Keep payment violations domain-shaped (#55)

backend/src/main/java/fr/nessar/lmnporganizer/rental/adapter/in/web/common/RentalApiExceptionHandler.java

@@ -103,7 +103,8 @@ ResponseEntity<ValidationApiError> unreadableRequest() {
 }
 
 @ExceptionHandler(MethodArgumentTypeMismatchException.class)
-ResponseEntity<ValidationApiError> invalidParameter(MethodArgumentTypeMismatchException exception) {
+ResponseEntity<ValidationApiError> invalidParameter(
+	MethodArgumentTypeMismatchException exception) {
 	return validation(exception.getName(), "invalid");
 }
 

backend/src/main/java/fr/nessar/lmnporganizer/rental/adapter/in/web/rent/RentPaymentApi.java

@@ -14,6 +14,8 @@ import java.time.LocalDate;
 import java.util.List;
 
 final class RentPaymentApi {
+static final String CONCURRENT_CHANGE_CODE = "concurrent_change";
+
 private RentPaymentApi() {}
 
 record ConcurrentChangeResponse(String code, String message) {}

backend/src/main/java/fr/nessar/lmnporganizer/rental/adapter/in/web/rent/RentPaymentController.java

@@ -68,7 +68,7 @@ ResponseEntity<RentPaymentApi.ConcurrentChangeResponse> concurrentChange(
 	return ResponseEntity.status(HttpStatus.CONFLICT)
 		.body(
 			new RentPaymentApi.ConcurrentChangeResponse(
-				ConcurrentChange.CODE,
+				RentPaymentApi.CONCURRENT_CHANGE_CODE,
 				"La ressource a été modifiée ; rechargez-la puis réessayez."));
 }
 
@@ -78,8 +78,27 @@ ResponseEntity<RentPaymentApi.ValidationFailureResponse> invalidPayment(
 	return ResponseEntity.badRequest()
 		.body(
 			new RentPaymentApi.ValidationFailureResponse(
-				"validation_failed",
-				List.of(new RentPaymentApi.FieldErrorResponse(failure.field(), failure.code()))));
+				"validation_failed", List.of(validationError(failure.rule()))));
+}
+
+private static RentPaymentApi.FieldErrorResponse validationError(
+	RentPaymentValidationFailure.Rule rule) {
+	return switch (rule) {
+	case RECEIVED_AT_MUST_NOT_BE_FUTURE ->
+		new RentPaymentApi.FieldErrorResponse("receivedAt", "future_date");
+	case REFUNDED_AT_MUST_NOT_BE_FUTURE ->
+		new RentPaymentApi.FieldErrorResponse("refundedAt", "future_date");
+	case RENT_DUE_MUST_BELONG_TO_PAYMENT_LEASE ->
+		new RentPaymentApi.FieldErrorResponse("rentDueId", "different_lease");
+	case RENT_DUE_MUST_NOT_ALREADY_BE_ALLOCATED ->
+		new RentPaymentApi.FieldErrorResponse("rentDueId", "already_allocated");
+	case AMOUNT_MUST_NOT_EXCEED_PAYMENT_BALANCE ->
+		new RentPaymentApi.FieldErrorResponse("amount", "exceeds_payment_balance");
+	case AMOUNT_MUST_NOT_EXCEED_RENT_DUE_BALANCE ->
+		new RentPaymentApi.FieldErrorResponse("amount", "exceeds_rent_due_balance");
+	case AMOUNT_MUST_NOT_EXCEED_UNALLOCATED_BALANCE ->
+		new RentPaymentApi.FieldErrorResponse("amount", "exceeds_unallocated_balance");
+	};
 }
 
 @GetMapping

backend/src/main/java/fr/nessar/lmnporganizer/rental/application/rent/AllocateRentPaymentService.java

