fix: sync typed-nil dependency validation

internal/rpc/router.go

@@ -5,6 +5,7 @@ import (
 	"encoding/hex"
 	"errors"
 	"fmt"
+	"reflect"
 	"sync"
 	"time"
 
@@ -234,6 +235,7 @@ type authUserCacheEntry struct {
 
 // New 创建 Router，由各业务域自行注册其 RPC handler（registerHelp/Auth/Users/Updates）。
 func New(cfg Config, deps Deps, log *zap.Logger, clk clock.Clock) *Router {
+	assertNoTypedNilDeps(deps)
 	instanceID := cfg.InstanceID
 	if instanceID == "" {
 		instanceID = fmt.Sprintf("%016x", randomNonZeroInt64())
@@ -282,6 +284,31 @@ func New(cfg Config, deps Deps, log *zap.Logger, clk clock.Clock) *Router {
 	return r
 }
 
+// assertNoTypedNilDeps rejects partially constructed optional dependencies at
+// the composition boundary. A Go interface containing a nil concrete pointer
+// is not equal to nil, so handler-level availability checks would otherwise
+// admit it and panic only when the first method is invoked.
+//
+// This is an invariant check, not a compatibility fallback: callers must
+// either inject a fully constructed implementation or leave the interface nil.
+func assertNoTypedNilDeps(deps Deps) {
+	value := reflect.ValueOf(deps)
+	typeOfDeps := value.Type()
+	for i := 0; i < value.NumField(); i++ {
+		field := value.Field(i)
+		if field.Kind() != reflect.Interface || field.IsNil() {
+			continue
+		}
+		implementation := field.Elem()
+		switch implementation.Kind() {
+		case reflect.Chan, reflect.Func, reflect.Interface, reflect.Map, reflect.Pointer, reflect.Slice:
+			if implementation.IsNil() {
+				panic(fmt.Sprintf("rpc: dependency %s is a typed nil %s", typeOfDeps.Field(i).Name, implementation.Type()))
+			}
+		}
+	}
+}
+
 func registerRPC[T bin.Object](d *tlprofile.Dispatcher, method tlprofile.SemanticID, handler func(context.Context, T) (any, error)) {
 	if d == nil || handler == nil {
 		panic("rpc: register nil canonical RPC handler or dispatcher")