test(document): prove the DB rejects end-before-start; assert persisted end (#678)

Addresses Sara's review concerns:
- Add a negative Testcontainers test: saveAndFlush of a RANGE with end < start
  throws DataIntegrityViolationException, proving chk_meta_date_end_after_start
  actually fires (H2 wouldn't) and exercising the backstop's trigger end-to-end.
  Guards against silent app/DB drift if the service guard ever regresses.
- Tighten updateDocument_acceptsRange_whenEndAfterStart to assert the persisted
  end value, not just that save was called.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/src/main/java/org/raddatz/familienarchiv/document/DocumentService.java

@@ -381,6 +381,7 @@ public class DocumentService {
         doc.setTitle(dto.getTitle());
         doc.setDocumentDate(dto.getDocumentDate());
         applyDatePrecision(doc, dto);
+        validateDateRange(doc); // guard before any save (updateDocumentTags below persists)
         doc.setLocation(dto.getLocation());
         doc.setTranscription(dto.getTranscription());
         doc.setSummary(dto.getSummary());
@@ -468,6 +469,31 @@ public class DocumentService {
         }
     }
 
+    /**
+     * Friendly guard for the two V69 date-range CHECK constraints, run before save so a
+     * user date typo returns a clean 400 INVALID_DATE_RANGE instead of falling through to
+     * the generic handler (HTTP 500 + Sentry + ERROR log). Validates the post-apply {@code doc}
+     * state, not the DTO, because precision/end may have been carried over from the stored row
+     * when the DTO field was null. The DB CHECK remains the backstop; this never weakens it.
+     */
+    private void validateDateRange(Document doc) {
+        // Mirrors chk_meta_date_end_after_start: end >= start, with null start allowed.
+        // Use isBefore (equal dates are valid) — never !isAfter, which would contradict the DB's >=.
+        if (doc.getMetaDatePrecision() == DatePrecision.RANGE
+                && doc.getDocumentDate() != null
+                && doc.getMetaDateEnd() != null
+                && doc.getMetaDateEnd().isBefore(doc.getDocumentDate())) {
+            throw DomainException.badRequest(ErrorCode.INVALID_DATE_RANGE,
+                    "meta_date_end must not be before meta_date");
+        }
+        // Mirrors chk_meta_date_end_only_for_range. API-only: the edit form clears the
+        // end field off-RANGE, so this branch closes the same 500 class for direct clients.
+        if (doc.getMetaDateEnd() != null && doc.getMetaDatePrecision() != DatePrecision.RANGE) {
+            throw DomainException.badRequest(ErrorCode.INVALID_DATE_RANGE,
+                    "meta_date_end is only allowed when meta_date_precision is RANGE");
+        }
+    }
+
     @Transactional
     public Document updateDocumentTags(UUID docId, List<String> tagNames) {
         Document doc = documentRepository.findById(docId)

backend/src/main/java/org/raddatz/familienarchiv/exception/ErrorCode.java

@@ -26,6 +26,8 @@ public enum ErrorCode {
     FILE_UPLOAD_FAILED,
     /** The uploaded file's content type is not supported (PDF/JPEG/PNG/TIFF only). 400 */
     UNSUPPORTED_FILE_TYPE,
+    /** A RANGE date is invalid: meta_date_end is before meta_date, or an end date is set without RANGE precision. 400 */
+    INVALID_DATE_RANGE,
 
     // --- Users ---
     /** A user with the given ID or username does not exist. 404 */

backend/src/main/java/org/raddatz/familienarchiv/exception/GlobalExceptionHandler.java

@@ -6,6 +6,7 @@ import io.sentry.Sentry;
 import jakarta.validation.ConstraintViolationException;
 import org.raddatz.familienarchiv.exception.DomainException;
 import org.raddatz.familienarchiv.exception.ErrorCode;
+import org.springframework.dao.DataIntegrityViolationException;
 import org.springframework.http.ResponseEntity;
 import org.springframework.http.converter.HttpMessageNotReadableException;
 import org.springframework.web.bind.MethodArgumentNotValidException;
@@ -64,6 +65,38 @@ public class GlobalExceptionHandler {
                 .body(new ErrorResponse(ErrorCode.VALIDATION_ERROR, ex.getReason()));
     }
 
