previously docker did import environment variables if they were present
but created them if they were not when it was asked via a --env-file
cli option to import but not create them.
fix is to only import the variable into the environment if it is present.
additionally do not import variable names of zero-length (which are lines
w/ a potential variable definition w/o a variable name).
refs:
- https://github.com/docker/for-linux/issues/284
Signed-off-by: Tom Klingenberg <tklingenberg@lastflood.net>
Upstream-commit: 96c026eb30
Component: cli
`--label-file` has the exact same behavior as `--env-file`, meaning any
placeholder (i.e. a simple key, no `=` sign, no value), it will get the
value from the environment variable.
For `--label-file` it should just add an empty label.
Signed-off-by: Vincent Demeester <vincent@sbr.pm>
Upstream-commit: 2b17f4c8a8
Component: cli
