Allow filtering issues by any assignee (#33343)

This is the opposite of the "No assignee" filter, it will match all
issues that have at least one assignee.

Before
![Before
change](https://github.com/user-attachments/assets/4aea194b-9add-4a84-8d6b-61bfd8d9e58e)

After
![After change with any
filter](https://github.com/user-attachments/assets/99f1205d-ba9f-4a0a-a60b-cc1a0c0823fe)

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

8 files changed, 91 insertions, 30 deletions

diff --git a/modules/indexer/issues/bleve/bleve.go b/modules/indexer/issues/bleve/bleve.go
index 9534b0b750..39d96cab98 100644
--- a/modules/indexer/issues/bleve/bleve.go
+++ b/modules/indexer/issues/bleve/bleve.go
@@ -5,11 +5,13 @@ package bleve
 
 import (
 	"context"
+	"strconv"
 
 	"code.gitea.io/gitea/modules/indexer"
 	indexer_internal "code.gitea.io/gitea/modules/indexer/internal"
 	inner_bleve "code.gitea.io/gitea/modules/indexer/internal/bleve"
 	"code.gitea.io/gitea/modules/indexer/issues/internal"
+	"code.gitea.io/gitea/modules/optional"
 	"code.gitea.io/gitea/modules/util"
 
 	"github.com/blevesearch/bleve/v2"
@@ -246,12 +248,20 @@ func (b *Indexer) Search(ctx context.Context, options *internal.SearchOptions) (
 		queries = append(queries, inner_bleve.NumericEqualityQuery(options.ProjectColumnID.Value(), "project_board_id"))
 	}
 
-	if options.PosterID.Has() {
-		queries = append(queries, inner_bleve.NumericEqualityQuery(options.PosterID.Value(), "poster_id"))
+	if options.PosterID != "" {
+		// "(none)" becomes 0, it means no poster
+		posterIDInt64, _ := strconv.ParseInt(options.PosterID, 10, 64)
+		queries = append(queries, inner_bleve.NumericEqualityQuery(posterIDInt64, "poster_id"))
 	}
 
-	if options.AssigneeID.Has() {
-		queries = append(queries, inner_bleve.NumericEqualityQuery(options.AssigneeID.Value(), "assignee_id"))
+	if options.AssigneeID != "" {
+		if options.AssigneeID == "(any)" {
+			queries = append(queries, inner_bleve.NumericRangeInclusiveQuery(optional.Some[int64](1), optional.None[int64](), "assignee_id"))
+		} else {
+			// "(none)" becomes 0, it means no assignee
+			assigneeIDInt64, _ := strconv.ParseInt(options.AssigneeID, 10, 64)
+			queries = append(queries, inner_bleve.NumericEqualityQuery(assigneeIDInt64, "assignee_id"))
+		}
 	}
 
 	if options.MentionID.Has() {
diff --git a/modules/indexer/issues/db/options.go b/modules/indexer/issues/db/options.go
index 87ce398a20..3b19d742ba 100644
--- a/modules/indexer/issues/db/options.go
+++ b/modules/indexer/issues/db/options.go
@@ -54,7 +54,7 @@ func ToDBOptions(ctx context.Context, options *internal.SearchOptions) (*issue_m
 		RepoIDs:            options.RepoIDs,
 		AllPublic:          options.AllPublic,
 		RepoCond:           nil,
-		AssigneeID:         optional.Some(convertID(options.AssigneeID)),
+		AssigneeID:         options.AssigneeID,
 		PosterID:           options.PosterID,
 		MentionedID:        convertID(options.MentionID),
 		ReviewRequestedID:  convertID(options.ReviewRequestedID),
diff --git a/modules/indexer/issues/dboptions.go b/modules/indexer/issues/dboptions.go
index 4f6ad96d22..4e2dff572a 100644
--- a/modules/indexer/issues/dboptions.go
+++ b/modules/indexer/issues/dboptions.go
@@ -45,11 +45,7 @@ func ToSearchOptions(keyword string, opts *issues_model.IssuesOptions) *SearchOp
 		searchOpt.ProjectID = optional.Some[int64](0) // Those issues with no project(projectid==0)
 	}
 
-	if opts.AssigneeID.Value() == db.NoConditionID {
-		searchOpt.AssigneeID = optional.Some[int64](0) // FIXME: this is inconsistent from other places, 0 means "no assignee"
-	} else if opts.AssigneeID.Value() != 0 {
-		searchOpt.AssigneeID = opts.AssigneeID
-	}
+	searchOpt.AssigneeID = opts.AssigneeID
 