@@ -79,15 +79,13 @@ public RentPayment allocate(
 		}
 		if (!payment.leaseId().equals(due.leaseId())) {
 			throw new RentPaymentValidationFailure(
-				"rentDueId",
-				"different_lease",
+				RentPaymentValidationFailure.Rule.RENT_DUE_MUST_BELONG_TO_PAYMENT_LEASE,
 				"Une affectation doit viser une échéance du même bail.");
 		}
 		if (payment.allocations().stream()
 			.anyMatch(allocation -> allocation.rentDueId().equals(due.id()))) {
 			throw new RentPaymentValidationFailure(
-				"rentDueId",
-				"already_allocated",
+				RentPaymentValidationFailure.Rule.RENT_DUE_MUST_NOT_ALREADY_BE_ALLOCATED,
 				"Cette échéance a déjà reçu une affectation de ce règlement.");
 		}
 		if (due.settlement() == RentDueSettlement.PAID) {
@@ -96,14 +94,12 @@ public RentPayment allocate(
 		}
 		if (amount != null && amount.compareTo(payment.unallocatedBalance()) > 0) {
 			throw new RentPaymentValidationFailure(
-				"amount",
-				"exceeds_payment_balance",
+				RentPaymentValidationFailure.Rule.AMOUNT_MUST_NOT_EXCEED_PAYMENT_BALANCE,
 				"L'affectation dépasse le solde non affecté du règlement.");
 		}
 		if (amount != null && amount.compareTo(due.remainingAmount()) > 0) {
 			throw new RentPaymentValidationFailure(
-				"amount",
-				"exceeds_rent_due_balance",
+				RentPaymentValidationFailure.Rule.AMOUNT_MUST_NOT_EXCEED_RENT_DUE_BALANCE,
 				"L'affectation dépasse le solde restant de l'échéance.");
 		}
 		PaymentAllocation allocation =

backend/src/main/java/fr/nessar/lmnporganizer/rental/application/rent/RecordRentPaymentService.java

@@ -88,8 +88,7 @@ private RentPayment recordInTransaction(
 	LocalDate today = LocalDate.now(clock.withZone(timeZone));
 	if (receivedAt == null || receivedAt.isAfter(today)) {
 	throw new RentPaymentValidationFailure(
-		"receivedAt",
-		"future_date",
+		RentPaymentValidationFailure.Rule.RECEIVED_AT_MUST_NOT_BE_FUTURE,
 		"La date de réception du règlement ne peut pas être future.");
 	}
 	RentDue due =

backend/src/main/java/fr/nessar/lmnporganizer/rental/application/rent/RefundRentPaymentService.java

@@ -72,7 +72,8 @@ private RentPayment refundInTransaction(
 	LocalDate today = LocalDate.now(clock.withZone(timeZone));
 	if (refundedAt == null || refundedAt.isAfter(today)) {
 	throw new RentPaymentValidationFailure(
-		"refundedAt", "future_date", "La date du remboursement ne peut pas être future.");
+		RentPaymentValidationFailure.Rule.REFUNDED_AT_MUST_NOT_BE_FUTURE,
+		"La date du remboursement ne peut pas être future.");
 	}
 	RentPayment payment = payment(landlordId, paymentId);
 	if (payment.version() != paymentVersion) {
@@ -83,8 +84,7 @@ private RentPayment refundInTransaction(
 	}
 	if (amount != null && amount.compareTo(payment.unallocatedBalance()) > 0) {
 	throw new RentPaymentValidationFailure(
-		"amount",
-		"exceeds_unallocated_balance",
+		RentPaymentValidationFailure.Rule.AMOUNT_MUST_NOT_EXCEED_UNALLOCATED_BALANCE,
 		"Le remboursement dépasse le solde non affecté du règlement.");
 	}
 	RentPaymentRefund refund = RentPaymentRefund.recorded(refundId, payment, amount, refundedAt);

backend/src/main/java/fr/nessar/lmnporganizer/rental/application/rent/RentPaymentValidationFailure.java

