fix(seo): keep whole words when truncating slugs, detect unique violations as Prisma errors

src/services/slug/slug.service.spec.ts

@@ -1,6 +1,6 @@
 import { BadRequestException, ConflictException, Logger, NotFoundException } from '@nestjs/common';
 import { SlugService } from './slug.service';
-import { SlugEntityType } from '../../../prisma/generated/client';
+import { Prisma, SlugEntityType } from '../../../prisma/generated/client';
 import { SlugCandidateRow } from '../../database/slug.database.repository';
 
 const row = (hiboutikId: number, name: string): SlugCandidateRow => ({ id: `uuid-${hiboutikId}`, hiboutikId, name });
@@ -93,10 +93,22 @@ describe('SlugService', () => {
       slugDatabaseRepository.changeSlug.mockResolvedValueOnce('TAKEN');
       await expect(service.changeSlug(SlugEntityType.BRAND, 'uuid-1', 'bts')).rejects.toThrow(ConflictException);
 
-      slugDatabaseRepository.changeSlug.mockRejectedValueOnce(Object.assign(new Error('Unique constraint failed'), { code: 'P2002' }));
+      slugDatabaseRepository.changeSlug.mockRejectedValueOnce(
+        new Prisma.PrismaClientKnownRequestError('Unique constraint failed', { code: 'P2002', clientVersion: 'test' }),
+      );
       await expect(service.changeSlug(SlugEntityType.BRAND, 'uuid-1', 'bts')).rejects.toThrow(ConflictException);
     });
 
+    it('rethrows any other error, even one carrying a P2002 code without being a Prisma error', async () => {
+      const notPrisma = Object.assign(new Error('boom'), { code: 'P2002' });
+      slugDatabaseRepository.changeSlug.mockRejectedValueOnce(notPrisma);
+      await expect(service.changeSlug(SlugEntityType.BRAND, 'uuid-1', 'bts')).rejects.toBe(notPrisma);
+
+      const otherPrismaError = new Prisma.PrismaClientKnownRequestError('Record not found', { code: 'P2025', clientVersion: 'test' });
+      slugDatabaseRepository.changeSlug.mockRejectedValueOnce(otherPrismaError);
+      await expect(service.changeSlug(SlugEntityType.BRAND, 'uuid-1', 'bts')).rejects.toBe(otherPrismaError);
+    });
+
     it('accepts a valid new slug', async () => {
       slugDatabaseRepository.changeSlug.mockResolvedValue('CHANGED');
 

src/services/slug/slug.service.ts

@@ -1,5 +1,5 @@
 import { BadRequestException, ConflictException, Injectable, Logger, NotFoundException } from '@nestjs/common';
-import { SlugEntityType } from '../../../prisma/generated/client';
+import { Prisma, SlugEntityType } from '../../../prisma/generated/client';
 import { SlugCandidateRow, SlugDatabaseRepository } from '../../database/slug.database.repository';
 import { forEachSafely } from '../../utils/sync';
 import { MAX_SLUG_LENGTH, pickAvailableSlug, SLUG_PATTERN, slugify, withSlugSuffix } from '../../utils/slug';
@@ -17,6 +17,9 @@ const FALLBACK_PREFIX: Record<SlugEntityType, string> = {
  * A slug is generated once, when an entity has none, and is never regenerated: a URL must not change when the name
  * changes in Hiboutik. Generation is deterministic: entities are handled oldest first (by `hiboutikId`), so that a
  * database rebuilt from scratch gets the same slugs, the oldest of two homonyms keeping the plain slug.
+ * A rebuild only gives back the stored slugs as long as their history did not change them: a slug replaced by an admin,
+ * an entity renamed in Hiboutik after its slug was generated, or a homonym deleted since (the younger one, suffixed,
+ * would now get the plain slug) all give a different slug on a rebuild, and the redirects are lost with the database.
  * An admin can replace a slug ({@link changeSlug}): the former one is kept as a redirect.
  */
 @Injectable()
@@ -83,7 +86,7 @@ export class SlugService {
       result = await this.slugDatabaseRepository.changeSlug(type, id, slug);
     } catch (error) {
       // Unique constraint: the same slug was written at the same time by someone else
-      if ((error as { code?: string })?.code === 'P2002') result = 'TAKEN';
+      if (error instanceof Prisma.PrismaClientKnownRequestError && error.code === 'P2002') result = 'TAKEN';
       else throw error;
     }
     if (result === 'NOT_FOUND') throw new NotFoundException();

src/utils/slug.spec.ts

@@ -21,6 +21,12 @@ describe('slugify', () => {
     expect(slug.length).toBeLessThanOrEqual(MAX_SLUG_LENGTH);
     expect(slug).toMatch(SLUG_PATTERN);
   });
+
+  it('keeps the last word when the cut falls right before a hyphen', () => {
+    expect(slugify('aa bbb ccc', 6)).toBe('aa-bbb');
+    expect(slugify('aa bbb ccc', 7)).toBe('aa-bbb');
+    expect(slugify('aa bbb ccc', 5)).toBe('aa');
+  });
 });
 
 describe('withSlugSuffix', () => {

src/utils/slug.ts

@@ -15,7 +15,7 @@ const SPECIAL_LETTERS: Record<string, string> = { æ: 'ae', œ: 'oe', ø: 'o',
 export function slugify(name: string, maxLength = MAX_SLUG_LENGTH): string {
   const slug = name
     .normalize('NFKD')
-    .replace(/[̀-ͯ]/g, '')
+    .replace(/[\u0300-\u036f]/g, '')
     .toLowerCase()
     .replace(/[æœøßđłþ]/g, (letter) => SPECIAL_LETTERS[letter])
     .replace(/&/g, ' and ')
@@ -24,10 +24,14 @@ export function slugify(name: string, maxLength = MAX_SLUG_LENGTH): string {
   return truncateSlug(slug, maxLength);
 }
 
-/** Cuts a slug to `maxLength`, at the last hyphen when there is one, never leaving a trailing hyphen. */
+/**
+ * Cuts a slug to `maxLength` at a word boundary: keeps the cut as is when it ends on a whole word, else cuts at its last
+ * hyphen when there is one. Never leaves a trailing hyphen.
+ */
 function truncateSlug(slug: string, maxLength: number): string {
   if (slug.length <= maxLength) return slug;
   const cut = slug.slice(0, maxLength);
+  if (slug[maxLength] === '-') return cut;
   const lastHyphen = cut.lastIndexOf('-');
   return (lastHyphen > 0 ? cut.slice(0, lastHyphen) : cut).replace(/-+$/, '');
 }