refactor: complete removal of go-linq/x/exp, modernize Go syntax

docs/superpowers/specs/2026-03-10-caskin-modernization.md

@@ -30,15 +30,15 @@ caskin 是一个 Go 的多域 RBAC 权限管理库，基于 casbin 开发。最
 ### 任务清单
 
 - [x] 升级 Go 到最新版（1.24）
-- [ ] 依赖升级（只升无破坏性变更的小版本/patch）
-- [ ] 跑通所有现有测试，修复失败的
-- [ ] 使用新 Go 语法重构：
-  - `interface{}` → `any`
-  - `range` over integers（Go 1.22）
-  - `slices` / `maps` 标准库替换手写循环
-  - `min()` / `max()` 内置函数
-  - 适当引入泛型简化重复代码
-- [ ] 完善 README：补充真实可运行的 Quick Start 示例
+- [x] 依赖升级（只升无破坏性变更的小版本/patch）
+- [x] 完善 README：补充真实可运行的 Quick Start 示例（PR #26，已合并）
+- [x] 使用新 Go 语法重构（PR #27）：
+  - 完全移除 `go-linq` 和 `golang.org/x/exp`，替换为 stdlib
+  - `sort.Slice` → `slices.SortFunc`
+  - `constraints.Ordered` → `cmp.Ordered`
+  - BFS 循环加注释增强可读性
+  - `distinct()` 泛型函数复用
+- [ ] 跑通所有现有测试，修复失败的（✅ 当前测试全部通过）
 - [ ] 补充 godoc 注释（核心 API）
 
 **卡点：完成后汇报，等用户确认进入 Phase 2**

go.mod

@@ -4,13 +4,11 @@ go 1.24
 
 require (
 	github.com/BurntSushi/toml v1.6.0
-	github.com/ahmetb/go-linq/v3 v3.2.0
 	github.com/casbin/casbin/v2 v2.69.0
 	github.com/casbin/gorm-adapter/v3 v3.17.0
 	github.com/casbin/redis-watcher/v2 v2.5.0
 	github.com/redis/go-redis/v9 v9.0.5
 	github.com/stretchr/testify v1.11.1
-	golang.org/x/exp v0.0.0-20241108190413-2d47ceb2692f
 	gorm.io/driver/mysql v1.5.0
 	gorm.io/driver/postgres v1.5.0
 	gorm.io/driver/sqlite v1.5.0

go.sum

@@ -6,8 +6,6 @@ github.com/BurntSushi/toml v1.6.0 h1:dRaEfpa2VI55EwlIW72hMRHdWouJeRF7TPYhI+AUQjk
 github.com/BurntSushi/toml v1.6.0/go.mod h1:ukJfTF/6rtPPRCnwkur4qwRxa8vTRFBF0uk2lLoLwho=
 github.com/Knetic/govaluate v3.0.1-0.20171022003610-9aa49832a739+incompatible h1:1G1pk05UrOh0NlF1oeaaix1x8XzrfjIDK47TY0Zehcw=
 github.com/Knetic/govaluate v3.0.1-0.20171022003610-9aa49832a739+incompatible/go.mod h1:r7JcOSlj0wfOMncg0iLm8Leh48TZaKVeNIfJntJ2wa0=
-github.com/ahmetb/go-linq/v3 v3.2.0 h1:BEuMfp+b59io8g5wYzNoFe9pWPalRklhlhbiU3hYZDE=
-github.com/ahmetb/go-linq/v3 v3.2.0/go.mod h1:haQ3JfOeWK8HpVxMtHHEMPVgBKiYyQ+f1/kLZh/cj9U=
 github.com/bsm/ginkgo/v2 v2.7.0 h1:ItPMPH90RbmZJt5GtkcNvIRuGEdwlBItdNVoyzaNQao=
 github.com/bsm/ginkgo/v2 v2.7.0/go.mod h1:AiKlXPm7ItEHNc/2+OkrNG4E0ITzojb9/xWzvQ9XZ9w=
 github.com/bsm/gomega v1.26.0 h1:LhQm+AFcgV2M0WyKroMASzAzCAJVpAxQXv4SaI9a69Y=
@@ -112,8 +110,6 @@ golang.org/x/crypto v0.0.0-20220511200225-c6db032c6c88/go.mod h1:IxCIyHEi3zRg3s0
 golang.org/x/crypto v0.0.0-20221005025214-4161e89ecf1b/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
 golang.org/x/crypto v0.6.0 h1:qfktjS5LUO+fFKeJXZ+ikTRijMmljikvG68fpMMruSc=
 golang.org/x/crypto v0.6.0/go.mod h1:OFC/31mSvZgRz0V1QTNCzfAI1aIRzbiufJtkMIlEp58=
-golang.org/x/exp v0.0.0-20241108190413-2d47ceb2692f h1:XdNn9LlyWAhLVp6P/i8QYBW+hlyhrhei9uErw2B5GJo=
-golang.org/x/exp v0.0.0-20241108190413-2d47ceb2692f/go.mod h1:D5SMRVC3C2/4+F/DB1wZsLRnSNimn2Sp/NPsCrsv8ak=
 golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
 golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=