@@ -3,20 +3,24 @@ package fr.nessar.lmnporganizer.rental.application.rent;
 import java.util.Objects;
 
 public final class RentPaymentValidationFailure extends RuntimeException {
-private final String field;
-private final String code;
+public enum Rule {
+	RECEIVED_AT_MUST_NOT_BE_FUTURE,
+	REFUNDED_AT_MUST_NOT_BE_FUTURE,
+	RENT_DUE_MUST_BELONG_TO_PAYMENT_LEASE,
+	RENT_DUE_MUST_NOT_ALREADY_BE_ALLOCATED,
+	AMOUNT_MUST_NOT_EXCEED_PAYMENT_BALANCE,
+	AMOUNT_MUST_NOT_EXCEED_RENT_DUE_BALANCE,
+	AMOUNT_MUST_NOT_EXCEED_UNALLOCATED_BALANCE
+}
 
-public RentPaymentValidationFailure(String field, String code, String message) {
+private final Rule rule;
+
+public RentPaymentValidationFailure(Rule rule, String message) {
 	super(message);
-	this.field = Objects.requireNonNull(field);
-	this.code = Objects.requireNonNull(code);
+	this.rule = Objects.requireNonNull(rule);
 }
 
-public String field() {
-	return field;
-}
-
-public String code() {
-	return code;
+public Rule rule() {
+	return rule;
 }
 }

backend/src/main/java/fr/nessar/lmnporganizer/rental/application/shared/ConcurrentChange.java

@@ -1,8 +1,6 @@
 package fr.nessar.lmnporganizer.rental.application.shared;
 
 public final class ConcurrentChange extends RuntimeException {
-public static final String CODE = "concurrent_change";
-
 public ConcurrentChange(String resource) {
 	super(resource + " changed concurrently; reload it and retry.");
 }

backend/src/test/java/fr/nessar/lmnporganizer/rental/adapter/in/web/RentalWebAdaptersTest.java

@@ -148,8 +148,7 @@ void authenticateLandlordAndFixTime() {
 		LeaseClauseCatalog.load(getClass().getResourceAsStream("/lease-clauses.yml"));
 	when(leaseClauseCatalog.available(anyString(), any()))
 		.thenAnswer(
-			invocation ->
-				clauses.available(invocation.getArgument(0), invocation.getArgument(1)));
+			invocation -> clauses.available(invocation.getArgument(0), invocation.getArgument(1)));
 }
 
 @Test
@@ -444,9 +443,7 @@ void leaseDraftRequestsRejectAnImpossibleAnnualRevisionDay() throws Exception {
 																"""))
 		.andExpect(status().isBadRequest())
 		.andExpect(jsonPath("$.code").value("validation_failed"))
-		.andExpect(
-			jsonPath("$.errors[0].field")
-				.value("legalTerms.rentRevision.annualRevisionDay"))
+		.andExpect(jsonPath("$.errors[0].field").value("legalTerms.rentRevision.annualRevisionDay"))
 		.andExpect(jsonPath("$.errors[0].code").value("invalid_date"));
 }
 

backend/src/test/java/fr/nessar/lmnporganizer/rental/adapter/in/web/common/RentPaymentConflictContractTest.java

@@ -3,6 +3,7 @@ package fr.nessar.lmnporganizer.rental.adapter.in.web.common;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import fr.nessar.lmnporganizer.rental.application.rent.RentPaymentConflict;
+import fr.nessar.lmnporganizer.rental.application.shared.ConcurrentChange;
 import org.junit.jupiter.api.Test;
 import org.springframework.http.HttpStatus;
 
@@ -16,4 +17,15 @@ void keepsBusinessConflictsAsUncoded409Responses() {
 	assertEquals(
 		new RentalApiExceptionHandler.ApiError("Échéance déjà réglée"), response.getBody());
 }
+
+@Test
+void keepsSharedConcurrencyFailuresAsSafeUncoded409Responses() {
+	var response = new RentalApiExceptionHandler().concurrent(new ConcurrentChange("Rent payment"));
+
+	assertEquals(HttpStatus.CONFLICT, response.getStatusCode());
+	assertEquals(
+		new RentalApiExceptionHandler.ApiError(
+			"La ressource a été modifiée ; rechargez-la puis réessayez."),
+		response.getBody());
+}
 }

backend/src/test/java/fr/nessar/lmnporganizer/rental/adapter/in/web/rent/RentPaymentControllerErrorTest.java

