Propellor 3.0 is a major new version with large changes to the API.

Property types have been improved to indicate what systems they target. This prevents using eg, Property FreeBSD on a Debian system.

This forum topic is to help users with the upgrade. Post comments if you're having trouble and Joey will get back to you.

Now, the transition guide as far as your config.hs goes:

• Add props to host definitions.

    host name
        & foo
        & bar
  

  Becomes

    host name $ props
        & foo
        & bar
  

• Similarly, propertyList and combineProperties need props to be used to combine together properties; they no longer accept lists of properties. (If you have such a list, use toProps.)

• And similarly, Chroot, Docker, and Systemd container need props to be used to combine together the properies used inside them.
• The os property is removed. Instead use osDebian, osBuntish, or osFreeBSD. These tell the type checker the target OS of a host.
• GHC needs {-# LANGUAGE TypeOperators #-} to use these fancy types. This is enabled by default for all modules in propellor.cabal. But if you are using propellor as a library, you may need to enable it manually.

Additional things you need to do if you've written your own properties:

• Change Property NoInfo to Property UnixLike
• Change Property HasInfo to Property (HasInfo + UnixLike)
• Change RevertableProperty NoInfo to
  RevertableProperty UnixLike UnixLike
• Change RevertableProperty HasInfo to
  RevertableProperty (HasInfo + UnixLike) UnixLike
• If you know a property only works on a particular OS, like Debian or FreeBSD, use that instead of UnixLike. For example: Property Debian
• It's also possible make a property support a set of OS's, for example: Property (Debian + FreeBSD)
• Removed infoProperty and simpleProperty constructors, instead use property to construct a Property.

• Due to the polymorphic type returned by property, additional type signatures tend to be needed when using it. For example, this will fail to type check, because the type checker cannot guess what type you intend the intermediate property go to have:

    foo :: Property UnixLike
    foo = go `requires` bar
      where
        go = property "foo" (return NoChange)
  

  To fix, specify the type of go:

        go :: Property UnixLike
  

• ensureProperty now needs to be passed a witness to the type of the property it's used in.

    foo = property desc $ ... ensureProperty bar
  

  Becomes

    foo = property' desc $ \w -> ... ensureProperty w bar
  

• General purpose properties like cmdProperty have type Property UnixLike. When using that to run a command only available on Debian, you can tighten the type to only the OS that your more specific property works on. For example:

    upgraded :: Property Debian
    upgraded = tightenTargets (cmdProperty "apt-get" ["upgrade"])
  

• Several utility functions have been renamed:
  getInfo to fromInfo
  propertyInfo to getInfo
  propertyDesc to getDesc
  propertyChildren to getChildren