+    /**
+     * Backstop for any database integrity violation that slips past the explicit upstream
+     * guards (e.g. a future constraint, or the import path emitting a bad range). Turns it into
+     * a clean 400 instead of a 500 + Sentry alert. The known date-range cases are caught upstream
+     * and never reach here; this only catches the unanticipated ones — so it logs the constraint
+     * NAME at WARN to stay debuggable, without re-leaking SQL and without branching the response
+     * on it (the response stays generic, which is the non-brittle part).
+     */
+    @ExceptionHandler(DataIntegrityViolationException.class)
+    public ResponseEntity<ErrorResponse> handleDataIntegrityViolation(DataIntegrityViolationException ex) {
+        // Log the constraint NAME only — schema metadata, safe for Loki, and enough to tell which
+        // constraint fired at 2am. Never pass `ex` / `ex.getMessage()`: those embed the SQL + the
+        // offending values (CWE-209). No Sentry: an integrity violation is a 400, not a system fault.
+        log.warn("Rejected a request that violated a database integrity constraint: {}", constraintNameOf(ex));
+        return ResponseEntity.badRequest()
+                .body(new ErrorResponse(ErrorCode.VALIDATION_ERROR, "The submitted data violated a database constraint"));
+    }
+
+    /**
+     * Returns the offending constraint's name from the cause chain, or {@code "unknown"}.
+     * Reads only the name (a non-sensitive schema identifier) — never the SQL or the values.
+     */
+    private static String constraintNameOf(Throwable ex) {
+        for (Throwable t = ex; t != null && t != t.getCause(); t = t.getCause()) {
+            if (t instanceof org.hibernate.exception.ConstraintViolationException cve
+                    && cve.getConstraintName() != null) {
+                return cve.getConstraintName();
+            }
+        }
+        return "unknown";
+    }
+
     @ExceptionHandler(Exception.class)
     public ResponseEntity<ErrorResponse> handleGeneric(Exception ex) {
         Sentry.captureException(ex);

backend/src/test/java/org/raddatz/familienarchiv/document/DocumentRepositoryTest.java

@@ -38,7 +38,10 @@ import java.util.Optional;
 import java.util.Set;
 import java.util.UUID;
 
+import org.springframework.dao.DataIntegrityViolationException;
+
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 @DataJpaTest
 @AutoConfigureTestDatabase(replace = AutoConfigureTestDatabase.Replace.NONE)
@@ -612,6 +615,48 @@ class DocumentRepositoryTest {
                 .isLessThanOrEqualTo(5);
     }
 
+    // ─── V69 date-range CHECK constraints (#678) ──────────────────────────────
+
+    @Test
+    void save_acceptsRange_whenEndEqualsStart() {
+        // chk_meta_date_end_after_start is end >= start, so equal dates are valid.
+        // Real Postgres + Flyway here (H2 would not enforce the CHECK) pins the
+        // app guard's isBefore semantics to the actual constraint — guards drift (AC2).
+        LocalDate day = LocalDate.of(1917, 1, 10);
+        Document saved = documentRepository.saveAndFlush(Document.builder()
+                .title("Gleicher Tag")
+                .originalFilename("gleicher_tag.pdf")
+                .status(DocumentStatus.UPLOADED)
+                .documentDate(day)
+                .metaDatePrecision(DatePrecision.RANGE)
+                .metaDateEnd(day)
+                .build());
+
+        Document found = documentRepository.findById(saved.getId()).orElseThrow();
+        assertThat(found.getDocumentDate()).isEqualTo(day);
+        assertThat(found.getMetaDateEnd()).isEqualTo(day);
+        assertThat(found.getMetaDatePrecision()).isEqualTo(DatePrecision.RANGE);
+    }
+
+    @Test
+    void save_rejectsRange_whenEndBeforeStart_atDbLevel() {
+        // The app guard normally intercepts this, so the DB CHECK never fires in practice.
+        // Persisting directly proves chk_meta_date_end_after_start actually rejects end < start
+        // (H2 would not) — if the app guard ever regresses, a bad row still can't reach the table,
+        // and this is exactly the violation the GlobalExceptionHandler backstop turns into a 400.
+        Document doc = Document.builder()
+                .title("Verdrehte Spanne")
+                .originalFilename("verdreht.pdf")
+                .status(DocumentStatus.UPLOADED)
+                .documentDate(LocalDate.of(1917, 1, 11))
+                .metaDatePrecision(DatePrecision.RANGE)
+                .metaDateEnd(LocalDate.of(1917, 1, 10))
+                .build();
+
+        assertThatThrownBy(() -> documentRepository.saveAndFlush(doc))
+                .isInstanceOf(DataIntegrityViolationException.class);
+    }
+
     // ─── seeding helpers ─────────────────────────────────────────────────────
 
