Do not start LS if core for board is missing.

- Added a 20 sec timeout to the LS process start.
 - Discard running LS FQBN when the LS start has failed.

Signed-off-by: Akos Kitta <kittaakos@typefox.io>

arduino-ide-extension/src/browser/arduino-frontend-contribution.tsx

@@ -229,11 +229,17 @@ export class ArduinoFrontendContribution implements FrontendApplicationContribut
     protected async startLanguageServer(fqbn: string, name: string | undefined): Promise<void> {
         const release = await this.languageServerStartMutex.acquire();
         try {
+            await this.hostedPluginSupport.didStart;
+            const details = await this.boardsService.getBoardDetails({ fqbn });
+            if (!details) {
+                // Core is not installed for the selected board.
+                console.info(`Could not start language server for ${fqbn}. The core is not installed for the board.`);
+                return;
+            }
             if (fqbn === this.languageServerFqbn) {
                 // NOOP
                 return;
             }
-            await this.hostedPluginSupport.didStart;
             this.logger.info(`Starting language server: ${fqbn}`);
             const log = this.arduinoPreferences.get('arduino.language.log');
             let currentSketchPath: string | undefined = undefined;
@@ -249,7 +255,9 @@ export class ArduinoFrontendContribution implements FrontendApplicationContribut
                 this.fileSystem.fsPath(new URI(cliUri)),
                 this.fileSystem.fsPath(new URI(lsUri)),
             ]);
-            this.languageServerFqbn = await this.commandRegistry.executeCommand('arduino.languageserver.start', {
+            this.languageServerFqbn = await Promise.race([
+                new Promise<undefined>((_, reject) => setTimeout(() => reject(new Error(`Timeout after ${20_000} ms.`)), 20_000)),
+                this.commandRegistry.executeCommand<string>('arduino.languageserver.start', {
                     lsPath,
                     cliPath,
                     clangdPath,
@@ -258,7 +266,11 @@ export class ArduinoFrontendContribution implements FrontendApplicationContribut
                         fqbn,
                         name: name ? `"${name}"` : undefined
                     }
-            });
+                })
+            ]);
+        } catch (e) {
+            console.log(`Failed to start language server for ${fqbn}`, e);
+            this.languageServerFqbn = undefined;
         } finally {
             release();
         }