Fixes #25516: Generated task.json from grunt file has warnings

src/vs/workbench/parts/tasks/electron-browser/task.contribution.ts

@@ -138,9 +138,14 @@ abstract class OpenTaskConfigurationAction extends Action {
 							value.stderr.forEach((line) => {
 								outputChannel.append(line + '\n');
 							});
+							if (config && (!config.tasks || config.tasks.length === 0)) {
 								this.messageService.show(Severity.Warning, nls.localize('ConfigureTaskRunnerAction.autoDetect', 'Auto detecting the task system failed. Using default template. Consult the task output for details.'));
 								return selection.content;
-						} else if (config) {
+							} else {
+								this.messageService.show(Severity.Warning, nls.localize('ConfigureTaskRunnerAction.autoDetectError', 'Auto detecting the task system produced errors. Consult the task output for details.'));
+							}
+						}
+						if (config) {
 							if (value.stdout && value.stdout.length > 0) {
 								value.stdout.forEach(line => outputChannel.append(line + '\n'));
 							}

src/vs/workbench/parts/tasks/node/processRunnerDetector.ts

@@ -320,9 +320,7 @@ export class ProcessRunnerDetector {
 			tasks.forEach((task) => {
 				taskConfigs.push({
 					taskName: task,
-					identifier: task,
-					args: [],
-					isWatching: false
+					args: []
 				});
 			});
 		} else {
@@ -339,10 +337,8 @@ export class ProcessRunnerDetector {
 				this._stdout.push(nls.localize('TaskSystemDetector.buildTaskDetected', 'Build task named \'{0}\' detected.', name));
 				taskConfigs.push({
 					taskName: name,
-					identifier: name,
 					args: [],
 					isBuildCommand: true,
-					isWatching: false,
 					problemMatcher: problemMatchers
 				});
 			}
@@ -351,7 +347,6 @@ export class ProcessRunnerDetector {
 				this._stdout.push(nls.localize('TaskSystemDetector.testTaskDetected', 'Test task named \'{0}\' detected.', name));
 				taskConfigs.push({
 					taskName: name,
-					identifier: name,
 					args: [],
 					isTestCommand: true
 				});