fix(audience): take the sample cap and truncation bound from the engine

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: thomasguillot

plugins/newspack-plugin/src/wizards/audience/views/pricing-rules/catalog-impact.test.jsx

@@ -235,6 +235,30 @@ describe( 'CatalogImpact', () => {
 		} );
 	} );
 
+	// The engine echoes the cap it applied; the client's constant is only a fallback.
+	it( 'says the table is a sample against the cap the engine reports', async () => {
+		apiFetch.mockResolvedValue( detail( { preview_limited: true, sample_count: 3, sample_limit: 3 } ) );
+		render( <CatalogImpact stats={ stats() } /> );
+
+		await act( async () => {
+			openModal();
+		} );
+
+		expect( screen.getByText( 'Showing a sample of 3 products.' ) ).toBeInTheDocument();
+	} );
+
+	// The engine flags a preview as limited when it merely skipped an unpriceable product.
+	it( 'says nothing about sampling when the table never reached the cap', async () => {
+		apiFetch.mockResolvedValue( detail( { preview_limited: true, sample_count: 3, sample_limit: 50 } ) );
+		render( <CatalogImpact stats={ stats() } /> );
+
+		await act( async () => {
+			openModal();
+		} );
+
+		expect( screen.queryByText( /Showing a sample of/ ) ).not.toBeInTheDocument();
+	} );
+
 	it( 'withholds the table button and explains itself when nothing is affected', () => {
 		render( <CatalogImpact stats={ stats( { total_matching: 0 } ) } /> );
 

plugins/newspack-plugin/src/wizards/audience/views/pricing-rules/catalog-impact.tsx

@@ -44,7 +44,7 @@ export default function CatalogImpact( { stats }: CatalogImpactProps ) {
 	const open = useCallback( () => {
 		setIsOpen( true );
 		setHasError( false );
-		// A landed sample is kept; a failure is retried.
+		// A failure is retried; only a landed sample short-circuits.
 		if ( detail || inFlight.current ) {
 			return;
 		}
@@ -77,6 +77,7 @@ export default function CatalogImpact( { stats }: CatalogImpactProps ) {
 			emptyReason = 'no-products';
 		}
 	}
+	const note = detail ? sampleNote( detail ) : null;
 
 	return (
 		<Card.Root className="newspack-pricing-rules__impact">
@@ -108,9 +109,7 @@ export default function CatalogImpact( { stats }: CatalogImpactProps ) {
 						{ ! hasError && emptyReason && <ImpactEmpty reason={ emptyReason } /> }
 						{ ! hasError && detail && ! emptyReason && (
 							<>
-								{ detail.preview_limited && detail.sample_count >= IMPACT_SAMPLE_LIMIT && (
-									<p className="newspack-pricing-rules__muted">{ sampleNote( detail.sample_count ) }</p>
-								) }
+								{ note && <p className="newspack-pricing-rules__muted">{ note }</p> }
 								<ImpactTable
 									baseline={ detail.sample }
 									segmentGroups={ detail.segment_groups ?? [] }

plugins/newspack-plugin/src/wizards/audience/views/pricing-rules/constants.ts

@@ -9,7 +9,7 @@ export const RULE_PREVIEW_API_PATH = '/wc-dynamic-pricing/v1/rules/preview';
 export const IMPACT_PREVIEW_API_PATH = '/wc-dynamic-pricing/v1/impact-preview';
 
 /**
- * The engine's route maximum. Compared against sample_count because the engine
- * flags a preview limited even when it merely skipped a product it could not price.
+ * The engine's route maximum, which the catalog read asks for in full. Also the
+ * fallback when a payload omits the cap it applied.
  */
 export const IMPACT_SAMPLE_LIMIT = 50;

plugins/newspack-plugin/src/wizards/audience/views/pricing-rules/impact-format.ts

@@ -13,10 +13,10 @@ import { __, _n, sprintf } from '@wordpress/i18n';
  * Internal dependencies
  */
 import { formatCount } from '../../../../../packages/components/src/breadcrumbs/format-count';
+import { IMPACT_SAMPLE_LIMIT } from './constants';
 