@@ -13,34 +13,41 @@ import fr.nessar.lmnporganizer.rental.application.rent.RentPaymentValidationFail
 import fr.nessar.lmnporganizer.rental.application.rent.ReverseRentPaymentService;
 import fr.nessar.lmnporganizer.rental.application.shared.ConcurrentChange;
 import java.util.List;
+import java.util.Map;
 import org.junit.jupiter.api.Test;
 import org.springframework.http.HttpStatus;
 
 class RentPaymentControllerErrorTest {
 @Test
-void mapsPaymentInputFailuresToTheStableValidationContract() {
-	RentPaymentController controller =
-		new RentPaymentController(
-			mock(RentPaymentHistoryService.class),
-			mock(RecordRentPaymentService.class),
-			mock(AllocateRentPaymentService.class),
-			mock(RefundRentPaymentService.class),
-			mock(ReverseRentPaymentService.class),
-			mock(GeneratePaymentReceiptService.class),
-			mock(AuthenticatedLandlord.class));
+void mapsPaymentRulesToTheStableValidationContract() {
+	Map<RentPaymentValidationFailure.Rule, RentPaymentApi.FieldErrorResponse> expected =
+		Map.of(
+			RentPaymentValidationFailure.Rule.RECEIVED_AT_MUST_NOT_BE_FUTURE,
+			new RentPaymentApi.FieldErrorResponse("receivedAt", "future_date"),
+			RentPaymentValidationFailure.Rule.REFUNDED_AT_MUST_NOT_BE_FUTURE,
+			new RentPaymentApi.FieldErrorResponse("refundedAt", "future_date"),
+			RentPaymentValidationFailure.Rule.RENT_DUE_MUST_BELONG_TO_PAYMENT_LEASE,
+			new RentPaymentApi.FieldErrorResponse("rentDueId", "different_lease"),
+			RentPaymentValidationFailure.Rule.RENT_DUE_MUST_NOT_ALREADY_BE_ALLOCATED,
+			new RentPaymentApi.FieldErrorResponse("rentDueId", "already_allocated"),
+			RentPaymentValidationFailure.Rule.AMOUNT_MUST_NOT_EXCEED_PAYMENT_BALANCE,
+			new RentPaymentApi.FieldErrorResponse("amount", "exceeds_payment_balance"),
+			RentPaymentValidationFailure.Rule.AMOUNT_MUST_NOT_EXCEED_RENT_DUE_BALANCE,
+			new RentPaymentApi.FieldErrorResponse("amount", "exceeds_rent_due_balance"),
+			RentPaymentValidationFailure.Rule.AMOUNT_MUST_NOT_EXCEED_UNALLOCATED_BALANCE,
+			new RentPaymentApi.FieldErrorResponse("amount", "exceeds_unallocated_balance"));
 
-	var response =
-		controller.invalidPayment(
-			new RentPaymentValidationFailure(
-				"amount", "exceeds_unallocated_balance", "Le remboursement dépasse le solde."));
+	expected.forEach(
+		(rule, error) -> {
+		var response =
+			controller()
+				.invalidPayment(new RentPaymentValidationFailure(rule, "internal detail"));
 
-	assertEquals(HttpStatus.BAD_REQUEST, response.getStatusCode());
-	assertEquals(
-		new RentPaymentApi.ValidationFailureResponse(
-			"validation_failed",
-			List.of(
-				new RentPaymentApi.FieldErrorResponse("amount", "exceeds_unallocated_balance"))),
-		response.getBody());
+		assertEquals(HttpStatus.BAD_REQUEST, response.getStatusCode());
+		assertEquals(
+			new RentPaymentApi.ValidationFailureResponse("validation_failed", List.of(error)),
+			response.getBody());
+		});
 }
 
 @Test
@@ -48,7 +55,7 @@ void mapsOnlyConcurrentChangesToTheCodedStaleContract() {
 	var response = controller().concurrentChange(new ConcurrentChange("Rent payment"));
 
 	assertEquals(HttpStatus.CONFLICT, response.getStatusCode());
-	assertEquals(ConcurrentChange.CODE, response.getBody().code());
+	assertEquals(RentPaymentApi.CONCURRENT_CHANGE_CODE, response.getBody().code());
 }
 
 private static RentPaymentController controller() {

backend/src/test/java/fr/nessar/lmnporganizer/rental/application/rent/AllocateRentPaymentServiceTest.java

