anchor.diff:  
   RUN \
     chmod 644 /etc/mysql/my.cnf && \
  -  chown mysql /etc/mysql/my.cnf && \
  +  chown "${MARIADB_USER}":"${MARIADB_GROUP}" /etc/mysql/my.cnf && \
     chmod 644 /etc/mysql/mysqld_charset.cnf && \
  -  chown mysql /etc/mysql/mysqld_charset.cnf && \
  +  chown "${MARIADB_USER}":"${MARIADB_GROUP}" /etc/mysql/mysqld_charset.cnf && \
     chmod 755 docker-entrypoint.sh
   
   EXPOSE 3306
  
positive.code: 
  
  # explicitly set user/group IDs
  RUN addgroup -S "${MARIADB_USER}" -g 9999 && adduser -S -G "${MARIADB_USER}" -u 9999 "${MARIADB_USER}"
  
  RUN \
    set -ex; \
  
negative.code: 
  ENV \
    MARIADB_USER=mysql \
    MARIADB_GROUP=mysql \
    MARIADB_BASE_DIR=/usr \
    MARIADB_DATA_DIR=/var/lib/mysql \
    MARIADB_RUN_DIR=/run/mysqld \
  