fix(view): "Not Specified" group shows assigned issues (#10606) (#10666)

When grouping by assignee with a secondary grouping (e.g. by Status),
the "Not Specified" category passed `undefined` as the query value.
Since `undefined` is stripped during JSON serialization, the server
received no filter and returned all documents — causing assigned
issues to appear under "Not Specified".

Use `null` instead so the filter survives serialization and correctly
matches only documents where the field is unset.

Fixes #10606

Signed-off-by: Don Kendall <kendall@donkendall.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

foundations/core/packages/core/src/__tests__/query.test.ts

@@ -0,0 +1,65 @@
+//
+// Copyright © 2026 Hardcore Engineering Inc.
+//
+// Licensed under the Eclipse Public License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License. You may
+// obtain a copy of the License at https://www.eclipse.org/legal/epl-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import { findProperty } from '../query'
+import type { Doc, Ref, Class } from '../classes'
+
+function doc (id: string, fields: Record<string, any> = {}): Doc {
+  return { _id: id as Ref<Doc>, _class: 'test:class:Issue' as Ref<Class<Doc>>, ...fields } as Doc
+}
+
+describe('findProperty', () => {
+  const assigned1 = doc('i1', { assignee: 'person:1' })
+  const assigned2 = doc('i2', { assignee: 'person:2' })
+  const unassigned = doc('i3', { assignee: null })
+  const missingField = doc('i4')
+  const allDocs = [assigned1, assigned2, unassigned, missingField]
+
+  it('should match a specific value', () => {
+    const result = findProperty(allDocs, 'assignee', 'person:1')
+    expect(result).toEqual([assigned1])
+  })
+
+  it('should match null to docs with null or missing field', () => {
+    const result = findProperty(allDocs, 'assignee', null)
+    expect(result).toEqual([unassigned, missingField])
+  })
+
+  it('should match undefined to docs with null or missing field', () => {
+    const result = findProperty(allDocs, 'assignee', undefined)
+    expect(result).toEqual([unassigned, missingField])
+  })
+
+  describe('JSON round-trip (simulates server query)', () => {
+    it('null survives JSON serialization and filters correctly', () => {
+      const query = { assignee: null }
+      const roundTripped = JSON.parse(JSON.stringify(query))
+      expect(roundTripped).toHaveProperty('assignee')
+
+      const result = findProperty(allDocs, 'assignee', roundTripped.assignee)
+      expect(result).toEqual([unassigned, missingField])
+    })
+
+    it('undefined is stripped by JSON serialization, losing the filter', () => {
+      const query = { assignee: undefined }
+      const roundTripped = JSON.parse(JSON.stringify(query))
+      expect(roundTripped).not.toHaveProperty('assignee')
+
+      // Without the 'assignee' key, matchQuery iterates only the remaining keys
+      // and never calls findProperty for assignee, so all docs pass through.
+      // This is the root cause of #10606.
+    })
+  })
+})

plugins/view-resources/src/components/list/ListCategories.svelte

@@ -378,7 +378,7 @@
             : resultQuery[groupByKey]?.$in?.length !== 0
               ? undefined
               : []
-          : category
+          : category ?? null
     }
   }
 </script>