go-kratos/kratos · error

container.group: can't assign a nil to the new function

Error message

container.group: can't assign a nil to the new function

What it means

Error "container.group: can't assign a nil to the new function" thrown in go-kratos/kratos.

Source

Thrown at internal/group/group.go:21

// And it will cache all the objects to reduce the creation of object.
package group

import "sync"

// Factory is a function that creates an object of type T.
type Factory[T any] func() T

// Group is a lazy load container.
type Group[T any] struct {
	factory func() T
	vals    map[string]T
	sync.RWMutex
}

// NewGroup news a group container.
func NewGroup[T any](factory Factory[T]) *Group[T] {
	if factory == nil {
		panic("container.group: can't assign a nil to the new function")
	}
	return &Group[T]{
		factory: factory,
		vals:    make(map[string]T),
	}
}

// Get gets the object by the given key.
func (g *Group[T]) Get(key string) T {
	g.RLock()
	v, ok := g.vals[key]
	if ok {
		g.RUnlock()
		return v
	}
	g.RUnlock()

	// slow path for group don`t have specified key value

View on GitHub (pinned to 668db92c2c)

When it happens

Trigger: Thrown at internal/group/group.go:21 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of go-kratos/kratos@668db92c2c (2026-08-16). Data as JSON: /api/errors/d53e3983f1195363. Report an issue: GitHub.