@@ -271,8 +271,8 @@ void allocationMapsDuplicateAndBalanceFailuresToFields() {
 			() ->
 				service.allocate(
 					LANDLORD_ID, PAYMENT_ID, "operation-2", 4, DUE_ID, 2, new BigDecimal("10")));
-	assertEquals("rentDueId", duplicate.field());
-	assertEquals("already_allocated", duplicate.code());
+	assertEquals(
+		RentPaymentValidationFailure.Rule.RENT_DUE_MUST_NOT_ALREADY_BE_ALLOCATED, duplicate.rule());
 
 	RentPayment otherPayment =
 		RentPayment.reconstitute(
@@ -293,16 +293,17 @@ void allocationMapsDuplicateAndBalanceFailuresToFields() {
 			() ->
 				service.allocate(
 					LANDLORD_ID, PAYMENT_ID, "operation-3", 4, DUE_ID, 2, new BigDecimal("101")));
-	assertEquals("amount", balance.field());
-	assertEquals("exceeds_payment_balance", balance.code());
+	assertEquals(
+		RentPaymentValidationFailure.Rule.AMOUNT_MUST_NOT_EXCEED_PAYMENT_BALANCE, balance.rule());
 	RentPaymentValidationFailure dueBalance =
 		assertThrows(
 			RentPaymentValidationFailure.class,
 			() ->
 				service.allocate(
 					LANDLORD_ID, PAYMENT_ID, "operation-4", 4, DUE_ID, 2, new BigDecimal("41")));
-	assertEquals("amount", dueBalance.field());
-	assertEquals("exceeds_rent_due_balance", dueBalance.code());
+	assertEquals(
+		RentPaymentValidationFailure.Rule.AMOUNT_MUST_NOT_EXCEED_RENT_DUE_BALANCE,
+		dueBalance.rule());
 
 	verify(rentDues, never()).save(any());
 	verify(payments, never()).save(any());

backend/src/test/java/fr/nessar/lmnporganizer/rental/application/rent/RecordRentPaymentServiceTest.java

@@ -219,8 +219,8 @@ void staleOrPaidDueAndCashFromTheNextParisDayCreateNoPayment() {
 					LocalDate.of(2026, 2, 11),
 					PARIS,
 					new BigDecimal("1000")));
-	assertEquals("receivedAt", futureDate.field());
-	assertEquals("future_date", futureDate.code());
+	assertEquals(
+		RentPaymentValidationFailure.Rule.RECEIVED_AT_MUST_NOT_BE_FUTURE, futureDate.rule());
 	due.allocate(due.total());
 	assertThrows(
 		RentPaymentConflict.class,

backend/src/test/java/fr/nessar/lmnporganizer/rental/application/rent/RefundRentPaymentServiceTest.java

@@ -179,8 +179,8 @@ void futureDateAndStalePaymentVersionCreateNoRefund() {
 					new BigDecimal("50"),
 					LocalDate.of(2026, 2, 11),
 					PARIS));
-	assertEquals("refundedAt", futureDate.field());
-	assertEquals("future_date", futureDate.code());
+	assertEquals(
+		RentPaymentValidationFailure.Rule.REFUNDED_AT_MUST_NOT_BE_FUTURE, futureDate.rule());
 	assertThrows(
 		ConcurrentChange.class,
 		() ->
@@ -204,8 +204,9 @@ void futureDateAndStalePaymentVersionCreateNoRefund() {
 					new BigDecimal("1001"),
 					LocalDate.of(2026, 2, 9),
 					PARIS));
-	assertEquals("amount", excessAmount.field());
-	assertEquals("exceeds_unallocated_balance", excessAmount.code());
+	assertEquals(
+		RentPaymentValidationFailure.Rule.AMOUNT_MUST_NOT_EXCEED_UNALLOCATED_BALANCE,
+		excessAmount.rule());
 
 	verify(payments, never()).save(any());
 	verify(refunds, never()).save(any());