fix(indexer): fix assignee filters in issue search (#38021)

fix(indexer): fix assignee filters in issue search (#38021)

Issue search filtering still relied on the legacy single-assignee field,
so searches such as "Assigned to you" could miss issues when a keyword
query was used.

Index all issue assignee IDs and add an explicit no_assignee field so
specific, any-assignee, and no-assignee filters work consistently across
Bleve, Elasticsearch, and Meilisearch.

Fixes #36299.

modules/indexer/issues/bleve/bleve_test.go

@@ -6,7 +6,11 @@ package bleve
 import (
 	"testing"
 
+	"gitea.dev/modules/indexer/issues/internal"
 	"gitea.dev/modules/indexer/issues/internal/tests"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestBleveIndexer(t *testing.T) {
@@ -16,3 +20,67 @@ func TestBleveIndexer(t *testing.T) {
 
 	tests.TestIndexer(t, indexer)
 }
+
+func TestBleveIndexerNoAssignee(t *testing.T) {
+	dir := t.TempDir()
+	indexer := NewIndexer(dir)
+	defer indexer.Close()
+
+	_, err := indexer.Init(t.Context())
+	require.NoError(t, err)
+
+	require.NoError(t, indexer.Index(t.Context(),
+		&internal.IndexerData{ID: 1, Title: "assigned through assignee_ids", AssigneeIDs: []int64{2}},
+		&internal.IndexerData{ID: 2, Title: "unassigned", NoAssignee: true},
+		&internal.IndexerData{ID: 3, Title: "assigned through multiple assignee_ids", AssigneeIDs: []int64{3, 4}},
+	))
+
+	testCases := []struct {
+		name        string
+		opts        *internal.SearchOptions
+		expectedIDs []int64
+	}{
+		{
+			name:        "none",
+			opts:        &internal.SearchOptions{AssigneeID: "(none)"},
+			expectedIDs: []int64{2},
+		},
+		{
+			name:        "any",
+			opts:        &internal.SearchOptions{AssigneeID: "(any)"},
+			expectedIDs: []int64{1, 3},
+		},
+		{
+			name:        "specific",
+			opts:        &internal.SearchOptions{AssigneeID: "2"},
+			expectedIDs: []int64{1},
+		},
+		{
+			name:        "specific first multi-assignee",
+			opts:        &internal.SearchOptions{AssigneeID: "3"},
+			expectedIDs: []int64{3},
+		},
+		{
+			name:        "specific second multi-assignee",
+			opts:        &internal.SearchOptions{AssigneeID: "4"},
+			expectedIDs: []int64{3},
+		},
+	}
+
+	for _, testCase := range testCases {
+		t.Run(testCase.name, func(t *testing.T) {
+			result, err := indexer.Search(t.Context(), testCase.opts)
+			require.NoError(t, err)
+			assert.Equal(t, int64(len(testCase.expectedIDs)), result.Total)
+			assert.ElementsMatch(t, testCase.expectedIDs, searchResultIDs(result))
+		})
+	}
+}
+
+func searchResultIDs(result *internal.SearchResult) []int64 {
+	ids := make([]int64, 0, len(result.Hits))
+	for _, hit := range result.Hits {
+		ids = append(ids, hit.ID)
+	}
+	return ids
+}