I18n and slug system

System Information
  • Strapi Version: 3.6.0

So I just updated to the latest Strapi version, 3.6.0, and followed the guide to create localization for my content. I also use a slug system from the official documentation. I created a slug based on a title field. So, for example, I have a collection type ‘Category’, with title ‘Animals’, I got a slug ‘animas’. And I used this GraphQL query to fetch a category by slug:

query Categories($slug:String!) {
  categories(where: {slug: $slug}) {

Now I added Italian locale, and for Italian, I changed the title to ‘Animali’, which also created a slug ‘animali’ for that Category.

However, when I run the query above with this slug, I’m getting no results. If I manually change it to ‘animals’ - I do receive the Category.

Is it a bug or am I doing something wrong?

OK, so apparently I have to pass also a locale to the query in order for that to work:

query Categories($slug:String!, $locale:String! = "all") {
  categories(where: {slug: $slug}, locale: $locale) {

But now I ran into another 2 problems:

  1. in my Category I have a relation field, Bars, with the following rule: “Categories has and belongs to many Bars”. Obviously, all Bars belonged to a Category with the default EN locale. Now that I’ve added locales to Ctegories, the relations weren’t copied also to these locales. So is there a way to a) copy all the relations to the new locales and b) make sure that once I add a new Bar to the relation, it will be added to all the locales?

  2. I tried to add ‘localizations’ to the query
    query Categories($slug:String!, $locale:String! = “all”) {
    categories(where: {slug: $slug}, locale: $locale) {

    localizations: {

And I received the following error:
“Cast to ObjectId failed for value “[object Object]” at path “_id” for model “category””
In fact, I received this error on every query where I tried it. Why is this error happening?

If you replace locale: $locale with _locale: "all" then you’ll get your main page, plus an array of the localized pages in localizations. Not sure if that’s what you were looking for, but thought it might be helpful. The documentation doesn’t make this clear at all.

And I just found out that a query like this will return just the page for the language you request without having to deal with the localizations array when your slug matches across languages.

  pages (
    where: { 
    	path: "/jars", 
      locale: "es-MX",
      _locale: "all" },
 	 limit: 1 ) {