fix: handle subtasks in getTask method (#1254)

Co-authored-by: Ralph Khreish <Crunchyman-ralph@users.noreply.github.com>
Co-authored-by: claude[bot] <209825114+claude[bot]@users.noreply.github.com>

.changeset/fix-subtask-getTask.md

@@ -0,0 +1,7 @@
+---
+"task-master-ai": patch
+---
+
+Fixed issue where `tm show` command could not find subtasks using dotted notation IDs (e.g., '8.1'). 
+
+- The command now properly searches within parent task subtasks and returns the correct subtask information.

packages/tm-core/src/services/task-service.ts

@@ -135,15 +135,28 @@ export class TaskService {
 	}
 
 	/**
-	 * Get a single task by ID
+	 * Get a single task by ID - delegates to storage layer
 	 */
 	async getTask(taskId: string, tag?: string): Promise<Task | null> {
-		const result = await this.getTaskList({
+		// Use provided tag or get active tag
-			tag,
+		const activeTag = tag || this.getActiveTag();
-			includeSubtasks: true
-		});
 
-		return result.tasks.find((t) => t.id === taskId) || null;
+		try {
+			// Delegate to storage layer which handles the specific logic for tasks vs subtasks
+			return await this.storage.loadTask(String(taskId), activeTag);
+		} catch (error) {
+			throw new TaskMasterError(
+				`Failed to get task ${taskId}`,
+				ERROR_CODES.STORAGE_ERROR,
+				{
+					operation: 'getTask',
+					resource: 'task',
+					taskId: String(taskId),
+					tag: activeTag
+				},
+				error as Error
+			);
+		}
 	}
 
 	/**

packages/tm-core/src/storage/file-storage/file-storage.ts

@@ -105,9 +105,65 @@ export class FileStorage implements IStorage {
 
 	/**
 	 * Load a single task by ID from the tasks.json file
+	 * Handles both regular tasks and subtasks (with dotted notation like "1.2")
 	 */
 	async loadTask(taskId: string, tag?: string): Promise<Task | null> {
 		const tasks = await this.loadTasks(tag);
+
+		// Check if this is a subtask (contains a dot)
+		if (taskId.includes('.')) {
+			const [parentId, subtaskId] = taskId.split('.');
+			const parentTask = tasks.find((t) => String(t.id) === parentId);
+
+			if (!parentTask || !parentTask.subtasks) {
+				return null;
+			}
+
+			const subtask = parentTask.subtasks.find(
+				(st) => String(st.id) === subtaskId
+			);
+			if (!subtask) {
+				return null;
+			}
+
+			const toFullSubId = (maybeDotId: string | number): string => {
+				const depId = String(maybeDotId);
+				return depId.includes('.') ? depId : `${parentTask.id}.${depId}`;
+			};
+			const resolvedDependencies =
+				subtask.dependencies?.map((dep) => toFullSubId(dep)) ?? [];
+
+			// Return a Task-like object for the subtask with the full dotted ID
+			// Following the same pattern as findTaskById in utils.js
+			const subtaskResult = {
+				...subtask,
+				id: taskId, // Use the full dotted ID
+				title: subtask.title || `Subtask ${subtaskId}`,
+				description: subtask.description || '',
+				status: subtask.status || 'pending',
+				priority: subtask.priority || parentTask.priority || 'medium',
+				dependencies: resolvedDependencies,
+				details: subtask.details || '',
+				testStrategy: subtask.testStrategy || '',
+				subtasks: [],
+				tags: parentTask.tags || [],
+				assignee: subtask.assignee || parentTask.assignee,
+				complexity: subtask.complexity || parentTask.complexity,
+				createdAt: subtask.createdAt || parentTask.createdAt,
+				updatedAt: subtask.updatedAt || parentTask.updatedAt,
+				// Add reference to parent task for context (like utils.js does)
+				parentTask: {
+					id: parentTask.id,
+					title: parentTask.title,
+					status: parentTask.status
+				},
+				isSubtask: true
+			};
+
+			return subtaskResult;
+		}
+
+		// Handle regular task lookup
 		return tasks.find((task) => String(task.id) === String(taskId)) || null;
 	}