 	// See the comment of issues_model.SearchOptions for the reason why we need to convert
 	convertID := func(id int64) optional.Option[int64] {
diff --git a/modules/indexer/issues/elasticsearch/elasticsearch.go b/modules/indexer/issues/elasticsearch/elasticsearch.go
index 464c0028f2..e3b1b17059 100644
--- a/modules/indexer/issues/elasticsearch/elasticsearch.go
+++ b/modules/indexer/issues/elasticsearch/elasticsearch.go
@@ -212,12 +212,22 @@ func (b *Indexer) Search(ctx context.Context, options *internal.SearchOptions) (
 		query.Must(elastic.NewTermQuery("project_board_id", options.ProjectColumnID.Value()))
 	}
 
-	if options.PosterID.Has() {
-		query.Must(elastic.NewTermQuery("poster_id", options.PosterID.Value()))
+	if options.PosterID != "" {
+		// "(none)" becomes 0, it means no poster
+		posterIDInt64, _ := strconv.ParseInt(options.PosterID, 10, 64)
+		query.Must(elastic.NewTermQuery("poster_id", posterIDInt64))
 	}
 
-	if options.AssigneeID.Has() {
-		query.Must(elastic.NewTermQuery("assignee_id", options.AssigneeID.Value()))
+	if options.AssigneeID != "" {
+		if options.AssigneeID == "(any)" {
+			q := elastic.NewRangeQuery("assignee_id")
+			q.Gte(1)
+			query.Must(q)
+		} else {
+			// "(none)" becomes 0, it means no assignee
+			assigneeIDInt64, _ := strconv.ParseInt(options.AssigneeID, 10, 64)
+			query.Must(elastic.NewTermQuery("assignee_id", assigneeIDInt64))
+		}
 	}
 
 	if options.MentionID.Has() {
diff --git a/modules/indexer/issues/indexer_test.go b/modules/indexer/issues/indexer_test.go
index 14dd6ba101..3e38ac49b7 100644
--- a/modules/indexer/issues/indexer_test.go
+++ b/modules/indexer/issues/indexer_test.go
@@ -44,6 +44,7 @@ func TestDBSearchIssues(t *testing.T) {
 	t.Run("search issues with order", searchIssueWithOrder)
 	t.Run("search issues in project", searchIssueInProject)
 	t.Run("search issues with paginator", searchIssueWithPaginator)
+	t.Run("search issues with any assignee", searchIssueWithAnyAssignee)
 }
 
 func searchIssueWithKeyword(t *testing.T) {
@@ -176,19 +177,19 @@ func searchIssueByID(t *testing.T) {
 	}{
 		{
 			opts: SearchOptions{
-				PosterID: optional.Some(int64(1)),
+				PosterID: "1",
 			},
 			expectedIDs: []int64{11, 6, 3, 2, 1},
 		},
 		{
 			opts: SearchOptions{
-				AssigneeID: optional.Some(int64(1)),
+				AssigneeID: "1",
 			},
 			expectedIDs: []int64{6, 1},
 		},
 		{
-			// NOTE: This tests no assignees filtering and also ToSearchOptions() to ensure it will set AssigneeID to 0 when it is passed as -1.
-			opts:        *ToSearchOptions("", &issues.IssuesOptions{AssigneeID: optional.Some(db.NoConditionID)}),
+			// NOTE: This tests no assignees filtering and also ToSearchOptions() to ensure it handles the filter correctly
+			opts:        *ToSearchOptions("", &issues.IssuesOptions{AssigneeID: "(none)"}),
 			expectedIDs: []int64{22, 21, 16, 15, 14, 13, 12, 11, 20, 5, 19, 18, 10, 7, 4, 9, 8, 3, 2},
 		},
 		{
@@ -462,3 +463,25 @@ func searchIssueWithPaginator(t *testing.T) {
 		assert.Equal(t, test.expectedTotal, total)
 	}
 }
+
+func searchIssueWithAnyAssignee(t *testing.T) {
+	tests := []struct {
+		opts          SearchOptions
+		expectedIDs   []int64
+		expectedTotal int64
+	}{
+		{
+			SearchOptions{
+				AssigneeID: "(any)",
+			},
+			[]int64{17, 6, 1},
+			3,
+		},
+	}
+	for _, test := range tests {
+		issueIDs, total, err := SearchIssues(t.Context(), &test.opts)
+		require.NoError(t, err)
+		assert.Equal(t, test.expectedIDs, issueIDs)
+		assert.Equal(t, test.expectedTotal, total)
+	}
+}
diff --git a/modules/indexer/issues/internal/model.go b/modules/indexer/issues/internal/model.go
index 976e2d696b..0d4f0f727d 100644
--- a/modules/indexer/issues/internal/model.go
+++ b/modules/indexer/issues/internal/model.go
@@ -97,9 +97,8 @@ type SearchOptions struct {
 	ProjectID       optional.Option[int64] // project the issues belong to
 	ProjectColumnID optional.Option[int64] // project column the issues belong to
 
