Make cradle dependencies absolute paths

This patch fixes #1068 when the cabal plugin is not used.

Co-authored-by: Lin Jian <me@linj.tech>

Author: fendor

ghcide-test/data/watched-files/reload/reload.cabal

@@ -0,0 +1,12 @@
+cabal-version:      2.4
+name:               reload
+version:            0.1.0.0
+author:             Lin Jian
+maintainer:         me@linj.tech
+build-type:         Simple
+
+library
+  exposed-modules:  MyLib
+  build-depends:    base
+  hs-source-dirs:   src
+  default-language: Haskell2010

ghcide-test/data/watched-files/reload/src/MyLib.hs

@@ -0,0 +1,6 @@
+module MyLib (someFunc) where
+
+import Data.List.Split
+
+someFunc :: IO ()
+someFunc = putStrLn "someFunc"

ghcide-test/exe/WatchedFileTests.hs

@@ -3,11 +3,14 @@
 
 module WatchedFileTests (tests) where
 
-import           Config                          (testWithDummyPluginEmpty')
+import           Config                          (mkIdeTestFs,
+                                                  testWithDummyPlugin',
+                                                  testWithDummyPluginEmpty')
 import           Control.Applicative.Combinators
 import           Control.Monad.IO.Class          (liftIO)
 import qualified Data.Aeson                      as A
 import qualified Data.Text                       as T
+import qualified Data.Text.IO                    as T
 import           Development.IDE.Test            (expectDiagnostics)
 import           Language.LSP.Protocol.Message
 import           Language.LSP.Protocol.Types     hiding
@@ -18,6 +21,7 @@ import           Language.LSP.Protocol.Types     hiding
 import           Language.LSP.Test
 import           System.Directory
 import           System.FilePath
+import           Test.Hls.FileSystem
 import           Test.Tasty
 import           Test.Tasty.HUnit
 
@@ -69,6 +73,17 @@ tests = testGroup "watched files"
         sendNotification SMethod_WorkspaceDidChangeWatchedFiles $ DidChangeWatchedFilesParams
                [FileEvent (filePathToUri $ sessionDir </> "B.hs") FileChangeType_Changed ]
         expectDiagnostics [("A.hs", [(DiagnosticSeverity_Error, (3, 4), "Couldn't match expected type '()' with actual type 'Int'", Just "GHC-83865")])]
+      , testWithDummyPlugin' "reload HLS after .cabal file changes" (mkIdeTestFs [copyDir ("watched-files" </> "reload")]) $ \sessionDir -> do
+          let hsFile = "src" </> "MyLib.hs"
+          _ <- openDoc hsFile "haskell"
+          expectDiagnostics [(hsFile, [(DiagnosticSeverity_Error, (2, 7), "Could not load module \8216Data.List.Split\8217", Nothing)])]
+          let cabalFile = "reload.cabal"
+          cabalContent <- liftIO $ T.readFile cabalFile
+          let fix = T.replace "build-depends:    base" "build-depends:    base, split"
+          liftIO $ T.writeFile cabalFile (fix cabalContent)
+          sendNotification SMethod_WorkspaceDidChangeWatchedFiles $ DidChangeWatchedFilesParams
+            [ FileEvent (filePathToUri $ sessionDir </> cabalFile) FileChangeType_Changed ]
+          expectDiagnostics [(hsFile, [])]
     ]
   ]
 

ghcide/session-loader/Development/IDE/Session.hs

@@ -698,7 +698,15 @@ loadSessionWithOptions recorder SessionLoadingOptions{..} rootDir que = do
             let ncfp = toNormalizedFilePath' (toAbsolutePath file)
             cachedHieYamlLocation <- HM.lookup ncfp <$> readVar filesMap
             hieYaml <- cradleLoc file
-            sessionOpts (join cachedHieYamlLocation <|> hieYaml, file) `Safe.catch` \e ->
+            let
+              -- Each one of deps will be registered as a FileSystemWatcher in the GhcSession action
+              -- so that we can get a workspace/didChangeWatchedFiles notification when a dep changes.
+              -- The GlobPattern of a FileSystemWatcher can be absolute or relative.
+              -- We use the absolute one because it is supported by more LSP clients.
+              -- Here we make sure deps are absolute and later we use those absolute deps as GlobPattern.
+              absolutePathsCradleDeps (eq, deps)
+                = (eq, fmap toAbsolutePath deps)
+            (absolutePathsCradleDeps <$> sessionOpts (join cachedHieYamlLocation <|> hieYaml, file))  `Safe.catch` \e ->
                 return (([renderPackageSetupException file e], Nothing), maybe [] pure hieYaml)
 
     returnWithVersion $ \file -> do