView):
         if field_options:
             view_type = view_type_registry.get_by_model(view)
             context = {"fields": [o["field"] for o in model._field_objects.values()]}
-            serializer_class = view_type.get_field_options_serializer_class()
+            serializer_class = view_type.get_field_options_serializer_class(
+                create_if_missing=True
+            )
             response.update(**serializer_class(view, context=context).data)
 
         return Response(response)

premium/backend/src/baserow_premium/views/view_types.py

@@ -126,13 +126,10 @@ class KanbanViewType(ViewType):
         When a kanban view is created, we want to set the first three fields as visible.
         """
 
-        field_options = view.get_field_options(create_if_not_exists=True)
-        field_options.sort(key=lambda x: x.field_id)
-        ids_to_update = [
-            field_option.id
-            for index, field_option in enumerate(field_options)
-            if index < 3
-        ]
+        field_options = view.get_field_options(create_if_not_exists=True).order_by(
+            "field__id"
+        )
+        ids_to_update = [f.id for f in field_options[0:3]]
 
         if len(ids_to_update) > 0:
             KanbanViewFieldOptions.objects.filter(id__in=ids_to_update).update(