There are multiple good constructors and room will problem

problem ：

kotlin Update value 1.2.6 version ,room The entity class of the table fails to compile , such as ：

@Entity(tableName = "table_hex")
data class HexData constructor( @ColumnInfo(name = "id")
        @PrimaryKey(autoGenerate = true)
        var id: Int = 0,
        @ColumnInfo(name = "code")
        var code: String = "",
        @ColumnInfo(name = "datas")
        var datas: String = "") {
    constructor() : this(0)
}

The following warnings and exceptions will appear

Warning:(11, 2)  Warning : There are multiple good constructors and Room will pick the no-arg construct

When a new field is added , It will fail to compile , Can't find setter Method , In fact, it was all caused by the above warning

solve ：

Add... To the constructor Ignore Annotations can be

@Entity(tableName = "table_hex")
data class HexData constructor( @ColumnInfo(name = "id")
        @PrimaryKey(autoGenerate = true)
        var id: Int = 0,
        @ColumnInfo(name = "code")
        var code: String = "",
        @ColumnInfo(name = "datas")
        var datas: String = "") {
    @Ignore
    constructor() : this(0)
}