Gorm Unique field always causes field migration

GORM Playground Link

No time to make it for now.

Description

unique Field (having uniqueIndex or index:,unique tag) always causes migration.

The reason is this line:

https://github.com/go-gorm/gorm/blob/7da24d1d52be944fe5058792f8bdcf9572b48a1f/schema/field.go#L116

field.Unique is only true when tagSettings["UNIQUE"] is true.

But uniqueIndex tag only sets tagSettings["UNIQUEINDEX"] and index tag only sets tagSettings["INDEX"].

And field migration is checking field.Unique in this line:

https://github.com/go-gorm/gorm/blob/7da24d1d52be944fe5058792f8bdcf9572b48a1f/migrator/migrator.go#L481

Therefore field migration will always be performed.

Maybe schema/field.go#L116 should be changed to

field := &Field{
    ...,
    Unique: false,
}
if indexes, err := parseFieldIndexes(field); err == nil {
    for _, index := range indexes {
        if index.Class == "UNIQUE" {
            field.Unique = true
            break
        }
    }
}

But I don't think this treatment is good. Does field.Unique deserve to exist?

Comment From: github-actions[bot]

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Comment From: github-actions[bot]

Comment From: Nomango

Seems like #5942 is the same issue.

Comment From: github-actions[bot]

Comment From: jinzhu

Should be fixed in commit https://github.com/go-gorm/gorm/commit/3d91802b1d1bd5ad175ac43fac062fd9f8de98be