-	PosterID optional.Option[int64] // poster of the issues
-
-	AssigneeID optional.Option[int64] // assignee of the issues, zero means no assignee
+	PosterID   string // poster of the issues, "(none)" or "(any)" or a user ID
+	AssigneeID string // assignee of the issues, "(none)" or "(any)" or a user ID
 
 	MentionID optional.Option[int64] // mentioned user of the issues
 
diff --git a/modules/indexer/issues/internal/tests/tests.go b/modules/indexer/issues/internal/tests/tests.go
index 0483853dfd..6e92c7885c 100644
--- a/modules/indexer/issues/internal/tests/tests.go
+++ b/modules/indexer/issues/internal/tests/tests.go
@@ -379,7 +379,7 @@ var cases = []*testIndexerCase{
 			Paginator: &db.ListOptions{
 				PageSize: 5,
 			},
-			PosterID: optional.Some(int64(1)),
+			PosterID: "1",
 		},
 		Expected: func(t *testing.T, data map[int64]*internal.IndexerData, result *internal.SearchResult) {
 			assert.Len(t, result.Hits, 5)
@@ -397,7 +397,7 @@ var cases = []*testIndexerCase{
 			Paginator: &db.ListOptions{
 				PageSize: 5,
 			},
-			AssigneeID: optional.Some(int64(1)),
+			AssigneeID: "1",
 		},
 		Expected: func(t *testing.T, data map[int64]*internal.IndexerData, result *internal.SearchResult) {
 			assert.Len(t, result.Hits, 5)
@@ -415,7 +415,7 @@ var cases = []*testIndexerCase{
 			Paginator: &db.ListOptions{
 				PageSize: 5,
 			},
-			AssigneeID: optional.Some(int64(0)),
+			AssigneeID: "(none)",
 		},
 		Expected: func(t *testing.T, data map[int64]*internal.IndexerData, result *internal.SearchResult) {
 			assert.Len(t, result.Hits, 5)
@@ -647,6 +647,21 @@ var cases = []*testIndexerCase{
 			}
 		},
 	},
+	{
+		Name: "SearchAnyAssignee",
+		SearchOptions: &internal.SearchOptions{
+			AssigneeID: "(any)",
+		},
+		Expected: func(t *testing.T, data map[int64]*internal.IndexerData, result *internal.SearchResult) {
+			assert.Len(t, result.Hits, 180)
+			for _, v := range result.Hits {
+				assert.GreaterOrEqual(t, data[v.ID].AssigneeID, int64(1))
+			}
+			assert.Equal(t, countIndexerData(data, func(v *internal.IndexerData) bool {
+				return v.AssigneeID >= 1
+			}), result.Total)
+		},
+	},
 }
 
 type testIndexerCase struct {
diff --git a/modules/indexer/issues/meilisearch/meilisearch.go b/modules/indexer/issues/meilisearch/meilisearch.go
index a1746f5954..759a98473f 100644
--- a/modules/indexer/issues/meilisearch/meilisearch.go
+++ b/modules/indexer/issues/meilisearch/meilisearch.go
@@ -187,12 +187,20 @@ func (b *Indexer) Search(ctx context.Context, options *internal.SearchOptions) (
 		query.And(inner_meilisearch.NewFilterEq("project_board_id", options.ProjectColumnID.Value()))
 	}
 
-	if options.PosterID.Has() {
-		query.And(inner_meilisearch.NewFilterEq("poster_id", options.PosterID.Value()))
-	}
-
-	if options.AssigneeID.Has() {
-		query.And(inner_meilisearch.NewFilterEq("assignee_id", options.AssigneeID.Value()))
+	if options.PosterID != "" {
+		// "(none)" becomes 0, it means no poster
+		posterIDInt64, _ := strconv.ParseInt(options.PosterID, 10, 64)
+		query.And(inner_meilisearch.NewFilterEq("poster_id", posterIDInt64))
+	}
+
+	if options.AssigneeID != "" {
+		if options.AssigneeID == "(any)" {
+			query.And(inner_meilisearch.NewFilterGte("assignee_id", 1))
+		} else {
+			// "(none)" becomes 0, it means no assignee
+			assigneeIDInt64, _ := strconv.ParseInt(options.AssigneeID, 10, 64)
+			query.And(inner_meilisearch.NewFilterEq("assignee_id", assigneeIDInt64))
+		}
 	}
 
 	if options.MentionID.Has() {