Move linters into the tree

This MR moves the GHC linters into the tree, so that they can be run directly using Hadrian.

* Query all files tracked by Git instead of using changed files, so that we can run the exact same linting step locally and in a merge request.
* Only check that the changelogs don't contain TBA when RELEASE=YES.
* Add hadrian/lint script, which runs all the linting steps.
* Ensure the hlint job exits with a failure if hlint is not installed (otherwise we were ignoring the failure). Given that hlint doesn't seem to be available in CI at the moment, I've temporarily allowed failure in the hlint job.
* Run all linting tests in CI using hadrian.

5 files changed, 50 insertions, 11 deletions

diff --git a/hadrian/src/Packages.hs b/hadrian/src/Packages.hs
index a44e3cd95e..9ca18f14c3 100644
--- a/hadrian/src/Packages.hs
+++ b/hadrian/src/Packages.hs
@@ -9,7 +9,9 @@ module Packages (
     hsc2hs, hp2ps, hpc, hpcBin, integerGmp, integerSimple, iserv, iservProxy,
     libffi, libiserv, mtl, parsec, pretty, primitive, process, remoteIserv, rts,
     runGhc, stm, templateHaskell, terminfo, text, time, timeout, touchy,
-    transformers, unlit, unix, win32, xhtml, noteLinter, ghcPackages, isGhcPackage,
+    transformers, unlit, unix, win32, xhtml,
+    lintersCommon, lintNotes, lintCommitMsg, lintSubmoduleRefs, lintWhitespace,
+    ghcPackages, isGhcPackage,
 
     -- * Package information
     programName, nonHsMainPackage, autogenPath, programPath, timeoutPath,
@@ -39,13 +41,25 @@ ghcPackages =
     , hp2ps, hpc, hpcBin, integerGmp, integerSimple, iserv, libffi, libiserv, mtl
     , parsec, pretty, process, rts, runGhc, stm, templateHaskell
     , terminfo, text, time, touchy, transformers, unlit, unix, win32, xhtml
-    , timeout, noteLinter ]
+    , timeout
+    , lintersCommon
+    , lintNotes, lintCommitMsg, lintSubmoduleRefs, lintWhitespace ]
 
 -- TODO: Optimise by switching to sets of packages.
 isGhcPackage :: Package -> Bool
 isGhcPackage = (`elem` ghcPackages)
 
 -- | Package definitions, see 'Package'.
+array, base, binary, bytestring, cabalSyntax, cabal, checkPpr, checkExact, countDeps,
+  compareSizes, compiler, containers, deepseq, deriveConstants, directory,
+  exceptions, filepath, genapply, genprimopcode, ghc, ghcBignum, ghcBoot, ghcBootTh,
+  ghcCompact, ghcHeap, ghci, ghciWrapper, ghcPkg, ghcPrim, haddock, haskeline, hsc2hs,
+  hp2ps, hpc, hpcBin, integerGmp, integerSimple, iserv, iservProxy, remoteIserv, libffi, libiserv, mtl,
+  parsec, pretty, primitive, process, rts, runGhc, stm, templateHaskell,
+  terminfo, text, time, touchy, transformers, unlit, unix, win32, xhtml,
+  timeout,
+  lintersCommon, lintNotes, lintCommitMsg, lintSubmoduleRefs, lintWhitespace
+    :: Package
 array               = lib  "array"
 base                = lib  "base"
 binary              = lib  "binary"
@@ -108,7 +122,12 @@ unlit               = util "unlit"
 unix                = lib  "unix"
 win32               = lib  "Win32"
 xhtml               = lib  "xhtml"
-noteLinter          = prg  "notes-util"      `setPath` "utils/notes-util"
+
+lintersCommon       = lib     "linters-common"      `setPath` "linters/linters-common"
+lintNotes           = linter  "lint-notes"
+lintCommitMsg       = linter  "lint-commit-msg"
+lintSubmoduleRefs   = linter  "lint-submodule-refs"
+lintWhitespace      = linter  "lint-whitespace"
 
 -- | Construct a library package, e.g. @array@.
 lib :: PackageName -> Package
@@ -126,6 +145,10 @@ prg name = program name name
 util :: PackageName -> Package
 util name = program name ("utils" -/- name)
 
+-- | Construct a linter executable program (lives in the \"linters\" subdirectory).
+linter :: PackageName -> Package
+linter name = program name ("linters" -/- name)
+
 -- | Amend a package path if it doesn't conform to a typical pattern.
 setPath :: Package -> FilePath -> Package
 setPath pkg path = pkg { pkgPath = path }
diff --git a/hadrian/src/Rules/Docspec.hs b/hadrian/src/Rules/Docspec.hs
index 69b49a1cc5..30f6a039eb 100644
--- a/hadrian/src/Rules/Docspec.hs
+++ b/hadrian/src/Rules/Docspec.hs
@@ -8,6 +8,7 @@ import Base
 import Context.Path
 import Settings.Builders.Common
 import qualified Packages as P
+import System.Exit (exitFailure)
 
