[multi tenant + slug]: slug is unique for all the collection, ignoring the tenant

[llaz00]

Describe the Bug

It seems this bug has been closed by mistake #14801.

Adding the indexes, as suggested by you, is not enough for making it work, as the slug is still set to unique in database, so it still fails.
Dropping the index directly from the database is also not enough, as you can't use it along with the ensureIndexes option set to true, and also is not persistent as you can't deploy multiple instances of the code without making changes to the database.

Please re-consider this bug and possible fixes, such as being able to set unique to false when calling slugField() (so we can manually add the compound index), before the final fix that should be making it fully compatible with multi-tenant scenarios by default.

The referenced issue has more details of the line where the slug field is set to unique.

Link to the code that reproduces this issue

#14801

Reproduction Steps

1. Install/configure multi tenancy plugin
2. Create a collection with a slug field
3. Create 2 different tenants
4. Try to use the same slug for both tenants

Which area(s) are affected?

plugin: multi-tenant

Environment Info

Not relevant

[Darkbound]

We are now experimenting with Payload to incorporate it into our workflows, but we have the same issue, we can't really use this for Multi-tenancy for real customers and try to explain to them that they can't use "home" as a slug or "products", because someone else got there first...

[ivanBalinov9]

Hi everyone — I discovered that the issue with the unique slug requirement is caused by the page collection configuration, where slugField() is used by default.

{ name: 'publishedAt', type: 'date', admin: { position: 'sidebar', }, }, slugField()....

Instead of using the default slugField(), I created a custom slug field. This allows the validation to check whether a slug already exists within the same tenant, rather than enforcing global uniqueness across all pages.
Here’s the custom field I’m using:

 export const tenantSlugField = (): TextField => ({
  name: 'slug',
  type: 'text',
  required: true,
  index: true,
  admin: {
    position: 'sidebar',
  },
  hooks: {
    beforeValidate: [
      ({ value }) => {
        if (typeof value === 'string') {
          return value
            .toLowerCase()
            .replace(/ /g, '-')
            .replace(/[^\w-]+/g, '')
        }
        return value
      },
    ],
  },
  validate: async (value: string | string[] | null | undefined, options: any) => {
    const { data, req, id } = options

    if (!value || Array.isArray(value)) {
      return true
    }


    const tenantId = data?.tenant || req?.user?.tenant

    if (!tenantId) {

      return true
    }


    const existingPages = await req.payload.find({
      collection: 'pages',
      where: {
        and: [
          {
            slug: {
              equals: value,
            },
          },
          {
            tenant: {
              equals: tenantId,
            },
          },
        ],
      },
      limit: 1,
    })

  
    if (existingPages.docs.length > 0) {
      const existingPage = existingPages.docs[0]


      if (id && existingPage.id === id) {
        return true
      }


      return `A page with slug "${value}" already exists in this tenant`
    }

    return true
  },
})