     private Document uploaded(String title) {

backend/src/test/java/org/raddatz/familienarchiv/document/DocumentServiceTest.java

@@ -20,6 +20,7 @@ import org.raddatz.familienarchiv.document.MatchOffset;
 import org.raddatz.familienarchiv.document.SearchMatchData;
 import org.raddatz.familienarchiv.tag.TagOperator;
 import org.raddatz.familienarchiv.exception.DomainException;
+import org.raddatz.familienarchiv.exception.ErrorCode;
 import org.raddatz.familienarchiv.document.Document;
 import org.raddatz.familienarchiv.document.DocumentStatus;
 import org.raddatz.familienarchiv.person.Person;
@@ -203,10 +204,12 @@ class DocumentServiceTest {
         // Editing a doc (e.g. fixing a location typo) without touching the precision
         // controls must NOT fabricate a precision. The form omits the three precision
         // fields → they arrive null on the DTO → the stored values must be preserved.
+        // Stored combo is RANGE + end: the only DB-valid way to have a non-null end
+        // (chk_meta_date_end_only_for_range), so the carried-over state passes the guard.
         UUID id = UUID.randomUUID();
         Document doc = Document.builder()
                 .id(id)
-                .metaDatePrecision(DatePrecision.MONTH)
+                .metaDatePrecision(DatePrecision.RANGE)
                 .metaDateEnd(LocalDate.of(1916, 6, 30))
                 .metaDateRaw("Juni 1916")
                 .receivers(new HashSet<>())
@@ -220,11 +223,119 @@ class DocumentServiceTest {
 
         documentService.updateDocument(id, dto, null, null);
 
-        assertThat(doc.getMetaDatePrecision()).isEqualTo(DatePrecision.MONTH);
+        assertThat(doc.getMetaDatePrecision()).isEqualTo(DatePrecision.RANGE);
         assertThat(doc.getMetaDateEnd()).isEqualTo(LocalDate.of(1916, 6, 30));
         assertThat(doc.getMetaDateRaw()).isEqualTo("Juni 1916");
     }
 
