Unknown component type - panic on access

[Mxrk]

Hi,

Discord "released" a new component type (20) for checkpoints without being listed on https://discord.com/developers/docs/components/reference#component-object-component-types

discordgo/components.go

Lines 77 to 80 in 22e5cd8

	default:
	return fmt.Errorf("unknown component type: %d", v.Type)
	}
	return json.Unmarshal(src, umc.MessageComponent)

Because of the error handling here, it's currently simply returning an error which isn't stopping handlers to work with the event.
That means accessing the event in your handler does end in a panic:

wsapi.go:661:onEvent() error unmarshalling MESSAGE_CREATE event, unknown component type: 20"}
panic: runtime error: invalid memory address or nil pointer dereference

Guess simply removing the return err would fix the problem(?).

[soulnov23]

Hi there! I encountered the same issue and found a workaround if you don't need the Message.Components field.

Here's a simple solution:

Step 1: Clone the repository

git clone https://github.com/bwmarrin/discordgo.git
cd discordgo

Step 2: Remove the custom UnmarshalJSON method

In message.go, delete the entire UnmarshalJSON method (lines 166-183):

// UnmarshalJSON is a helper function to unmarshal the Message.
func (m *Message) UnmarshalJSON(data []byte) error {
    // ... delete this entire function
}

Also remove the "encoding/json" import if it's no longer used.

Step 3: Use a local replace in your project's go.mod

replace github.com/bwmarrin/discordgo => /path/to/your/local/discordgo

Why this works

The Message.Components field already has the json:"-" tag, which means it will be ignored during standard JSON unmarshaling. By removing the custom UnmarshalJSON method, we bypass the component type validation entirely. This way, messages with unknown component types (like the new type 20) won't cause errors.

Trade-off

You won't be able to access the Components field, but if you're not using it, this is a clean solution that prevents the panic.

---

Hope this helps! This should work as a temporary workaround until the library officially supports the new component type.

[Mxrk]

Hi there! I encountered the same issue and found a workaround if you don't need the Message.Components field.

Here's a simple solution:

Step 1: Clone the repository

git clone https://github.com/bwmarrin/discordgo.git
cd discordgo

Step 2: Remove the custom UnmarshalJSON method

In message.go, delete the entire UnmarshalJSON method (lines 166-183):

// UnmarshalJSON is a helper function to unmarshal the Message.
func (m *Message) UnmarshalJSON(data []byte) error {
    // ... delete this entire function
}

Also remove the "encoding/json" import if it's no longer used.

Step 3: Use a local replace in your project's go.mod

replace github.com/bwmarrin/discordgo => /path/to/your/local/discordgo

Why this works

The Message.Components field already has the json:"-" tag, which means it will be ignored during standard JSON unmarshaling. By removing the custom UnmarshalJSON method, we bypass the component type validation entirely. This way, messages with unknown component types (like the new type 20) won't cause errors.

Trade-off

You won't be able to access the Components field, but if you're not using it, this is a clean solution that prevents the panic.

---

Hope this helps! This should work as a temporary workaround until the library officially supports the new component type.

If you just need a workaround, you can check if the .Components object is nil and early return in your handler. That's easier and still supports available components (and you don't have to fork / vendor the lib).