Detailed steps to reproduce the problem?

https://goplay.tools/snippet/W8-KVVAsohX

package main

import (
	"fmt"

	"go.mongodb.org/mongo-driver/v2/bson"
)

func main() {
	doc := bson.D{{"foo", 123123}}
	raw, _ := bson.Marshal(doc)

	type RT struct {
		Foo bson.Raw
	}
	rt := RT{}
	err := bson.Unmarshal(raw, &rt)

	fmt.Printf("Hello, World! (err: %v; rt: %+v)", err, rt)
}

Output:

Hello, World! (err: <nil>; rt: {Foo:})

In the above, I expect Unmarshal to fail because it’s trying to unmarshal an int32 (123123) into a Raw, which needs to be a document.

Definition of done: what must be done to consider the task complete?

An appropriate error should be returned.

The exact Go version used, with patch level:

1.25.5

The exact version of the Go driver used:

2.4.0

Describe how MongoDB is set up. Local vs Hosted, version, topology, load balanced, etc.

n/a

The operating system and version (e.g. Windows 7, OSX 10.8, ...)

n/a

Security Vulnerabilities

Since this puts the application into an internally-invalid state there could be some security implications here, but I can’t think of an actual vulnerability.