[raeperd]

Why

encoding/json/v2 is stable in Go 1.27 (blog) and adds the UnmarshalerFrom interface:

UnmarshalJSONFrom(*jsontext.Decoder) error

Like UnmarshalJSON, it must use a pointer receiver. A value-receiver type that adopts it is reported today, while the same type with UnmarshalJSON is not:

type T struct{ N int }

func (t T) Get() int                                     { return t.N }
func (t *T) UnmarshalJSONFrom(d *jsontext.Decoder) error { ... }
// the methods of "T" use pointer receiver and non-pointer receiver.

What

• Add *.UnmarshalJSONFrom to the built-in exclusions.
• Add a JSONV2 type to the builtinmethods and disablebuiltin testdata. It uses local stand-ins for the jsontext types, so go.mod stays at go 1.26.0.
• README: list the new exclusion and fix the config comment, which said MarshalJSON instead of UnmarshalJSON.

MarshalJSONTo is not excluded, the same as MarshalJSON.

Test

• go test -race . passes, and golangci-lint run reports 0 issues.
• With the analyzer.go change reverted, builtinmethods fails with an unexpected diagnostic on JSONV2.

[ldez]

LGTM