Add clangd debugging flags

Author: thomasjm

modules/kernels/cpp/default.nix

@@ -24,7 +24,10 @@ let
   common = callPackage ../common.nix {};
 
   languageServers = lib.optionals settings.lsp.clangd.enable
-    [(callPackage ./language_server_clangd { inherit kernelName llvmPackages system cling; })];
+    [(callPackage ./language_server_clangd {
+      inherit kernelName llvmPackages system cling;
+      settings = settings.lsp.clangd;
+    })];
 
   displaySuffix = {
     "c++17" = " 17";

modules/kernels/cpp/language_server_clangd/default.nix

@@ -7,6 +7,7 @@
 , cling
 
 , kernelName
+, settings
 }:
 
 let
@@ -45,6 +46,9 @@ common.writeTextDirWithMetaAndPassthru clangd.meta passthru "lib/codedown/langua
   args = [
     "${cnls-wrapped}/bin/cpp-notebook-language-server"
     "--wrapped-server" "${clangd}/bin/clangd"
-  ];
+  ]
+  ++ lib.optionals settings.debug ["--log-level" "debug"]
+  ++ lib.optionals settings.super-debug ["--debug-client-writes" "--debug-client-reads" "--debug-server-writes" "--debug-server-reads"]
+  ;
   language_id = "cpp";
 }])

modules/kernels/cpp/module.nix

@@ -63,6 +63,16 @@ in
         type = types.bool;
         default = true;
       };
+      lsp.clangd.debug = mkOption {
+        example = "Clangd: enable debug output";
+        type = types.bool;
+        default = false;
+      };
+      lsp.clangd.super-debug = mkOption {
+        example = "Clangd: enable verbose debug output";
+        type = types.bool;
+        default = false;
+      };
     };
   };
 

tests/app/Spec/Tests/Cpp.hs

@@ -59,6 +59,8 @@ kernelSpecWithLsp :: Text -> NixKernelSpec
 kernelSpecWithLsp flavor = kernelSpec' [
   [i|flavor = "#{flavor}"|]
   , "lsp.clangd.enable = true"
+  , "lsp.clangd.debug = true"
+  -- , "lsp.clangd.super-debug = true"
   ]
 
 kernelSpec' :: [Text] -> NixKernelSpec