inheritance.go

@@ -4,7 +4,6 @@ import (
 	"cmp"
 	"encoding/json"
 	"slices"
-	"sort"
 )
 
 // InheritanceEdge x is node, y is adjacency
@@ -26,14 +25,14 @@ func (i *InheritanceEdge[T]) Decode(in string) error {
 type EdgeSorter[T cmp.Ordered] map[T]int
 
 func (e EdgeSorter[T]) RootFirstSort(edges []*InheritanceEdge[T]) {
-	sort.Slice(edges, func(i, j int) bool {
-		return e[edges[i].U] < e[edges[j].U]
+	slices.SortFunc(edges, func(a, b *InheritanceEdge[T]) int {
+		return cmp.Compare(e[a.U], e[b.U])
 	})
 }
 
 func (e EdgeSorter[T]) LeafFirstSort(edges []*InheritanceEdge[T]) {
-	sort.Slice(edges, func(i, j int) bool {
-		return e[edges[i].V] > e[edges[j].V]
+	slices.SortFunc(edges, func(a, b *InheritanceEdge[T]) int {
+		return cmp.Compare(e[b.V], e[a.V])
 	})
 }
 
@@ -79,6 +78,7 @@ func (g InheritanceGraph[T]) TopSort() []T {
 			queue = append(queue, k)
 		}
 	}
+	// BFS topological sort: queue grows as in-degrees reach zero
 	for i := 0; i < len(queue); i++ {
 		node := queue[i]
 		for _, v := range g[node] {

object_directory.go

@@ -22,11 +22,9 @@ func (o *objectDirectory) Search(prefix uint64, searchType DirectorySearchType)
 
 	switch searchType {
 	case DirectorySearchAll:
+		// BFS: process queue while it grows with children
 		for i := 0; i < len(out); i++ {
-			node := out[i]
-			for _, v := range o.Tree[node.GetID()] {
-				out = append(out, v)
-			}
+			out = append(out, o.Tree[out[i].GetID()]...)
 		}
 	default:
 	}

server.go

@@ -1,10 +1,10 @@
 package caskin
 
 import (
-	"github.com/ahmetb/go-linq/v3"
+	"cmp"
+
 	"github.com/casbin/casbin/v2"
 	"github.com/casbin/gorm-adapter/v3"
-	"golang.org/x/exp/constraints"
 )
 
 type server struct {
@@ -83,17 +83,33 @@ func Check[T any](e IEnforcer, u User, d Domain, one T, action Action) bool {
 	return false
 }
 
-// Diff do diff source, target list to get add, remove list
-func Diff[T constraints.Ordered](source, target []T) (add, remove []T) {
-	linq.From(source).Except(linq.From(target)).ToSlice(&remove)
-	linq.From(target).Except(linq.From(source)).ToSlice(&add)
+// Diff returns the elements to add and remove to transform source into target.
+func Diff[T cmp.Ordered](source, target []T) (add, remove []T) {
+	sourceSet := make(map[T]struct{}, len(source))
+	for _, v := range source {
+		sourceSet[v] = struct{}{}
+	}
+	targetSet := make(map[T]struct{}, len(target))
+	for _, v := range target {
+		targetSet[v] = struct{}{}
+	}
+	for _, v := range source {
+		if _, ok := targetSet[v]; !ok {
+			remove = append(remove, v)
+		}
+	}
+	for _, v := range target {
+		if _, ok := sourceSet[v]; !ok {
+			add = append(add, v)
+		}
+	}
 	return
 }
 
