Atlas migrations add extra unique index on primary keys

[ivanvanderbyl]

After switching to Atlas for migrations, the first migration added an additional unique index on all id fields, even though there is already a primary key index.

• The issue is present in the latest release.
• I have searched the issues of this repository and believe that this is not a duplicate.

Current Behavior 😯

Switching to Atlas creates migrations such as:

CREATE UNIQUE INDEX "users_id_key" ON "users" ("id");

When users already has a primary key index:

Indexes:
    "users_pkey" PRIMARY KEY, btree (id)

Resulting in:

                                         Table "public.users"
       Column       |            Type             | Collation | Nullable |          Default
--------------------+-----------------------------+-----------+----------+----------------------------
 id                 | character varying           |           | not null |
Indexes:
    "users_pkey" PRIMARY KEY, btree (id)
    "users_id_key" UNIQUE, btree (id)

Expected Behavior 🤔

Atlas should recognise the primary key index and not create an additional index.

Steps to Reproduce 🕹

Usual Ent setup using custom IDs as strings.

func (User) Fields() []ent.Field {
	return []ent.Field{
		field.String("id").
			MaxLen(31).
			NotEmpty().
			Unique().
			DefaultFunc(UserIDFunc).
			Immutable(),
        ...
}

Your Environment 🌎

Tech	Version
Go	1.18.rc1
Ent	master
Atlas	master
Database	Postgres

[hehex9]

facing the same issue, any workaround?

[a8m]

Thanks for reporting this @ivanvanderbyl and @hehex9

Fixed with #2425