 docspecRules :: Rules ()
 docspecRules = do
@@ -21,8 +22,9 @@ docspec lintAction = do
     putBuild "| Running cabal-docspec…"
     lintAction
     putSuccess "| Done."
-  else
+  else do
     putFailure "| Please make sure you have the `cabal-docspec` executable in your $PATH"
+    liftIO exitFailure
 
 base :: Action ()
 base = do
diff --git a/hadrian/src/Rules/Lint.hs b/hadrian/src/Rules/Lint.hs
index bb7df1687a..58f9715f21 100644
--- a/hadrian/src/Rules/Lint.hs
+++ b/hadrian/src/Rules/Lint.hs
@@ -5,6 +5,7 @@ module Rules.Lint
 import Base
 import Settings.Builders.Common
 import System.Directory (findExecutable)
+import System.Exit (exitFailure)
 
 lintRules :: Rules ()
 lintRules = do
@@ -19,8 +20,9 @@ lint lintAction = do
     putBuild "| Running the linter…"
     lintAction
     putSuccess "| Done."
-  else
+  else do
     putFailure "| Please make sure you have the `hlint` executable in your $PATH"
+    liftIO exitFailure
 
 runHLint :: [FilePath] -- ^ include directories
          -> [String]   -- ^ CPP defines
diff --git a/hadrian/src/Rules/Test.hs b/hadrian/src/Rules/Test.hs
index fe0aba04cc..4b0ba4a913 100644
--- a/hadrian/src/Rules/Test.hs
+++ b/hadrian/src/Rules/Test.hs
@@ -44,17 +44,24 @@ countDepsExtra :: Maybe String
 countDepsExtra = Just "-iutils/count-deps"
 
 noteLinterProgPath, noteLinterSourcePath :: FilePath
-noteLinterProgPath = "test/bin/notes-util" <.> exe
-noteLinterSourcePath = "utils/notes-util/Main.hs"
+noteLinterProgPath = "test/bin/lint-notes" <.> exe
+noteLinterSourcePath = "linters/lint-notes/Main.hs"
 noteLinterExtra :: Maybe String
-noteLinterExtra = Just "-iutils/notes-util"
+noteLinterExtra = Just "-ilinters/lint-notes"
+
+whitespaceLinterProgPath, whitespaceLinterSourcePath :: FilePath
+whitespaceLinterProgPath = "test/bin/lint-whitespace" <.> exe
+whitespaceLinterSourcePath = "linters/lint-whitespace/Main.hs"
+whitespaceLinterExtra :: Maybe String
+whitespaceLinterExtra = Just "-ilinters/lint-whitespace"
 
 checkPrograms :: [(String,FilePath, FilePath, Maybe String, Package, Stage -> Stage)]
 checkPrograms =
     [ ("test:check-ppr",checkPprProgPath, checkPprSourcePath, checkPprExtra, checkPpr, id)
     , ("test:check-exact",checkExactProgPath, checkExactSourcePath, checkExactExtra, checkExact, id)
     , ("test:count-deps",countDepsProgPath, countDepsSourcePath, countDepsExtra, countDeps, id)
-    , ("lint:notes-util", noteLinterProgPath, noteLinterSourcePath, noteLinterExtra, noteLinter, const Stage0)
+    , ("lint:notes", noteLinterProgPath, noteLinterSourcePath, noteLinterExtra, lintNotes, const Stage0)
+    , ("lint:whitespace", whitespaceLinterProgPath, whitespaceLinterSourcePath, whitespaceLinterExtra, lintWhitespace, const Stage0)
     ]
 
 inTreeOutTree :: (Stage -> Action b) -> Action b -> Action b
@@ -213,7 +220,8 @@ testRules = do
             setEnv "CHECK_PPR" (top -/- root -/- checkPprProgPath)
             setEnv "CHECK_EXACT" (top -/- root -/- checkExactProgPath)
             setEnv "COUNT_DEPS" (top -/- root -/- countDepsProgPath)
-            setEnv "NOTES_UTIL" (top -/- root -/- noteLinterProgPath)
+            setEnv "LINT_NOTES" (top -/- root -/- noteLinterProgPath)
+            setEnv "LINT_WHITESPACE" (top -/- root -/- whitespaceLinterProgPath)
 
             -- This lets us bypass the need to generate a config
             -- through Make, which happens in testsuite/mk/boilerplate.mk
diff --git a/hadrian/src/Settings/Default.hs b/hadrian/src/Settings/Default.hs
index 8c490347b9..21ab008cb7 100644
--- a/hadrian/src/Settings/Default.hs
+++ b/hadrian/src/Settings/Default.hs
@@ -87,7 +87,11 @@ stage0Packages = do
              , text
              , transformers
              , unlit
-             , noteLinter
+             , lintersCommon
+             , lintNotes
+             , lintCommitMsg
+             , lintSubmoduleRefs
+             , lintWhitespace
              ]
           ++ [ terminfo | not windowsHost, not cross ]
           ++ [ timeout  | windowsHost                ]