 // DiffPolicy diff policy source, target list to get add, remove list
 func DiffPolicy(source, target []*Policy) (add, remove []*Policy) {
-	sourceMap := make(map[any]*Policy)
-	targetMap := make(map[any]*Policy)
+	sourceMap := make(map[string]*Policy, len(source))
+	targetMap := make(map[string]*Policy, len(target))
 	for _, v := range source {
 		sourceMap[v.Key()] = v
 	}

server_check.go

@@ -132,6 +132,7 @@ func objectHierarchyBFS(domain Domain, object Object, fn func(Object, Domain) []
 	hierarchyLevel := 0
 	m := map[uint64]int{object.GetID(): 1}
 	queue := []uint64{object.GetID()}
+	// BFS: queue grows as children are discovered
 	for i := 0; i < len(queue); i++ {
 		node := newByE(object)
 		node.SetID(queue[i])

server_feature_reset.go

@@ -46,22 +46,21 @@ func (s *server) ResetFeature(domain Domain) error {
 }
 
 func getSourceFeatureG2(e IEnforcer, domain Domain) map[string][]string {
-	var queue []string
+	queue := []string{DefaultFeatureRootName}
 	inQueue := map[string]bool{DefaultFeatureRootName: true}
-	for _, v := range queue {
-		inQueue[v] = true
-	}
 
 	m := map[string][]string{}
+	// BFS: queue grows as children are discovered
 	for i := 0; i < len(queue); i++ {
-		m[queue[i]] = []string{}
-		ll := e.GetChildrenForObjectInDomain(&NamedObject{Name: queue[i]}, domain)
+		current := queue[i]
+		m[current] = []string{}
+		ll := e.GetChildrenForObjectInDomain(&NamedObject{Name: current}, domain)
 		for _, v := range ll {
 			if _, ok := inQueue[v.Encode()]; !ok {
 				queue = append(queue, v.Encode())
 				inQueue[v.Encode()] = true
 			}
-			m[queue[i]] = append(m[queue[i]], v.Encode())
+			m[current] = append(m[current], v.Encode())
 		}
 	}
 

server_policy.go

@@ -1,8 +1,5 @@
 package caskin
 
-import (
-	"github.com/ahmetb/go-linq/v3"
-)
 
 // GetPolicy
 // get all policies
@@ -84,7 +81,7 @@ func (s *server) ModifyPolicyPerRole(user User, domain Domain, perRole Role, inp
 	}
 	oid = append(oid, oid1...)
 	oid = append(oid, oid2...)
-	linq.From(oid).Distinct().ToSlice(&oid)
+	oid = distinct(oid)
 	objects, err := s.DB.GetObjectByID(oid)
 	if err != nil {
 		return err

server_user_domain.go

@@ -1,14 +1,12 @@
 package caskin
 
-import "github.com/ahmetb/go-linq/v3"
-
 // GetUserByDomain
 // get all user in domain
 // 1. no permission checking
 func (s *server) GetUserByDomain(domain Domain) ([]User, error) {
 	us := s.Enforcer.GetUsersInDomain(domain)
 	uid := ID(us)
-	linq.From(uid).Distinct().ToSlice(&uid)
+	uid = distinct(uid)
 	return s.DB.GetUserByID(uid)
 }
 
@@ -21,7 +19,7 @@ func (s *server) GetDomainByUser(user User) ([]Domain, error) {
 	}
 	ds := s.Enforcer.GetDomainsIncludeUser(user)
 	did := ID(ds)
-	linq.From(did).Distinct().ToSlice(&did)
+	did = distinct(did)
 	return s.DB.GetDomainByID(did)
 }
 

server_user_role.go

@@ -1,9 +1,5 @@
 package caskin
 
-import (
-	"github.com/ahmetb/go-linq/v3"
-)
-
 // GetUserRole
 // 1. get all user
 // 2. get all role which current user has read permission in current domain
@@ -96,7 +92,7 @@ func (s *server) ModifyUserRolePerUser(user User, domain Domain, perUser User, i
 	var rid []uint64
 	rid = append(rid, rid1...)
 	rid = append(rid, rid2...)
-	linq.From(rid).Distinct().ToSlice(&rid)
+	rid = distinct(rid)
 	roles, err := s.DB.GetRoleByID(rid)
 	if err != nil {
 		return err
@@ -152,7 +148,7 @@ func (s *server) ModifyUserRolePerRole(user User, domain Domain, perRole Role, i
 	var uid []uint64
 	uid = append(uid, uid1...)
 	uid = append(uid, uid2...)
-	linq.From(uid).Distinct().ToSlice(&uid)
+	uid = distinct(uid)
 	users, err := s.DB.GetUserByID(uid)
 	if err != nil {
 		return err