[GITEA] enable system users search via the API

Refs: https://codeberg.org/forgejo/forgejo/issues/1403
(cherry picked from commit 87bd40411e)

Conflicts:
	routers/api/v1/user/user.go
	https://codeberg.org/forgejo/forgejo/pulls/1469
(cherry picked from commit 74f70ca873)
(cherry picked from commit 673a75bb43)
(cherry picked from commit fcd4535ac6)
(cherry picked from commit 56b229f22e)
(cherry picked from commit 45b922ae76)
(cherry picked from commit 03805f3bf4)

models/user/user_system.go

@@ -9,10 +9,12 @@ import (
 	"code.gitea.io/gitea/modules/structs"
 )
 
+const GhostUserID = -1
+
 // NewGhostUser creates and returns a fake user for someone has deleted their account.
 func NewGhostUser() *User {
 	return &User{
-		ID:        -1,
+		ID:        GhostUserID,
 		Name:      "Ghost",
 		LowerName: "ghost",
 	}

routers/api/v1/user/user.go

@@ -54,19 +54,33 @@ func Search(ctx *context.APIContext) {
 
 	listOptions := utils.GetListOptions(ctx)
 
-	users, maxResults, err := user_model.SearchUsers(ctx, &user_model.SearchUserOptions{
-		Actor:       ctx.Doer,
-		Keyword:     ctx.FormTrim("q"),
-		UID:         ctx.FormInt64("uid"),
-		Type:        user_model.UserTypeIndividual,
-		ListOptions: listOptions,
-	})
-	if err != nil {
-		ctx.JSON(http.StatusInternalServerError, map[string]any{
-			"ok":    false,
-			"error": err.Error(),
+	uid := ctx.FormInt64("uid")
+	var users []*user_model.User
+	var maxResults int64
+	var err error
+
+	switch uid {
+	case user_model.GhostUserID:
+		maxResults = 1
+		users = []*user_model.User{user_model.NewGhostUser()}
+	case user_model.ActionsUserID:
+		maxResults = 1
+		users = []*user_model.User{user_model.NewActionsUser()}
+	default:
+		users, maxResults, err = user_model.SearchUsers(ctx, &user_model.SearchUserOptions{
+			Actor:       ctx.Doer,
+			Keyword:     ctx.FormTrim("q"),
+			UID:         uid,
+			Type:        user_model.UserTypeIndividual,
+			ListOptions: listOptions,
 		})
-		return
+		if err != nil {
+			ctx.JSON(http.StatusInternalServerError, map[string]any{
+				"ok":    false,
+				"error": err.Error(),
+			})
+			return
+		}
 	}
 
 	ctx.SetLinkHeader(int(maxResults), listOptions.PageSize)

tests/integration/api_user_search_test.go

@@ -56,6 +56,28 @@ func TestAPIUserSearchNotLoggedIn(t *testing.T) {
 	}
 }
 
+func TestAPIUserSearchSystemUsers(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+	for _, systemUser := range []*user_model.User{
+		user_model.NewGhostUser(),
+		user_model.NewActionsUser(),
+	} {
+		t.Run(systemUser.Name, func(t *testing.T) {
+			req := NewRequestf(t, "GET", "/api/v1/users/search?uid=%d", systemUser.ID)
+			resp := MakeRequest(t, req, http.StatusOK)
+
+			var results SearchResults
+			DecodeJSON(t, resp, &results)
+			assert.NotEmpty(t, results.Data)
+			if assert.EqualValues(t, 1, len(results.Data)) {
+				user := results.Data[0]
+				assert.EqualValues(t, user.UserName, systemUser.Name)
+				assert.EqualValues(t, user.ID, systemUser.ID)
+			}
+		})
+	}
+}
+
 func TestAPIUserSearchAdminLoggedInUserHidden(t *testing.T) {
 	defer tests.PrepareTestEnv(t)()
 	adminUsername := "user1"