+    // ─── updateDocument date-range validation (#678) ──────────────────────────
+
+    /** Builds a stored doc ready for an updateDocument call (collections initialised). */
+    private static Document docForRangeUpdate(UUID id) {
+        return Document.builder().id(id).receivers(new HashSet<>()).tags(new HashSet<>()).build();
+    }
+
+    private static DocumentUpdateDTO rangeDto(LocalDate start, LocalDate end) {
+        DocumentUpdateDTO dto = new DocumentUpdateDTO();
+        dto.setDocumentDate(start);
+        dto.setMetaDatePrecision(DatePrecision.RANGE);
+        dto.setMetaDateEnd(end);
+        return dto;
+    }
+
+    @Test
+    void updateDocument_rejectsRange_whenEndBeforeStart() {
+        UUID id = UUID.randomUUID();
+        Document doc = docForRangeUpdate(id);
+        when(documentRepository.findById(id)).thenReturn(Optional.of(doc));
+
+        DocumentUpdateDTO dto = rangeDto(LocalDate.of(1917, 1, 11), LocalDate.of(1917, 1, 10));
+
+        assertThatThrownBy(() -> documentService.updateDocument(id, dto, null, null))
+                .isInstanceOf(DomainException.class)
+                .extracting(e -> ((DomainException) e).getCode())
+                .isEqualTo(ErrorCode.INVALID_DATE_RANGE);
+        verify(documentRepository, never()).save(any());
+    }
+
+    @Test
+    void updateDocument_acceptsRange_whenEndEqualsStart() throws Exception {
+        // AC2: the DB CHECK is end >= start, so equal dates are valid.
+        UUID id = UUID.randomUUID();
+        Document doc = docForRangeUpdate(id);
+        when(documentRepository.findById(id)).thenReturn(Optional.of(doc));
+        when(documentRepository.save(any())).thenReturn(doc);
+
+        LocalDate same = LocalDate.of(1917, 1, 10);
+        documentService.updateDocument(id, rangeDto(same, same), null, null);
+
+        assertThat(doc.getMetaDateEnd()).isEqualTo(same);
+        verify(documentRepository, atLeastOnce()).save(any());
+    }
+
+    @Test
+    void updateDocument_acceptsRange_whenEndAfterStart() throws Exception {
+        UUID id = UUID.randomUUID();
+        Document doc = docForRangeUpdate(id);
+        when(documentRepository.findById(id)).thenReturn(Optional.of(doc));
+        when(documentRepository.save(any())).thenReturn(doc);
+
+        documentService.updateDocument(id,
+                rangeDto(LocalDate.of(1917, 1, 10), LocalDate.of(1917, 1, 11)), null, null);
+
+        assertThat(doc.getMetaDateEnd()).isEqualTo(LocalDate.of(1917, 1, 11));
+        verify(documentRepository, atLeastOnce()).save(any());
+    }
+
+    @Test
+    void updateDocument_acceptsRange_whenEndIsNull_openEnded() throws Exception {
+        // AC3: an open-ended range (no end) is valid.
+        UUID id = UUID.randomUUID();
+        Document doc = docForRangeUpdate(id);
+        when(documentRepository.findById(id)).thenReturn(Optional.of(doc));
+        when(documentRepository.save(any())).thenReturn(doc);
+
+        documentService.updateDocument(id,
+                rangeDto(LocalDate.of(1917, 1, 10), null), null, null);
+
+        verify(documentRepository, atLeastOnce()).save(any());
+    }
+
+    @Test
+    void updateDocument_acceptsRange_whenStartNullAndEndSet() throws Exception {
+        // AC4: mirrors the DB "meta_date IS NULL" escape — must NOT reject (and must not NPE).
+        UUID id = UUID.randomUUID();
+        Document doc = docForRangeUpdate(id);
+        when(documentRepository.findById(id)).thenReturn(Optional.of(doc));
+        when(documentRepository.save(any())).thenReturn(doc);
+
+        documentService.updateDocument(id,
+                rangeDto(null, LocalDate.of(1917, 1, 11)), null, null);
+
+        assertThat(doc.getMetaDateEnd()).isEqualTo(LocalDate.of(1917, 1, 11));
+        verify(documentRepository, atLeastOnce()).save(any());
+    }
+
+    @Test
+    void updateDocument_rejectsEndDate_whenPrecisionNotRange() {
+        // AC6: an end date only makes sense for RANGE (mirrors chk_meta_date_end_only_for_range).
+        // API-only — the edit form clears the end field off-RANGE — so close the 500 class here too.
+        UUID id = UUID.randomUUID();
+        Document doc = docForRangeUpdate(id);
+        when(documentRepository.findById(id)).thenReturn(Optional.of(doc));
+
+        DocumentUpdateDTO dto = new DocumentUpdateDTO();
+        dto.setDocumentDate(LocalDate.of(1917, 1, 10));
+        dto.setMetaDatePrecision(DatePrecision.MONTH);
+        dto.setMetaDateEnd(LocalDate.of(1917, 1, 31));
+
+        assertThatThrownBy(() -> documentService.updateDocument(id, dto, null, null))
+                .isInstanceOf(DomainException.class)
+                .extracting(e -> ((DomainException) e).getCode())
+                .isEqualTo(ErrorCode.INVALID_DATE_RANGE);
+        verify(documentRepository, never()).save(any());
+    }
+
     // ─── deleteTagCascading ───────────────────────────────────────────────────
 