 // Re-exported, not reimplemented: only this helper normalises the locales
-// WordPress ships that Intl rejects, and the header count beside these figures
-// already uses it.
+// WordPress ships that Intl rejects.
 export { formatCount };
 
 export function formatPrice( amount: number, currency: PricingRulesCurrency ): string {
@@ -45,12 +45,18 @@ export function cycleMarkerNote(): string {
 }
 
 /**
- * Shared so the modal and the editor preview cannot drift into two msgids.
+ * The caption for a table the engine capped, or null when it did not. The cap comes
+ * from the payload because the engine's two entry points default differently, and
+ * `preview_limited` alone cannot tell a capped sample from one that skipped a
+ * product it could not price.
  */
-export function sampleNote( sampleCount: number ): string {
+export function sampleNote( payload: CatalogImpactResponse ): string | null {
+	if ( ! payload.preview_limited || payload.sample_count < ( payload.sample_limit ?? IMPACT_SAMPLE_LIMIT ) ) {
+		return null;
+	}
 	return sprintf(
 		/* translators: %s: how many products the table lists. */
-		_n( 'Showing a sample of %s product.', 'Showing a sample of %s products.', sampleCount, 'newspack-plugin' ),
-		formatCount( sampleCount )
+		_n( 'Showing a sample of %s product.', 'Showing a sample of %s products.', payload.sample_count, 'newspack-plugin' ),
+		formatCount( payload.sample_count )
 	);
 }

plugins/newspack-plugin/src/wizards/audience/views/pricing-rules/impact-stats.test.jsx

@@ -66,12 +66,18 @@ describe( 'ImpactStats', () => {
 		expect( screen.getByText( /new sign-ups only/ ) ).toBeInTheDocument();
 	} );
 
-	it( 'marks a capped count as a lower bound, and only that count', () => {
+	it( 'leaves the product count exact when only the audience is capped', () => {
 		render( <ImpactStats totalMatching={ 500 } countLimited={ false } audience={ audience( { count_limited: true } ) } /> );
 		expect( screen.getByText( '500' ) ).toBeInTheDocument();
 		expect( screen.getByText( '12+' ) ).toBeInTheDocument();
 	} );
 
+	it( 'bounds the renewal split when the audience is capped', () => {
+		render( <ImpactStats totalMatching={ 500 } countLimited={ false } audience={ audience( { count_limited: true } ) } /> );
+		expect( screen.getByText( '8+' ) ).toBeInTheDocument();
+		expect( screen.getByText( '4+ protected' ) ).toBeInTheDocument();
+	} );
+
 	it( 'marks both counts as lower bounds when both are capped', () => {
 		render( <ImpactStats totalMatching={ 500 } countLimited audience={ audience( { count_limited: true } ) } /> );
 		expect( screen.getByText( '500+' ) ).toBeInTheDocument();

plugins/newspack-plugin/src/wizards/audience/views/pricing-rules/impact-stats.tsx

@@ -51,13 +51,15 @@ export default function ImpactStats( { totalMatching, countLimited, audience }:
 				<Stat value={ bounded( totalMatching, countLimited ) } label={ __( 'Products affected', 'newspack-plugin' ) } />
 				{ scope && <Stat value={ bounded( scope.total, scope.count_limited ) } label={ __( 'Subscribers in scope', 'newspack-plugin' ) } /> }
 				{ scope && ! isLocked && (
+					// The engine truncates oldest-first and the oldest are the ones a cohort
+					// gate protects, so a capped split under-reports who is repriced.
 					<Stat
-						value={ formatCount( scope.caught ) }
+						value={ bounded( scope.caught, scope.count_limited ) }
 						label={ __( 'Eligible at renewal', 'newspack-plugin' ) }
 						note={ sprintf(
 							/* translators: %s: how many subscribers in scope keep their current price. */
 							_n( '%s protected', '%s protected', scope.protected, 'newspack-plugin' ),
-							formatCount( scope.protected )
+							bounded( scope.protected, scope.count_limited )
 						) }
 					/>
 				) }

plugins/newspack-plugin/src/wizards/audience/views/pricing-rules/list.tsx

@@ -127,10 +127,8 @@ export default function PricingRulesList() {
 		fetchData();
 	}, [ fetchData ] );
 
