Creating duplicate tags?

[aldo-roman]

Hello Medusa team,

I can see in database that ProductTags are unique by their value field.

What happens if I invoke createProductTags with a value that already exists? Does it throw an error? Is it skipped and the existing tag returned?

I coulnd't find this behaviour documented
See https://docs.medusajs.com/resources/references/product/createProductTags

Thanks!

[LysCongThanh]

It throws. It doesn't skip the duplicate or return the existing tag. createProductTags (product-module-service.ts) just passes the input to the internal service's create, with no lookup by value. The ProductTag model has a unique index on value that ignores soft-deleted rows (same on develop, v2.11.2 and v2.12.5):

.indexes([
  { name: "IDX_tag_value_unique", on: ["value"], unique: true, where: "deleted_at IS NULL" },
])

So Postgres rejects the insert with a unique violation, and the repository's dbErrorMapper (db-error-mapper.ts) turns it into a MedusaError of type invalid_data with a message of the form Product tag with value: foo, already exists.

upsertProductTags doesn't change that: items without an id go through the same create, items with an id go through update, and nothing is matched on value.

For get-or-create, list first and create only the missing values:

const existing = await productModule.listProductTags({ value: values })
const have = new Set(existing.map((t) => t.value))
const created = await productModule.createProductTags(
  values.filter((v) => !have.has(v)).map((value) => ({ value }))
)

A soft-deleted tag doesn't block creating a new one with the same value, because of the deleted_at IS NULL condition.

Not verified: I read this in the source but didn't run it, so the exact error text may differ slightly.