     @Test

backend/src/test/java/org/raddatz/familienarchiv/exception/GlobalExceptionHandlerTest.java

@@ -1,11 +1,17 @@
 package org.raddatz.familienarchiv.exception;
 
+import ch.qos.logback.classic.Level;
+import ch.qos.logback.classic.Logger;
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.read.ListAppender;
 import io.sentry.Sentry;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.InjectMocks;
 import org.mockito.MockedStatic;
 import org.mockito.junit.jupiter.MockitoExtension;
+import org.slf4j.LoggerFactory;
+import org.springframework.dao.DataIntegrityViolationException;
 import org.springframework.http.ResponseEntity;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -30,4 +36,84 @@ class GlobalExceptionHandlerTest {
             assertThat(response.getBody().code()).isEqualTo(ErrorCode.INTERNAL_ERROR);
         }
     }
+
+    @Test
+    void handleDataIntegrityViolation_returns400_withoutLeakingConstraint_orSentry() {
+        // A DataIntegrityViolationException carries the constraint name + SQL in its message;
+        // the response and logs must never echo it (CWE-209). It must become a clean 400, not a 500.
+        DataIntegrityViolationException ex = new DataIntegrityViolationException(
+                "could not execute statement; constraint [chk_meta_date_end_after_start]; "
+                        + "column meta_date_end of relation documents");
+
+        Logger handlerLogger = (Logger) LoggerFactory.getLogger(GlobalExceptionHandler.class);
+        ListAppender<ILoggingEvent> appender = new ListAppender<>();
+        appender.start();
+        handlerLogger.addAppender(appender);
+
+        try (MockedStatic<Sentry> sentryMock = mockStatic(Sentry.class)) {
+            ResponseEntity<GlobalExceptionHandler.ErrorResponse> response =
+                    handler.handleDataIntegrityViolation(ex);
+
+            assertThat(response.getStatusCode().value()).isEqualTo(400);
+            assertThat(response.getBody()).isNotNull();
+            assertThat(response.getBody().code()).isEqualTo(ErrorCode.VALIDATION_ERROR);
+            assertThat(response.getBody().message())
+                    .doesNotContain("chk_")
+                    .doesNotContain("meta_date");
+
+            // Defense-in-depth: an unanticipated integrity violation is not a system fault,
+            // so it must NOT fabricate a Sentry alert.
+            sentryMock.verifyNoInteractions();
+        } finally {
+            handlerLogger.detachAppender(appender);
+        }
+
+        assertThat(appender.list)
+                .as("logs a WARN line")
+                .anySatisfy(e -> assertThat(e.getLevel()).isEqualTo(Level.WARN));
+        assertThat(appender.list)
+                .as("never logs the SQL statement / values (would re-leak to Loki)")
+                .noneSatisfy(e -> {
+                    assertThat(e.getFormattedMessage()).contains("could not execute statement");
+                });
+    }
+
+    @Test
+    void handleDataIntegrityViolation_logsConstraintName_butNotTheSql() {
+        // Debuggability (DevOps): the WARN must name *which* constraint fired so an
+        // unanticipated violation isn't a silent mystery — but it must carry the name only,
+        // never the SQL statement or the offending values that the SQLException message holds.
+        java.sql.SQLException sql = new java.sql.SQLException(
+                "ERROR: violates check constraint; could not execute statement; values (1917-01-10)");
+        org.hibernate.exception.ConstraintViolationException cve =
+                new org.hibernate.exception.ConstraintViolationException(
+                        "constraint violation", sql, "chk_meta_date_end_after_start");
+        DataIntegrityViolationException ex = new DataIntegrityViolationException("wrapper", cve);
+
+        Logger handlerLogger = (Logger) LoggerFactory.getLogger(GlobalExceptionHandler.class);
+        ListAppender<ILoggingEvent> appender = new ListAppender<>();
+        appender.start();
+        handlerLogger.addAppender(appender);
+
+        try (MockedStatic<Sentry> sentryMock = mockStatic(Sentry.class)) {
+            ResponseEntity<GlobalExceptionHandler.ErrorResponse> response =
+                    handler.handleDataIntegrityViolation(ex);
+
+            // Response stays generic and leak-free (CWE-209) regardless of what we log.
+            assertThat(response.getStatusCode().value()).isEqualTo(400);
+            assertThat(response.getBody().message())
+                    .doesNotContain("chk_")
+                    .doesNotContain("meta_date");
+            sentryMock.verifyNoInteractions();
+        } finally {
+            handlerLogger.detachAppender(appender);
+        }
+
+        assertThat(appender.list)
+                .as("WARN names the constraint for debuggability")
+                .anySatisfy(e -> assertThat(e.getFormattedMessage()).contains("chk_meta_date_end_after_start"));
+        assertThat(appender.list)
+                .as("but never the SQL statement or values")
+                .noneSatisfy(e -> assertThat(e.getFormattedMessage()).contains("could not execute statement"));
+    }
 }

