Avoid gopls crash due to -trace flag #2459

README.md

@@ -91,7 +91,8 @@ Below are the settings you can use to control the use of the language server. Yo
 
 - Set `go.useLanguageServer` to `true` to enable the use of language server
 - Use the setting `go.languageServerExperimentalFeatures` to control which features do you want to be powered by the language server.
-- Set `"go.languageServerFlags": ["-logfile", "path to a text file that exists"]` to collect traces in a log file.
+- Set `"go.languageServerFlags": ["-logfile", "path to a text file that exists"]` to collect logs in a log file.
+- Set `"go.languageServerFlags": ["-rpc.trace"]` to see the complete rpc trace in the output panel (`View` -> `Output` -> `gopls`)
 
 #### Setting to change the language server being used
 

src/goMain.ts

@@ -111,6 +111,12 @@ export function activate(ctx: vscode.ExtensionContext): void {
 			const languageServerExperimentalFeatures: any = vscode.workspace.getConfiguration('go').get('languageServerExperimentalFeatures') || {};
 			const langServerFlags: string[] = vscode.workspace.getConfiguration('go')['languageServerFlags'] || [];
 
+			// `-trace was a flag for `go-langserver` which is replaced with `-rpc.trace` for gopls to avoid crash
+			const traceFlagIndex = langServerFlags.indexOf('-trace');
+			if (traceFlagIndex > -1 && languageServerTool === 'gopls') {
+				langServerFlags[traceFlagIndex] = '-rpc.trace';
+			}
+
 			const c = new LanguageClient(
 				languageServerTool,
 				{