DL4000 - MAINTAINER is deprecated

Description

The MAINTAINER instruction is obsolete. Declare the image author with LABEL maintainer="name" instead.

Goals

Specification

  1. Walk each top-level instruction in the Dockerfile AST.
  2. If an instruction's keyword equals MAINTAINER (case-insensitive), emit DL4000.
  3. Report the line of the MAINTAINER instruction with the message MAINTAINER is deprecated. Use LABEL maintainer="name" instead.

(c) 2025 Asymmetric Effort, LLC. scaldwell@asymmetric-effort.com Asymmetric Effort logo