COPY behaviour with --chown is not consistent with docker

[ghost]

Actual behavior When trying to use COPY with --chown and giving an envvar as an argument, build fails, while working perfectly fine in docker 20.10.3.

Expected behavior Image is built correctly while assigning ownership from env variable

To Reproduce Steps to reproduce the behavior:

1. Set up a Dockerfile with ENV and COPY directive
2. COPY something with --chown ${VARNAME}

Additional Information

• Dockerfile Dockerfile-sample.txt

  Triage Notes for the Maintainers

  Description	Yes/No
  Please check if this a new feature you are proposing	- [ ]
  Please check if the build works in docker but not in kaniko	- [x]
  Please check if this error is seen when you use --cache flag	- [ ]
  Please check if your dockerfile is a multistage dockerfile	- [x]

[guillaume-d]

From v1.8.0 onwards this is no longer a syntax error for ADD at least (and COPY should behave similarly).

I did not test if kaniko really sets the owner as expected though, so beware: it might be failing silently now! :roll_eyes:

(Note that this is a dockerfile/1.2.0 feature, which kaniko still does not fully support, see for example https://github.com/GoogleContainerTools/kaniko/issues/1568.)