Fix N+1 translation cache lookups in celery translation tasks

[szabozoltan69]

For Sentry issue /organizations/ifrc-go/issues/5764

[thenav56]

Thanks @szabozoltan69 for integrating with cache table.

[thenav56]

Maybe we can refactor the whole function with the new cache logic.
Something like this

def translate_fields_object(self, obj, field):
    initial_lang = getattr(obj, TRANSLATOR_ORIGINAL_LANGUAGE_FIELD_NAME)
    initial_value = getattr(obj, build_localized_fieldname(field, initial_lang), None)
    if not initial_value or not initial_lang:
        return

    model = type(obj)
    table_field = f"{model._meta.app_label}:{model._meta.model_name}:{field}"
    field_max_length = model._meta.get_field(field).max_length

    # Determine which languages still need translation
    pending_langs = {
        lang: build_localized_fieldname(field, lang)
        for lang in AVAILABLE_LANGUAGES
        if not getattr(obj, build_localized_fieldname(field, lang), None)
    }
    if not pending_langs:
        return

    # Batch-fetch cached translations for all pending languages at once
    cached = self.translator.get_cached_translations(
        initial_value,
        list(pending_langs.keys()),
        source_language=initial_lang,
        table_field=table_field,
    )

    for lang, lang_field in pending_langs.items():
        translated = cached.get(lang) or self.translator.translate_text(
            initial_value,
            lang,
            source_language=initial_lang,
            table_field=table_field,
        )

        if translated is None:
            logger.warning(
                "Translation failed for %s.%s pk=%s",
                model.__name__,
                lang_field,
                obj.pk,
            )
            continue

        if field_max_length and len(translated) > field_max_length:
            logger.warning(
                "Translation exceeds max_length (%d) for %s.%s pk=%s",
                field_max_length, model.__name__, lang_field, obj.pk,
            )
            translated = translated[:field_max_length]

        setattr(obj, lang_field, translated)
        yield lang_field

I haven't tested this.

[thenav56]

if not caches will be always be true as caches is a queryset object.

We can instead use cache_by_lang for if

Suggested change

	if not caches:
	return {}
	cache_by_lang = {cache.dest_language: cache for cache in caches}
	cache_by_lang = {cache.dest_language: cache for cache in caches}
	if not cache_by_lang:
	return {}