Merge pull request #114 from erlang-ls/113-show-server-stdout-in-case…

…-of-starting-error

[#113] Show server stdout in case of starting error

client/src/client.ts

@@ -1,5 +1,6 @@
 import * as path from 'path';
-import { workspace, ExtensionContext } from 'vscode';
+import { workspace, ExtensionContext, window } from 'vscode';
+import { spawnSync } from 'child_process';
 
 import {
     LanguageClient,
@@ -30,7 +31,7 @@ export async function get_client(context: ExtensionContext): Promise<LanguageCli
 
     let logLevel = workspace.getConfiguration('erlang_ls').logLevel;
 
-    let serverArgs = [ serverPath, "--transport", "stdio", "--log-level", logLevel ];
+    let serverArgs = [ serverPath, "--log-level", logLevel ];
 
     let logPath = workspace.getConfiguration('erlang_ls').logPath;
     if (logPath !== "") {
@@ -43,10 +44,19 @@ export async function get_client(context: ExtensionContext): Promise<LanguageCli
         transport: TransportKind.stdio
     };
 
+    verifyExecutable(serverPath);
+
     return new LanguageClient(
         'erlang_ls',
         'Erlang LS',
         serverOptions,
         clientOptions
     );
 }
+
+export function verifyExecutable(serverPath: string) {
+    const res = spawnSync(serverPath, ["-version"]);
+    if (res.status !== 0) {
+        window.showErrorMessage('Could not start Language Server. Error: ' + res.stdout);
+    }
+}