Content that comes after a JSON's closing bracket should be ignored

[rcjsuen]

The following Dockerfile can be built by Docker but the validator will flag it with an error because of the extra argument after the closing bracket.

FROM alpine
SHELL [ "bin/sh" ] ]

$ dockerfile-utils lint Dockerfile
Line: 2
SHELL [ "bin/sh" ] ]
      ^^^^^^^^^^^^^^
Error: SHELL requires the arguments to be in JSON form

$ docker build .
Sending build context to Docker daemon  1.695MB
Step 1/2 : FROM alpine
 ---> 3fd9065eaf02
Step 2/2 : SHELL [ "bin/sh" ] ]
 ---> Running in b0da3c65034a
Removing intermediate container b0da3c65034a
 ---> aa065d62e762
Successfully built aa065d62e762