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, 25 insertions, 24 deletions

diff --git a/src/Propellor/Property/File.hs b/src/Propellor/Property/File.hs
index 3021617c..e072fcaa 100644
--- a/src/Propellor/Property/File.hs
+++ b/src/Propellor/Property/File.hs
@@ -9,14 +9,14 @@ import System.Exit
 type Line = String
 
 -- | Replaces all the content of a file.
-hasContent :: FilePath -> [Line] -> Property NoInfo
+hasContent :: FilePath -> [Line] -> Property UnixLike
 f `hasContent` newcontent = fileProperty
 	("replace " ++ f)
 	(\_oldcontent -> newcontent) f
 
 -- | Replaces all the content of a file, ensuring that its modes do not
 -- allow it to be read or written by anyone other than the current user
-hasContentProtected :: FilePath -> [Line] -> Property NoInfo
+hasContentProtected :: FilePath -> [Line] -> Property UnixLike
 f `hasContentProtected` newcontent = fileProperty' writeFileProtected 
 	("replace " ++ f)
 	(\_oldcontent -> newcontent) f
@@ -25,38 +25,38 @@ f `hasContentProtected` newcontent = fileProperty' writeFileProtected
 --
 -- The file's permissions are preserved if the file already existed.
 -- Otherwise, they're set to 600.
-hasPrivContent :: IsContext c => FilePath -> c -> Property HasInfo
+hasPrivContent :: IsContext c => FilePath -> c -> Property (HasInfo + UnixLike)
 hasPrivContent f = hasPrivContentFrom (PrivDataSourceFile (PrivFile f) f) f
 
 -- | Like hasPrivContent, but allows specifying a source
 -- for PrivData, rather than using PrivDataSourceFile .
-hasPrivContentFrom :: (IsContext c, IsPrivDataSource s) => s -> FilePath -> c -> Property HasInfo
+hasPrivContentFrom :: (IsContext c, IsPrivDataSource s) => s -> FilePath -> c -> Property (HasInfo + UnixLike)
 hasPrivContentFrom = hasPrivContent' writeFileProtected
 
 -- | Leaves the file at its default or current mode,
 -- allowing "private" data to be read.
 --
 -- Use with caution!
-hasPrivContentExposed :: IsContext c => FilePath -> c -> Property HasInfo
+hasPrivContentExposed :: IsContext c => FilePath -> c -> Property (HasInfo + UnixLike)
 hasPrivContentExposed f = hasPrivContentExposedFrom (PrivDataSourceFile (PrivFile f) f) f
 
-hasPrivContentExposedFrom :: (IsContext c, IsPrivDataSource s) => s -> FilePath -> c -> Property HasInfo
+hasPrivContentExposedFrom :: (IsContext c, IsPrivDataSource s) => s -> FilePath -> c -> Property (HasInfo + UnixLike)
 hasPrivContentExposedFrom = hasPrivContent' writeFile
 
-hasPrivContent' :: (IsContext c, IsPrivDataSource s) => (FilePath -> String -> IO ()) -> s -> FilePath -> c -> Property HasInfo
+hasPrivContent' :: (IsContext c, IsPrivDataSource s) => (FilePath -> String -> IO ()) -> s -> FilePath -> c -> Property (HasInfo + UnixLike)
 hasPrivContent' writer source f context = 
 	withPrivData source context $ \getcontent -> 
-		property desc $ getcontent $ \privcontent -> 
-			ensureProperty $ fileProperty' writer desc
+		property' desc $ \o -> getcontent $ \privcontent -> 
+			ensureProperty o $ fileProperty' writer desc
 				(\_oldcontent -> privDataLines privcontent) f
   where
 	desc = "privcontent " ++ f
 
 -- | Ensures that a line is present in a file, adding it to the end if not.
-containsLine :: FilePath -> Line -> Property NoInfo
+containsLine :: FilePath -> Line -> Property UnixLike
 f `containsLine` l = f `containsLines` [l]
 
-containsLines :: FilePath -> [Line] -> Property NoInfo
+containsLines :: FilePath -> [Line] -> Property UnixLike
 f `containsLines` ls = fileProperty (f ++ " contains:" ++ show ls) go f
   where
 	go content = content ++ filter (`notElem` content) ls
@@ -64,27 +64,28 @@ f `containsLines` ls = fileProperty (f ++ " contains:" ++ show ls) go f
 -- | Ensures that a line is not present in a file.
 -- Note that the file is ensured to exist, so if it doesn't, an empty
 -- file will be written.
-lacksLine :: FilePath -> Line -> Property NoInfo
+lacksLine :: FilePath -> Line -> Property UnixLike
 f `lacksLine` l = fileProperty (f ++ " remove: " ++ l) (filter (/= l)) f
 