-	// One row is enough: total_matching and count_limited do not vary with the
-	// limit, and pricing the whole sample costs several times as much. `audience`
-	// renders from this payload too, so it must stay limit-invariant when the
-	// engine starts sending it.
+	// One row is enough: total_matching, count_limited and audience are all computed
+	// before the limit applies, and pricing the whole sample costs several times as much.
 	const statsRequest = useRef( 0 );
 	const gateTimer = useRef< ReturnType< typeof setTimeout > | undefined >( undefined );
 

plugins/newspack-plugin/src/wizards/audience/views/pricing-rules/rule-preview.test.jsx

@@ -140,6 +140,14 @@ describe( 'RulePreview', () => {
 		expect( screen.queryByText( /Showing a sample of/ ) ).not.toBeInTheDocument();
 	} );
 
+	// The per-rule route takes no limit at all, so only the payload knows the cap.
+	it( 'measures the sample against the cap the engine reports', async () => {
+		apiFetch.mockResolvedValue( response( { preview_limited: true, sample_count: 10, sample_limit: 10, total_matching: 120 } ) );
+		render( <RulePreview body={ {} } /> );
+		await settle();
+		expect( screen.getByText( 'Showing a sample of 10 products.' ) ).toBeInTheDocument();
+	} );
+
 	// The engine flags a preview as limited when it merely skipped an unpriceable product.
 	it( 'says nothing about sampling when the table never reached the cap', async () => {
 		apiFetch.mockResolvedValue( response( { preview_limited: true, sample_count: 33, total_matching: 36 } ) );

plugins/newspack-plugin/src/wizards/audience/views/pricing-rules/rule-preview.tsx

@@ -22,7 +22,7 @@ import ImpactEmpty, { type ImpactEmptyReason } from './impact-empty';
 import ImpactStats from './impact-stats';
 import ImpactTable from './impact-table';
 import { sampleNote } from './impact-format';
-import { RULE_PREVIEW_API_PATH as PREVIEW_PATH, IMPACT_SAMPLE_LIMIT } from './constants';
+import { RULE_PREVIEW_API_PATH as PREVIEW_PATH } from './constants';
 
 const DEBOUNCE_MS = 500;
 
@@ -95,6 +95,7 @@ export default function RulePreview( { body, showCycleNote }: RulePreviewProps )
 	}
 
 	const preview = data as RulePreviewResponse;
+	const note = sampleNote( preview );
 
 	return (
 		<div className={ `newspack-pricing-rules__preview${ isLoading ? ' is-loading' : '' }` }>
@@ -105,9 +106,7 @@ export default function RulePreview( { body, showCycleNote }: RulePreviewProps )
 				currency={ preview.currency }
 				showCycleNote={ showCycleNote }
 			/>
-			{ preview.preview_limited && preview.sample_count >= IMPACT_SAMPLE_LIMIT && (
-				<p className="newspack-pricing-rules__muted">{ sampleNote( preview.sample_count ) }</p>
-			) }
+			{ note && <p className="newspack-pricing-rules__muted">{ note }</p> }
 		</div>
 	);
 }

plugins/newspack-plugin/src/wizards/audience/views/pricing-rules/types.d.ts

@@ -126,10 +126,12 @@ interface CatalogImpactResponse {
 	count_limited: boolean;
 	preview_limited: boolean;
 	sample_count: number;
+	// The cap the engine applied; omitted rather than guessed when it had none.
+	sample_limit?: number;
 	currency: PricingRulesCurrency;
 	sample: CatalogImpactRow[];
 	segment_groups?: SegmentImpactGroup[];
-	// Absent on the catalogue route until the engine's subscriptions layer sends it.
+	// Absent unless the engine's subscriptions layer is present.
 	audience?: RuleAudienceData;
 }