feat(recipes): return fail(422) when all ingredients filter to empty

Prevents a silent 400 from the backend when the user submits a form
where every ingredient row has quantity <= 0 or blank name.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/routes/(app)/recipes/[id]/edit/+page.server.ts

@@ -67,6 +67,13 @@ export const actions: Actions = {
 			return fail(400, { error: 'Ungültige Formulardaten' });
 		}
 
+		const filteredIngredients = (
+			parsedIngredients as { name: string; quantity: string; unit: string }[]
+		).filter((ing) => ing.name?.trim() && Number(ing.quantity) > 0);
+
+		if (!filteredIngredients.length)
+			return fail(422, { error: 'Mindestens eine gültige Zutat ist erforderlich' });
+
 		const api = apiClient(fetch);
 		const { error: apiError } = await api.PUT('/v1/recipes/{id}', {
 			params: { path: { id: params.id } },
@@ -76,14 +83,12 @@ export const actions: Actions = {
 				cookTimeMin: cookTimeMin ? Number(cookTimeMin) || null : null,
 				effort,
 				heroImageUrl,
-				ingredients: (parsedIngredients as { name: string; quantity: string; unit: string }[])
+				ingredients: filteredIngredients.map((ing, i) => ({
-					.filter((ing) => ing.name?.trim() && Number(ing.quantity) > 0)
+					newIngredientName: ing.name.trim(),
-					.map((ing, i) => ({
+					quantity: Number(ing.quantity),
-						newIngredientName: ing.name.trim(),
+					unit: ing.unit || '',
-						quantity: Number(ing.quantity),
+					sortOrder: i
-						unit: ing.unit || '',
+				})),
-						sortOrder: i
-					})),
 				steps: (parsedSteps as string[])
 					.filter((s) => s?.trim())
 					.map((s, i) => ({ stepNumber: i + 1, instruction: s.trim() })),

frontend/src/routes/(app)/recipes/[id]/edit/page.server.test.ts

@@ -84,7 +84,7 @@ describe('edit recipe page — update action', () => {
 			name: 'Test Rezept',
 			effort: 'easy',
 			tagIds: ['t1'],
-			ingredientsJson: '[]',
+			ingredientsJson: JSON.stringify([{ name: 'Spaghetti', quantity: 200, unit: 'g' }]),
 			stepsJson: '[]',
 			...overrides
 		};
@@ -236,6 +236,24 @@ describe('edit recipe page — update action', () => {
 		expect(body.ingredients[0].newIngredientName).toBe('Spaghetti');
 	});
 
+	it('returns fail(422) when all ingredients filter to empty after quantity check', async () => {
+		const result = await actions.update({
+			request: {
+				formData: async () =>
+					makeFormData({
+						ingredientsJson: JSON.stringify([
+							{ name: 'Salt', quantity: 0, unit: 'tsp' },
+							{ name: '', quantity: 100, unit: 'g' }
+						])
+					})
+			},
+			fetch: vi.fn(),
+			params: { id: 'r1' }
+		} as any);
+		expect(result.status).toBe(422);
+		expect(result.data.error).toMatch(/zutat/i);
+	});
+
 	it('returns fail(500) when API returns error', async () => {
 		mockPut.mockResolvedValue({ error: { status: 500 } });
 		const result = await actions.update({

frontend/src/routes/(app)/recipes/new/+page.server.ts

@@ -40,6 +40,13 @@ export const actions: Actions = {
 			return fail(400, { error: 'Ungültige Formulardaten' });
 		}
 
+		const filteredIngredients = (
+			parsedIngredients as { name: string; quantity: string; unit: string }[]
+		).filter((ing) => ing.name?.trim() && Number(ing.quantity) > 0);
+
+		if (!filteredIngredients.length)
+			return fail(422, { error: 'Mindestens eine gültige Zutat ist erforderlich' });
+
 		const api = apiClient(fetch);
 		const { error: apiError } = await api.POST('/v1/recipes', {
 			body: {
@@ -48,14 +55,12 @@ export const actions: Actions = {
 				cookTimeMin: cookTimeMin ? Number(cookTimeMin) || null : null,
 				effort,
 				heroImageUrl,
-				ingredients: (parsedIngredients as { name: string; quantity: string; unit: string }[])
+				ingredients: filteredIngredients.map((ing, i) => ({
-					.filter((ing) => ing.name?.trim() && Number(ing.quantity) > 0)
+					newIngredientName: ing.name.trim(),
-					.map((ing, i) => ({
+					quantity: Number(ing.quantity),
-						newIngredientName: ing.name.trim(),
+					unit: ing.unit || '',
-						quantity: Number(ing.quantity),
+					sortOrder: i
-						unit: ing.unit || '',
+				})),
-						sortOrder: i
-					})),
 				steps: (parsedSteps as string[])
 					.filter((s) => s?.trim())
 					.map((s, i) => ({ stepNumber: i + 1, instruction: s.trim() })),

frontend/src/routes/(app)/recipes/new/page.server.test.ts

@@ -62,7 +62,7 @@ describe('new recipe page — create action', () => {
 			name: 'Test Rezept',
 			effort: 'easy',
 			tagIds: ['t1'],
-			ingredientsJson: '[]',
+			ingredientsJson: JSON.stringify([{ name: 'Spaghetti', quantity: 200, unit: 'g' }]),
 			stepsJson: '[]',
 			...overrides
 		};
@@ -189,6 +189,23 @@ describe('new recipe page — create action', () => {
 		expect(body.ingredients[0].newIngredientName).toBe('Spaghetti');
 	});
 
+	it('returns fail(422) when all ingredients filter to empty after quantity check', async () => {
+		const result = await actions.create({
+			request: {
+				formData: async () =>
+					makeFormData({
+						ingredientsJson: JSON.stringify([
+							{ name: 'Salt', quantity: 0, unit: 'tsp' },
+							{ name: '', quantity: 100, unit: 'g' }
+						])
+					})
+			},
+			fetch: vi.fn()
+		} as any);
+		expect(result.status).toBe(422);
+		expect(result.data.error).toMatch(/zutat/i);
+	});
+
 	it('returns fail(500) when API returns error', async () => {
 		mockPost.mockResolvedValue({ error: { status: 500 } });
 		const result = await actions.create({