type safe targets for properties

  * Property types have been improved to indicate what systems they target.
    This prevents using eg, Property FreeBSD on a Debian system.
    Transition guide for this sweeping API change:
    - Change "host name & foo & bar"
      to     "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.
    - 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"
    - 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.
    - 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.
      change this:  foo = property desc $ ... ensureProperty bar
      to this:      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
  * The new `pickOS` property combinator can be used to combine different
    properties, supporting different OS's, into one Property that chooses
    which to use based on the Host's OS.
  * Re-enabled -O0 in propellor.cabal to reign in ghc's memory use handling
    these complex new types.
  * Added dependency on concurrent-output; removed embedded copy.

1 files changed, 12 insertions, 11 deletions

diff --git a/src/Propellor/Property/Git.hs b/src/Propellor/Property/Git.hs
index a5ef5ab1..5d7c8b4d 100644
--- a/src/Propellor/Property/Git.hs
+++ b/src/Propellor/Property/Git.hs
@@ -11,7 +11,7 @@ import Data.List
 -- using git-daemon, run from inetd.
 --
 -- Note that reverting this property does not remove or stop inetd.
-daemonRunning :: FilePath -> RevertableProperty NoInfo
+daemonRunning :: FilePath -> RevertableProperty DebianLike DebianLike
 daemonRunning exportdir = setup <!> unsetup
   where
 	setup = containsLine conf (mkl "tcp4")
@@ -47,7 +47,7 @@ daemonRunning exportdir = setup <!> unsetup
 		, exportdir
 		]
 
-installed :: Property NoInfo
+installed :: Property DebianLike
 installed = Apt.installed ["git"]
 
 type RepoUrl = String
@@ -61,8 +61,8 @@ type Branch = String
 -- it will be recursively deleted first.
 --
 -- A branch can be specified, to check out.
-cloned :: User -> RepoUrl -> FilePath -> Maybe Branch -> Property NoInfo
-cloned owner url dir mbranch = check originurl (property desc checkout)
+cloned :: User -> RepoUrl -> FilePath -> Maybe Branch -> Property DebianLike
+cloned owner url dir mbranch = check originurl go
 	`requires` installed
   where
 	desc = "git cloned " ++ url ++ " to " ++ dir
@@ -74,12 +74,13 @@ cloned owner url dir mbranch = check originurl (property desc checkout)
 			return (v /= Just url)
 		, return True
 		)
-	checkout = do
+	go :: Property DebianLike
+	go = property' desc $ \w -> do
 		liftIO $ do
 			whenM (doesDirectoryExist dir) $
 				removeDirectoryRecursive dir
 			createDirectoryIfMissing True (takeDirectory dir)
-		ensureProperty $ userScriptProperty owner (catMaybes checkoutcmds)
+		ensureProperty w $ userScriptProperty owner (catMaybes checkoutcmds)
 			`assume` MadeChange
 	checkoutcmds = 
 		-- The </dev/null fixes an intermittent
@@ -99,8 +100,8 @@ isGitDir dir = isNothing <$> catchMaybeIO (readProcess "git" ["rev-parse", "--re
 
 data GitShared = Shared Group | SharedAll | NotShared
 
-bareRepo :: FilePath -> User -> GitShared -> Property NoInfo
-bareRepo repo user gitshared = check (isRepo repo) $ propertyList ("git repo: " ++ repo) $
+bareRepo :: FilePath -> User -> GitShared -> Property UnixLike
+bareRepo repo user gitshared = check (isRepo repo) $ propertyList ("git repo: " ++ repo) $ toProps $
 	dirExists repo : case gitshared of
 		NotShared ->
 			[ ownerGroup repo user (userGroup user)
@@ -121,7 +122,7 @@ bareRepo repo user gitshared = check (isRepo repo) $ propertyList ("git repo: "
 	isRepo repo' = isNothing <$> catchMaybeIO (readProcess "git" ["rev-parse", "--resolve-git-dir", repo'])
 
 -- | Set a key value pair in a git repo's configuration.
-repoConfigured :: FilePath -> (String, String) -> Property NoInfo
+repoConfigured :: FilePath -> (String, String) -> Property UnixLike
 repo `repoConfigured` (key, value) = check (not <$> alreadyconfigured) $
 	userScriptProperty (User "root")
 		[ "cd " ++ repo
@@ -141,7 +142,7 @@ getRepoConfig repo key = catchDefaultIO [] $
 	lines <$> readProcess "git" ["-C", repo, "config", key]
 
 -- | Whether a repo accepts non-fast-forward pushes.
-repoAcceptsNonFFs :: FilePath -> RevertableProperty NoInfo
+repoAcceptsNonFFs :: FilePath -> RevertableProperty UnixLike UnixLike
 repoAcceptsNonFFs repo = accepts <!> refuses
   where
 	accepts = repoConfigured repo ("receive.denyNonFastForwards", "false")
@@ -152,7 +153,7 @@ repoAcceptsNonFFs repo = accepts <!> refuses
 
 -- | Sets a bare repository's default branch, which will be checked out
 -- when cloning it.
-bareRepoDefaultBranch :: FilePath -> String -> Property NoInfo
+bareRepoDefaultBranch :: FilePath -> String -> Property UnixLike
 bareRepoDefaultBranch repo branch =
 	userScriptProperty (User "root")
 		[ "cd " ++ repo