-lacksLines :: FilePath -> [Line] -> Property NoInfo
+lacksLines :: FilePath -> [Line] -> Property UnixLike
 f `lacksLines` ls = fileProperty (f ++ " remove: " ++ show [ls]) (filter (`notElem` ls)) f
 
 -- | Replaces the content of a file with the transformed content of another file
-basedOn :: FilePath -> (FilePath, [Line] -> [Line]) -> Property NoInfo
-f `basedOn` (f', a) = property desc $ go =<< (liftIO $ readFile f')
+basedOn :: FilePath -> (FilePath, [Line] -> [Line]) -> Property UnixLike
+f `basedOn` (f', a) = property' desc $ \o -> do
+	tmpl <- liftIO $ readFile f'
+	ensureProperty o $ fileProperty desc (\_ -> a $ lines $ tmpl) f
   where
 	desc = "replace " ++ f
-	go tmpl = ensureProperty $ fileProperty desc (\_ -> a $ lines $ tmpl) f
 
 -- | Removes a file. Does not remove symlinks or non-plain-files.
-notPresent :: FilePath -> Property NoInfo
+notPresent :: FilePath -> Property UnixLike
 notPresent f = check (doesFileExist f) $ property (f ++ " not present") $ 
 	makeChange $ nukeFile f
 
-fileProperty :: Desc -> ([Line] -> [Line]) -> FilePath -> Property NoInfo
+fileProperty :: Desc -> ([Line] -> [Line]) -> FilePath -> Property UnixLike
 fileProperty = fileProperty' writeFile
-fileProperty' :: (FilePath -> String -> IO ()) -> Desc -> ([Line] -> [Line]) -> FilePath -> Property NoInfo
+fileProperty' :: (FilePath -> String -> IO ()) -> Desc -> ([Line] -> [Line]) -> FilePath -> Property UnixLike
 fileProperty' writer desc a f = property desc $ go =<< liftIO (doesFileExist f)
   where
 	go True = do
@@ -103,7 +104,7 @@ fileProperty' writer desc a f = property desc $ go =<< liftIO (doesFileExist f)
 		setOwnerAndGroup f' (fileOwner s) (fileGroup s)
 
 -- | Ensures a directory exists.
-dirExists :: FilePath -> Property NoInfo
+dirExists :: FilePath -> Property UnixLike
 dirExists d = check (not <$> doesDirectoryExist d) $ property (d ++ " exists") $
 	makeChange $ createDirectoryIfMissing True d
 
@@ -113,7 +114,7 @@ newtype LinkTarget = LinkTarget FilePath
 -- | Creates or atomically updates a symbolic link.
 --
 -- Does not overwrite regular files or directories.
-isSymlinkedTo :: FilePath -> LinkTarget -> Property NoInfo
+isSymlinkedTo :: FilePath -> LinkTarget -> Property UnixLike
 link `isSymlinkedTo` (LinkTarget target) = property desc $
 	go =<< (liftIO $ tryIO $ getSymbolicLinkStatus link)
   where
@@ -135,7 +136,7 @@ link `isSymlinkedTo` (LinkTarget target) = property desc $
 	updateLink = createSymbolicLink target `viaStableTmp` link
 
 -- | Ensures that a file is a copy of another (regular) file.
-isCopyOf :: FilePath -> FilePath -> Property NoInfo
+isCopyOf :: FilePath -> FilePath -> Property UnixLike
 f `isCopyOf` f' = property desc $ go =<< (liftIO $ tryIO $ getFileStatus f')
   where
 	desc = f ++ " is copy of " ++ f'
@@ -156,7 +157,7 @@ f `isCopyOf` f' = property desc $ go =<< (liftIO $ tryIO $ getFileStatus f')
 		[Param "--preserve=all", Param "--", File src, File dest]
 
 -- | Ensures that a file/dir has the specified owner and group.
-ownerGroup :: FilePath -> User -> Group -> Property NoInfo
+ownerGroup :: FilePath -> User -> Group -> Property UnixLike
 ownerGroup f (User owner) (Group group) = p `describe` (f ++ " owner " ++ og)
   where
 	p = cmdProperty "chown" [og, f]
@@ -164,7 +165,7 @@ ownerGroup f (User owner) (Group group) = p `describe` (f ++ " owner " ++ og)
 	og = owner ++ ":" ++ group
 
 -- | Ensures that a file/dir has the specfied mode.
-mode :: FilePath -> FileMode -> Property NoInfo
+mode :: FilePath -> FileMode -> Property UnixLike
 mode f v = p `changesFile` f
   where
 	p = property (f ++ " mode " ++ show v) $ do