fix(expand-all): resolve NaN errors and improve error reporting

- Fix expand-all command bugs that caused NaN errors with --all option and JSON formatting errors with research enabled

- Improve error handling to provide clear feedback when subtask generation fails

- Include task IDs and actionable suggestions in error messages

.changeset/all-parks-sort.md

@@ -0,0 +1,5 @@
+---
+'task-master-ai': patch
+---
+
+- Fix expand-all command bugs that caused NaN errors with --all option and JSON formatting errors with research enabled. Improved error handling to provide clear feedback when subtask generation fails, including task IDs and actionable suggestions.

scripts/modules/ai-services.js

@@ -897,8 +897,12 @@ function parseSubtasksFromText(text, startId, expectedCount, parentTaskId) {
 			throw new Error('Parsed content is not an array');
 		}
 
+		// Set default values for optional parameters
+		startId = startId || 1;
+		expectedCount = expectedCount || subtasks.length;
+
 		// Log warning if count doesn't match expected
-		if (subtasks.length !== expectedCount) {
+		if (expectedCount && subtasks.length !== expectedCount) {
 			log(
 				'warn',
 				`Expected ${expectedCount} subtasks, but parsed ${subtasks.length}`
@@ -908,10 +912,10 @@ function parseSubtasksFromText(text, startId, expectedCount, parentTaskId) {
 		// Normalize subtask IDs if they don't match
 		subtasks = subtasks.map((subtask, index) => {
 			// Assign the correct ID if it doesn't match
-			if (subtask.id !== startId + index) {
+			if (!subtask.id || subtask.id !== startId + index) {
 				log(
 					'warn',
-					`Correcting subtask ID from ${subtask.id} to ${startId + index}`
+					`Correcting subtask ID from ${subtask.id || 'undefined'} to ${startId + index}`
 				);
 				subtask.id = startId + index;
 			}
@@ -928,8 +932,10 @@ function parseSubtasksFromText(text, startId, expectedCount, parentTaskId) {
 			// Ensure status is 'pending'
 			subtask.status = 'pending';
 
-			// Add parentTaskId
-			subtask.parentTaskId = parentTaskId;
+			// Add parentTaskId if provided
+			if (parentTaskId) {
+				subtask.parentTaskId = parentTaskId;
+			}
 
 			return subtask;
 		});
@@ -937,26 +943,8 @@ function parseSubtasksFromText(text, startId, expectedCount, parentTaskId) {
 		return subtasks;
 	} catch (error) {
 		log('error', `Error parsing subtasks: ${error.message}`);
-
-		// Create a fallback array of empty subtasks if parsing fails
-		log('warn', 'Creating fallback subtasks');
-
-		const fallbackSubtasks = [];
-
-		for (let i = 0; i < expectedCount; i++) {
-			fallbackSubtasks.push({
-				id: startId + i,
-				title: `Subtask ${startId + i}`,
-				description: 'Auto-generated fallback subtask',
-				dependencies: [],
-				details:
-					'This is a fallback subtask created because parsing failed. Please update with real details.',
-				status: 'pending',
-				parentTaskId: parentTaskId
-			});
-		}
-
-		return fallbackSubtasks;
+		// Re-throw the error to be handled by the caller
+		throw error;
 	}
 }
 

scripts/modules/task-manager.js

@@ -2711,6 +2711,9 @@ async function expandAllTasks(
 	}
 
 	report(`Expanding all pending tasks with ${numSubtasks} subtasks each...`);
+	if (useResearch) {
+		report('Using research-backed AI for more detailed subtasks');
+	}
 
 	// Load tasks
 	let data;
@@ -2772,6 +2775,7 @@ async function expandAllTasks(
 	}
 
 	let expandedCount = 0;
+	let expansionErrors = 0;
 	try {
 		// Sort tasks by complexity if report exists, otherwise by ID
 		if (complexityReport && complexityReport.complexityAnalysis) {
@@ -2852,12 +2856,12 @@ async function expandAllTasks(
 					mcpLog
 				);
 
