复合文字使用非键控字段

我和 Golang 的新官方 Mongodb 司机一起工作。我创建了一个复杂的查询,将数据插入 mongodb,然后根据元素值对其进行排序。我正在使用一个过滤器,其中我已经创建了 bson 类型使用:-

filter := bson.D{{"autorefid", "100"}}

不过,它也发出了一个警告:

E 复合文字使用非键控字段

这些警告正在我的代码中制造混乱。

71697 次浏览

The warnings can be stopped by setting the check flag to false.

$ go doc cmd/vet

By default all checks are performed. If any flags are explicitly set to true, only those tests are run. Conversely, if any flag is explicitly set to false, only those tests are disabled. Thus -printf=true runs the printf check, -printf=false runs all checks except the printf check.

Unkeyed composite literals


Flag: -composites


Composite struct literals that do not use the field-keyed syntax.

But the warning is due to not providing the keys name when setting the value in primitive.E struct.

Setting keys for primitive.E struct will remove the warning messages. For example

filter := bson.D{primitive.E{Key: "autorefid", Value: "100"}}

Package primitive contains types similar to Go primitives for BSON types can do not have direct Go primitive representations.

type E struct {
Key   string
Value interface{}
}

E represents a BSON element for a D. It is usually used inside a D.

For more information have a look at primitive.E

You can change:

filter := bson.D\{\{"autorefid", "100"}}

to:

filter := bson.D{primitive.E{Key: "autorefid", Value: "100"}}

You can simply change:

filter := bson.D\{\{"autorefid", "100"}}

to:

filter := bson.D\{\{Key: "autorefid", Value: "100"}}

//Skip primitive.E as said by Chris W

Since no one else has pointed this out — the warning is there to safeguard you from changes in the third-party API breaking your code silently.

Ignoring this vet warning has the potential to lead to really nasty and hard to track down runtime bugs, so you'd be better off if you were to always specify the keys of 3rd party structs explicitly.

Such would be the case if the maintainers of the library you are using decided to change the order of elements in their struct for whatever reason. For example, switching Key with Value, in the OP case. Your code would still appear to compile just fine, but what you intended to be the key would now be passed as the value and vice versa, and things would just start breaking in unexpected ways.

Actually, if ordered representation of a BSON document doesn't necessary you can change your BSON document to unordered representation by simply change

filter := bson.D\{\{"autorefid", "100"}}

to

filter := bson.M{"autorefid": "100"}

See this stackoverflow answer for more details about bson.D vs bson.M. The MongoDB server is smart enough to find matching indices regardless of the used order.

If you are using vscode try disable the following in settings:

enter image description here