Patch HLS 2.6 to work around performance bug (#941)

haskell/haskell-language-server#4046 (comment)

Author: amesgen

nix/ghcide-workaround.diff

@@ -0,0 +1,13 @@
+diff --git a/session-loader/Development/IDE/Session.hs b/session-loader/Development/IDE/Session.hs
+index bdd27f3d..2639631d 100644
+--- a/session-loader/Development/IDE/Session.hs
++++ b/session-loader/Development/IDE/Session.hs
+@@ -880,7 +880,7 @@ newComponentCache recorder exts cradlePath _cfp hsc_env old_cis new_cis = do
+               getSession
+ #endif
+       henv <- createHscEnvEq thisEnv (zip uids dfs)
+-      let targetEnv = (if isBad ci then multi_errs else [], Just henv)
++      let targetEnv = ([], Just henv)
+           targetDepends = componentDependencyInfo ci
+           res = ( targetEnv, targetDepends)
+       logWith recorder Debug $ LogNewComponentCache res

nix/shell.nix

@@ -25,6 +25,12 @@ hsPkgs.shellFor {
     haskell-language-server = {
       src = inputs.haskellNix.inputs."hls-2.6";
       configureArgs = "--disable-benchmarks --disable-tests";
+      modules = [{
+        packages.ghcide.patches = [
+          # https://github.com/haskell/haskell-language-server/issues/4046#issuecomment-1926242056
+          ./ghcide-workaround.diff
+        ];
+      }];
     };
   };