Some fixes for 9.2

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

@@ -729,7 +729,17 @@ emptyHscEnv :: IORef NameCache -> FilePath -> IO HscEnv
 #endif
 emptyHscEnv nc libDir = do
     -- We call setSessionDynFlags so that the loader is initialised
-    env <- runGhc (Just libDir) $ getSessionDynFlags >>= setSessionDynFlags >> getSession
+    -- We need to do this before we call initUnits.
+    -- However, on GHC 9.2 calling setSessionDynFlags too early
+    -- can mess up the package db cache for some reason.
+    -- So on 9.2 the loader is initialised by the call to setSessionDynFlags
+    -- only after we actually have a proper set of DynFlags
+    env <- runGhc (Just libDir) $
+#if MIN_VERSION_ghc(9,3,0)
+      getSessionDynFlags >>= setSessionDynFlags >> getSession
+#else
+      getSession
+#endif
     pure $ setNameCache nc (hscSetFlags ((hsc_dflags env){useUnicode = True }) env)
 
 data TargetDetails = TargetDetails
@@ -824,20 +834,6 @@ newComponentCache recorder exts cradlePath _cfp hsc_env old_cis new_cis = do
 #else
     do
 #endif
-        -- Whenever we spin up a session on Linux, dynamically load libm.so.6
-        -- in. We need this in case the binary is statically linked, in which
-        -- case the interactive session will fail when trying to load
-        -- ghc-prim, which happens whenever Template Haskell is being
-        -- evaluated or haskell-language-server's eval plugin tries to run
-        -- some code. If the binary is dynamically linked, then this will have
-        -- no effect.
-        -- See https://github.com/haskell/haskell-language-server/issues/221
-        when (os == "linux") $ do
-          initObjLinker hscEnv'
-          res <- loadDLL hscEnv' "libm.so.6"
-          case res of
-            Nothing  -> pure ()
-            Just err -> logWith recorder Error $ LogDLLLoadError err
 
         forM (Map.elems cis) $ \ci -> do
           let df = componentDynFlags ci
@@ -856,10 +852,26 @@ newComponentCache recorder exts cradlePath _cfp hsc_env old_cis new_cis = do
                 -- which we need for any changes to the package flags in the dynflags
                 -- to be visible.
                 -- See #2693
-                evalGhcEnv hsc_env $ do
+                evalGhcEnv hscEnv' $ do
                   _ <- setSessionDynFlags df
                   getSession
 #endif
+          -- Whenever we spin up a session on Linux, dynamically load libm.so.6
+          -- in. We need this in case the binary is statically linked, in which
+          -- case the interactive session will fail when trying to load
+          -- ghc-prim, which happens whenever Template Haskell is being
+          -- evaluated or haskell-language-server's eval plugin tries to run
+          -- some code. If the binary is dynamically linked, then this will have
+          -- no effect.
+          -- See https://github.com/haskell/haskell-language-server/issues/221
+          -- We need to do this after the call to setSessionDynFlags initialises
+          -- the loader
+          when (os == "linux") $ do
+            initObjLinker thisEnv
+            res <- loadDLL thisEnv "libm.so.6"
+            case res of
+              Nothing  -> pure ()
+              Just err -> logWith recorder Error $ LogDLLLoadError err
           henv <- createHscEnvEq thisEnv (zip uids dfs)
           let targetEnv = ([], Just henv)
               targetDepends = componentDependencyInfo ci