fix: resolve im backend issue list regressions

server/store/group_message_runtime_test.go

@@ -2,6 +2,9 @@ package store
 
 import (
 	"context"
+	"encoding/json"
+	"strconv"
+	"strings"
 	"testing"
 	"time"
 
@@ -12,6 +15,7 @@ type testGroupMessageRuntime struct {
 	claims          map[string]*groupMessageUniqueRecord
 	seqs            map[string]int64
 	shortStates     map[string]bool
+	objects         map[string][]byte
 	deletedPrefixes []string
 	deletedObjects  []string
 }
@@ -21,6 +25,7 @@ func newTestGroupMessageRuntime() *testGroupMessageRuntime {
 		claims:      make(map[string]*groupMessageUniqueRecord),
 		seqs:        make(map[string]int64),
 		shortStates: make(map[string]bool),
+		objects:     make(map[string][]byte),
 	}
 }
 
@@ -145,21 +150,37 @@ func (r *testGroupMessageRuntime) StartRealtimeFanoutSubscriber(context.Context,
 	return nil
 }
 
-func (r *testGroupMessageRuntime) CacheObject(types.TenantID, string, string, any) error {
+func (r *testGroupMessageRuntime) CacheObject(tenantID types.TenantID, namespace, id string, value any) error {
+	payload, err := json.Marshal(value)
+	if err != nil {
+		return err
+	}
+	r.objects[strconv.FormatInt(int64(tenantID), 10)+":"+namespace+":"+id] = payload
 	return nil
 }
 
-func (r *testGroupMessageRuntime) GetCachedObject(types.TenantID, string, string, any) (bool, error) {
-	return false, nil
+func (r *testGroupMessageRuntime) GetCachedObject(tenantID types.TenantID, namespace, id string, value any) (bool, error) {
+	payload, ok := r.objects[strconv.FormatInt(int64(tenantID), 10)+":"+namespace+":"+id]
+	if !ok {
+		return false, nil
+	}
+	return true, json.Unmarshal(payload, value)
 }
 
-func (r *testGroupMessageRuntime) DeleteCachedObject(_ types.TenantID, namespace, id string) error {
+func (r *testGroupMessageRuntime) DeleteCachedObject(tenantID types.TenantID, namespace, id string) error {
 	r.deletedObjects = append(r.deletedObjects, namespace+":"+id)
+	delete(r.objects, strconv.FormatInt(int64(tenantID), 10)+":"+namespace+":"+id)
 	return nil
 }
 
-func (r *testGroupMessageRuntime) DeleteCachedObjectsByPrefix(_ types.TenantID, _ string, prefix string) error {
+func (r *testGroupMessageRuntime) DeleteCachedObjectsByPrefix(tenantID types.TenantID, namespace, prefix string) error {
 	r.deletedPrefixes = append(r.deletedPrefixes, prefix)
+	cachePrefix := strconv.FormatInt(int64(tenantID), 10) + ":" + namespace + ":" + prefix
+	for key := range r.objects {
+		if strings.HasPrefix(key, cachePrefix) {
+			delete(r.objects, key)
+		}
+	}
 	return nil
 }
 
@@ -220,6 +241,46 @@ func TestLoginTokenRevocation(t *testing.T) {
 	}
 }
 
+func TestGroupMemberPageCacheRoundTripAndInvalidate(t *testing.T) {
+	oldRuntime := groupMsgRuntime
+	runtime := newTestGroupMessageRuntime()
+	groupMsgRuntime = runtime
+	t.Cleanup(func() { groupMsgRuntime = oldRuntime })
+
+	opts := types.GroupMemberListOptions{
+		Role:        "member",
+		Query:       " alice ",
+		Cursor:      "42",
+		Limit:       20,
+		Mentionable: true,
+	}
+	key := groupMemberPageCacheID("grpAlpha", opts)
+	if !strings.HasPrefix(key, "grpAlpha|") {
+		t.Fatalf("cache key must be topic-prefixed for invalidation: %q", key)
+	}
+	CacheGroupMemberPage(7, key, groupMemberPageCache{
+		Items: []types.GroupMember{{
+			ID:     43,
+			Topic:  "grpAlpha",
+			UserID: types.Uid(100),
+			Role:   types.GroupMemberRoleMember,
+		}},
+		NextCursor: "43",
+	})
+	cached, ok := GetCachedGroupMemberPage(7, key)
+	if !ok || cached.NextCursor != "43" || len(cached.Items) != 1 || cached.Items[0].UserID != types.Uid(100) {
+		t.Fatalf("unexpected cached page: ok=%v page=%#v", ok, cached)
+	}
+
+	invalidateGroupMemberPages(7, "grpAlpha")
+	if _, ok := GetCachedGroupMemberPage(7, key); ok {
+		t.Fatalf("group member page cache survived invalidation")
+	}
+	if len(runtime.deletedPrefixes) != 1 || runtime.deletedPrefixes[0] != "grpAlpha|" {
+		t.Fatalf("unexpected invalidation prefixes: %#v", runtime.deletedPrefixes)
+	}
+}
+
 func TestRealtimeFanoutDedupClaimIDIsNodeScoped(t *testing.T) {
 	tenantID := types.TenantID(7)
 	dedupKey := "data:p2pABC:42"