frontend/messages/de.json

@@ -655,6 +655,7 @@
 	"person_alias_btn_delete": "Entfernen",
 	"error_alias_not_found": "Der Namensalias wurde nicht gefunden.",
 	"error_invalid_person_type": "Der angegebene Personentyp ist ungültig.",
+	"error_invalid_date_range": "Das Enddatum darf nicht vor dem Startdatum liegen.",
 	"validation_last_name_required": "Nachname ist Pflichtfeld.",
 	"validation_first_name_required": "Vorname ist Pflichtfeld.",
 	"error_ocr_service_unavailable": "Der OCR-Dienst ist nicht verfügbar.",

frontend/messages/en.json

@@ -655,6 +655,7 @@
 	"person_alias_btn_delete": "Remove",
 	"error_alias_not_found": "The name alias was not found.",
 	"error_invalid_person_type": "The specified person type is not valid.",
+	"error_invalid_date_range": "The end date must not be before the start date.",
 	"validation_last_name_required": "Last name is required.",
 	"validation_first_name_required": "First name is required.",
 	"error_ocr_service_unavailable": "The OCR service is not available.",

frontend/messages/es.json

@@ -655,6 +655,7 @@
 	"person_alias_btn_delete": "Eliminar",
 	"error_alias_not_found": "No se encontro el alias de nombre.",
 	"error_invalid_person_type": "El tipo de persona especificado no es válido.",
+	"error_invalid_date_range": "La fecha final no puede ser anterior a la inicial.",
 	"validation_last_name_required": "El apellido es obligatorio.",
 	"validation_first_name_required": "El nombre es obligatorio.",
 	"error_ocr_service_unavailable": "El servicio OCR no está disponible.",

frontend/src/lib/document/WhoWhenSection.svelte

@@ -70,6 +70,13 @@ onMount(() => {
 
 const dateInvalid = $derived(dateDirty && dateDisplay.length > 0 && dateIso === '');
 
