These were found using `git grep -nE '[^-a-zA-Z0-9<>]-[a-zA-Z0-9]{2}'` (fair warning: _many_ false positives there).
Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
This changes the way onbuild works:
- forbids the chaining of onbuild instructions
- forbids the use of `onbuild from`
- forbids the use of `onbuild maintainer`
It also makes docker throw errors when encountering such triggers when
executing the triggers during `FROM`.
Three tests have been added:
- ensure that chained onbuild (`onbuild onbuild`) is forbidden
- ensure that `onbuild from` is forbidden
- ensure that `onbuild maintainer` is forbidden
Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)