-				if (aiResponse && aiResponse.subtasks) {
+				if (aiResponse && aiResponse.subtasks && Array.isArray(aiResponse.subtasks) && aiResponse.subtasks.length > 0) {
 					// Process and add the subtasks to the task
 					task.subtasks = aiResponse.subtasks.map((subtask, index) => ({
 						id: index + 1,
-						title: subtask.title,
-						description: subtask.description,
+						title: subtask.title || `Subtask ${index + 1}`,
+						description: subtask.description || 'No description provided',
 						status: 'pending',
 						dependencies: subtask.dependencies || [],
 						details: subtask.details || ''
@@ -2865,11 +2869,24 @@ async function expandAllTasks(
 
 					report(`Added ${task.subtasks.length} subtasks to task ${task.id}`);
 					expandedCount++;
+				} else if (aiResponse && aiResponse.error) {
+					// Handle error response
+					const errorMsg = `Failed to generate subtasks for task ${task.id}: ${aiResponse.error}`;
+					report(errorMsg, 'error');
+					
+					// Add task ID to error info and provide actionable guidance
+					const suggestion = aiResponse.suggestion.replace('<id>', task.id);
+					report(`Suggestion: ${suggestion}`, 'info');
+					
+					expansionErrors++;
 				} else {
 					report(`Failed to generate subtasks for task ${task.id}`, 'error');
+					report(`Suggestion: Run 'task-master update-task --id=${task.id} --prompt="Generate subtasks for this task"' to manually create subtasks.`, 'info');
+					expansionErrors++;
 				}
 			} catch (error) {
 				report(`Error expanding task ${task.id}: ${error.message}`, 'error');
+				expansionErrors++;
 			}
 
 			// Small delay to prevent rate limiting
@@ -2891,7 +2908,8 @@ async function expandAllTasks(
 			success: true,
 			expandedCount,
 			tasksToExpand: tasksToExpand.length,
-			message: `Successfully expanded ${expandedCount} out of ${tasksToExpand.length} tasks`
+			expansionErrors,
+			message: `Successfully expanded ${expandedCount} out of ${tasksToExpand.length} tasks${expansionErrors > 0 ? ` (${expansionErrors} errors)` : ''}`
 		};
 	} catch (error) {
 		report(`Error expanding tasks: ${error.message}`, 'error');
@@ -5609,6 +5627,8 @@ async function getSubtasksFromAI(
 			mcpLog.info('Calling AI to generate subtasks');
 		}
 
+		let responseText;
+		
 		// Call the AI - with research if requested
 		if (useResearch && perplexity) {
 			if (mcpLog) {
@@ -5633,8 +5653,7 @@ async function getSubtasksFromAI(
 				max_tokens: session?.env?.MAX_TOKENS || CONFIG.maxTokens
 			});
 
-			const responseText = result.choices[0].message.content;
-			return parseSubtasksFromText(responseText);
+			responseText = result.choices[0].message.content;
 		} else {
 			// Use regular Claude
 			if (mcpLog) {
@@ -5642,14 +5661,39 @@ async function getSubtasksFromAI(
 			}
 
 			// Call the streaming API
-			const responseText = await _handleAnthropicStream(
+			responseText = await _handleAnthropicStream(
 				client,
 				apiParams,
 				{ mcpLog, silentMode: isSilentMode() },
 				!isSilentMode()
 			);
+		}
 
-			return parseSubtasksFromText(responseText);
+		// Ensure we have a valid response
+		if (!responseText) {
+			throw new Error('Empty response from AI');
+		}
+
+		// Try to parse the subtasks
+		try {
+			const parsedSubtasks = parseSubtasksFromText(responseText);
+			if (!parsedSubtasks || !Array.isArray(parsedSubtasks) || parsedSubtasks.length === 0) {
+				throw new Error('Failed to parse valid subtasks array from AI response');
+			}
+			return { subtasks: parsedSubtasks };
+		} catch (parseError) {
+			if (mcpLog) {
+				mcpLog.error(`Error parsing subtasks: ${parseError.message}`);
+				mcpLog.error(`Response start: ${responseText.substring(0, 200)}...`);
+			} else {
+				log('error', `Error parsing subtasks: ${parseError.message}`);
+			}
+			// Return error information instead of fallback subtasks
+			return { 
+				error: parseError.message,
+				taskId: null, // This will be filled in by the calling function
+				suggestion: "Use 'task-master update-task --id=<id> --prompt=\"Generate subtasks for this task\"' to manually create subtasks."
+			};
 		}
 	} catch (error) {
 		if (mcpLog) {
@@ -5657,7 +5701,12 @@ async function getSubtasksFromAI(
 		} else {
 			log('error', `Error generating subtasks: ${error.message}`);
 		}
-		throw error;
+		// Return error information instead of fallback subtasks
+		return { 
+			error: error.message,
+			taskId: null, // This will be filled in by the calling function 
+			suggestion: "Use 'task-master update-task --id=<id> --prompt=\"Generate subtasks for this task\"' to manually create subtasks."
+		};
 	}
 }