+// Inline mirror of the server guard (#678). ISO YYYY-MM-DD strings compare
+// lexicographically, so no Date object is needed. Server stays the gate —
+// this only surfaces the error early; it never disables Save.
+const endBeforeStart = $derived(
+	showEndDate && endDateIso !== '' && dateIso !== '' && endDateIso < dateIso
+);
+
 function handleDateInput(e: Event) {
 	const result = handleGermanDateInput(e);
 	dateDisplay = result.display;
@@ -155,8 +162,19 @@ $effect(() => {
 							oninput={handleEndDateInput}
 							placeholder={m.form_placeholder_date()}
 							maxlength="10"
-							class="block min-h-[48px] w-full rounded border border-line px-2 py-3 text-sm shadow-sm focus:outline-none focus-visible:ring-2 focus-visible:ring-focus-ring"
+							aria-invalid={endBeforeStart ? 'true' : undefined}
+							aria-describedby={endBeforeStart ? 'end-date-error' : undefined}
+							class="block min-h-[48px] w-full rounded border border-line px-2 py-3 text-sm shadow-sm
+                       {endBeforeStart
+								? 'border-red-400 focus:outline-none focus-visible:ring-2 focus-visible:ring-red-500'
+								: 'focus:outline-none focus-visible:ring-2 focus-visible:ring-focus-ring'}"
 						/>
+						{#if endBeforeStart}
+							<!-- Non-colour cue (WCAG 1.4.1): warning glyph + text, not red alone. -->
+							<p id="end-date-error" class="mt-1 text-xs text-red-600">
+								<span aria-hidden="true">⚠ </span>{m.error_invalid_date_range()}
+							</p>
+						{/if}
 					</div>
 				{/if}
 			</div>

frontend/src/lib/document/WhoWhenSection.svelte.test.ts

@@ -102,3 +102,49 @@ describe('WhoWhenSection — precision controls', () => {
 		expect(raw?.querySelector('b')).toBeNull();
 	});
 });
+
+describe('WhoWhenSection — end-before-start inline validation (#678)', () => {
+	it('shows an inline error on the end-date field when end is before start (AC1)', async () => {
+		render(WhoWhenSection, {
+			precision: 'RANGE',
+			dateIso: '1917-01-11',
+			endDateIso: '1917-01-10'
+		});
+
+		const end = document.querySelector('input#metaDateEnd') as HTMLInputElement;
+		await vi.waitFor(() => {
+			expect(document.querySelector('#end-date-error')).not.toBeNull();
+			expect(end.getAttribute('aria-invalid')).toBe('true');
+			expect(end.className).toContain('border-red-400');
+		});
+	});
+
+	it('clears the inline error once the end date is corrected, without reload (AC5)', async () => {
+		render(WhoWhenSection, {
+			precision: 'RANGE',
+			dateIso: '1917-01-11',
+			endDateIso: '1917-01-10'
+		});
+
+		await vi.waitFor(() => expect(document.querySelector('#end-date-error')).not.toBeNull());
+
+		const end = document.querySelector('input#metaDateEnd') as HTMLInputElement;
+		end.value = '12.01.1917'; // now after the start
+		end.dispatchEvent(new Event('input', { bubbles: true }));
+
+		await vi.waitFor(() => {
+			expect(document.querySelector('#end-date-error')).toBeNull();
+			expect(end.getAttribute('aria-invalid')).not.toBe('true');
+		});
+	});
+
+	it('does not show the inline error when precision is not RANGE', async () => {
+		render(WhoWhenSection, {
+			precision: 'DAY',
+			dateIso: '1917-01-11',
+			endDateIso: '1917-01-10'
+		});
+
+		expect(document.querySelector('#end-date-error')).toBeNull();
+	});
+});

frontend/src/lib/shared/errors.ts

@@ -8,6 +8,7 @@ export type ErrorCode =
 	| 'PERSON_NOT_FOUND'
 	| 'ALIAS_NOT_FOUND'
 	| 'INVALID_PERSON_TYPE'
+	| 'INVALID_DATE_RANGE'
 	| 'DOCUMENT_NOT_FOUND'
 	| 'DOCUMENT_NO_FILE'
 	| 'FILE_NOT_FOUND'
@@ -87,6 +88,8 @@ export function getErrorMessage(code: ErrorCode | string | undefined): string {
 			return m.error_alias_not_found();
 		case 'INVALID_PERSON_TYPE':
 			return m.error_invalid_person_type();
+		case 'INVALID_DATE_RANGE':
+			return m.error_invalid_date_range();
 		case 'DOCUMENT_NOT_FOUND':
 			return m.error_document_not_found();
 		case 'DOCUMENT_NO_FILE':