Locale-Aware Relation Sync: Fill Locales Without Breaking Relations

[Weegy]

Overview

No headless CMS handles locale fill correctly when content contains relations. When you "copy from locale" in Strapi, Payload, or Directus, relational fields either break (get nullified) or point to the wrong-locale variant of the related entity.

Numen can solve this with locale-aware relation re-linking at sync time.

The Problem (Competitor Evidence)

Strapi #25703 (March 11, 2026, active PR): "fix: preserve relations in fill from another locale" — 4 comments, unmerged. When using "fill from locale" in Strapi, relation fields are dropped entirely. You fill your French content from English, but all the related categories, authors, and tags point to the English variants — or are null.

The same issue exists in Directus i18n — their translations module requires manually re-linking relations per locale.

Why it's hard: "Copy locale A → locale B" seems simple until relations are involved:

• Related entity may have a locale-B translation (should auto-link it)
• Related entity may NOT have a locale-B translation (should flag it, not null it)
• Relation may be many-to-many (each item needs independent locale resolution)
• User may want to override (keep the locale-A related item intentionally)

Proposed Solution: Locale-Aware Relation Sync

Sync Algorithm

When filling locale B from locale A:

1. Detect all relation fields in the content type schema
2. For each related entity, check if a locale-B translation exists
3. Auto-resolve: If locale-B translation exists → auto-link it
4. Flag: If no locale-B translation exists → create a LocaleSyncFlag entry ("Related item 'Tag: News' has no French translation")
5. Preserve override: If user has manually set a relation in locale B → don't overwrite (respect manual edits)

UI Diff Preview

Before applying locale fill, show a diff:

✅ Author: John Doe → Jean Dupont (FR translation found, auto-linked)
⚠️  Category: "Breaking News" → no FR translation (will keep EN relation, flagged)
✅ Tags: [3 tags] → [3 FR tag variants found, auto-linked]
❌  Related Content: "Article A" → no FR version (relation will be null — create translation first)

User can override any decision before confirming.

Knowledge Graph Integration

Numen's knowledge graph tracks content relationships across locales. The sync engine queries the graph to find locale variants of related entities — this is a natural capability extension, not a separate feature.

API Endpoint

POST /api/content/{id}/locale-sync
{
  "from_locale": "en",
  "to_locale": "fr",
  "dry_run": true,    // Returns diff without applying
  "strategy": {
    "missing_translation": "flag",  // or "null", "keep_source"
    "respect_manual": true
  }
}

Why This Matters

Teams managing 5+ locales waste hours per content type re-linking relations manually. Numen's locale-aware sync turns a 30-minute per-locale task into a 30-second one — with a clear audit trail.

Priority

HIGH — Multilingual content teams are a key Numen target market. Ghost's i18n mega-issue (30+ comments) shows this is an unresolved pain across the industry. Numen already ships i18n — this makes it meaningfully better.

Competitor Status

CMS	Locale fill behavior	Relation handling
Strapi	"Fill from locale" feature	Drops relations (open bug #25703)
Directus	Manual translation per locale	Manual re-linking required
Payload	Localization built-in	Relation locale resolution inconsistent
Ghost	No native multilingual	N/A
Numen	Locale-aware sync with relation re-linking	Auto-resolve + flag + diff preview