Setup compile commands directory for the clangd extension

package.json

@@ -241,11 +241,12 @@
           "items": {
             "enum": [
               "ms-vscode.cpptools",
+              "llvm-vs-code-extensions.vscode-clangd",
               "rust-lang.rust-analyzer"
             ]
           },
           "default": true,
-          "markdownDescription": "Automatically setup other extensions to use files generated by Meson. Set it to `false` if for example `.vscode/settings.json` is committed into git and should not be modified. It can also be an array of extension IDs of the following:\n- [`ms-vscode.cpptools`](https://marketplace.visualstudio.com/items?itemName=ms-vscode.cpptools)\n- [`rust-lang.rust-analyzer`](https://marketplace.visualstudio.com/items?itemName=rust-lang.rust-analyzer)."
+          "markdownDescription": "Automatically setup other extensions to use files generated by Meson. Set it to `false` if for example `.vscode/settings.json` is committed into git and should not be modified. It can also be an array of extension IDs of the following:\n- [`ms-vscode.cpptools`](https://marketplace.visualstudio.com/items?itemName=ms-vscode.cpptools)\n- [`llvm-vs-code-extensions.vscode-clangd`](https://marketplace.visualstudio.com/items?itemName=llvm-vs-code-extensions.vscode-clangd)\n- [`rust-lang.rust-analyzer`](https://marketplace.visualstudio.com/items?itemName=rust-lang.rust-analyzer)."
         },
         "mesonbuild.Swift-MesonLSP.others.ignoreDiagnosticsFromSubprojects": {
           "type": [

src/extension.ts

@@ -135,9 +135,36 @@ export async function activate(ctx: vscode.ExtensionContext) {
 
   const compileCommandsFile = `${buildDir}/compile_commands.json`;
   whenFileExists(ctx, compileCommandsFile, async () => {
+    const conf = vscode.workspace.getConfiguration();
     if (shouldModifySetting("ms-vscode.cpptools")) {
       const conf = vscode.workspace.getConfiguration("C_Cpp");
-      conf.update("default.compileCommands", compileCommandsFile, vscode.ConfigurationTarget.Workspace);
+      conf.update("C_Cpp.default.compileCommands", compileCommandsFile, vscode.ConfigurationTarget.Workspace);
+    }
+    if (shouldModifySetting("llvm-vs-code-extensions.vscode-clangd")) {
+      let args = undefined;
+      const wanted = `--compile-commands-dir=${buildDir}`;
+      const current = conf.get("clangd.arguments");
+      if (current && Array.isArray(current)) {
+        // if wanted is already in current, leave args undefined to prevent a config update
+        if (!current.includes(wanted)) {
+          const found = current.findIndex((arg) => arg.startsWith("--compile-commands-dir="));
+          if (found !== -1) {
+            current[found] = wanted;
+            args = current;
+          } else {
+            args = [...current, wanted];
+          }
+        }
+      } else {
+        args = [wanted];
+      }
+
+      if (args) {
+        conf.update("clangd.arguments", args, vscode.ConfigurationTarget.Workspace).then(
+          () => vscode.commands.executeCommand("clangd.restart"),
+          () => {},
+        );
+      }
     }
   });
 

src/types.ts

@@ -9,7 +9,10 @@ export type LinterConfiguration = {
 };
 
 export type LanguageServer = "Swift-MesonLSP" | null;
-export type ModifiableExtension = "ms-vscode.cpptools" | "rust-lang.rust-analyzer";
+export type ModifiableExtension =
+  | "ms-vscode.cpptools"
+  | "llvm-vs-code-extensions.vscode-clangd"
+  | "rust-lang.rust-analyzer";
 
 export interface ExtensionConfiguration {
   configureOnOpen: boolean | "ask";