Gorm Cannot add several OnConflict clauses

GORM Playground Link

https://github.com/go-gorm/playground/pull/559

Description

SQLite supports multiple OnConflict clauses with different conflict targets. But current Gorm's API doesn't seem to support that: if I call AddClause several times with different OnConflict values, the latter one just overwrites the former one, because clauses are stored in a map under their names.

I had to workaround it by "subclassing" the OnConflict struct and changing the subclass name to ON CONFLICT (with extra whitespace), so that it is properly recognized by SQLite but Gorm considers it a different clause type:

import "gorm.io/gorm/callbacks"
import "gorm.io/gorm/clause"

...
callbacks.RegisterDefaultCallbacks(db, &callbacks.Config{
    CreateClauses: []string{
        "INSERT",
        "VALUES",
        "ON CONFLICT ", // my injected OnConflict2 struct
        "ON CONFLICT", // the original OnConflict
        "RETURNING", // without adding it here it wasn't added to auto-generated queries for some reason
    },
})
...
type OnConflict2 struct{
    clause.OnConflict
}
func (oc OnConflict2) Name() string {
    return "ON CONFLICT "
}
...

func (m *MyModel) BeforeCreate(tx *gorm.DB) error {
    tx.Statement.AddClause(OnConflict2{clause.OnConflict{
        Columns: []clause.Column{{Name: "my_unique_column"}},
        DoUpdates: clause.AssignmentColumns([]string{
            "updated_at",
        }),
    }})
    tx.Statemenet.AddClause(OnConflict{
        Columns: []clause.Column{{Name: "id"}},
        UpdateAll: true,  // UpdateAll doesn't seem to work properly for OnConflict2
    })
    return nil
}

Comment From: github-actions[bot]

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Comment From: MarSoft

Added the playground link: https://github.com/go-gorm/playground/pull/559

Comment From: MarSoft

I understand that fixing this issue would likely require major rework of Gorm's internal architecture. But at least it should be properly documented, and I think some workarounds could be documented too. Maybe the one I used. Or maybe make clause.OnConflict struct support several targets somehow?..