为什么我的更新函数返回新查询但不更新数据库？

I am creating a RESTful API and am in the process of creating an update function. I use FindOneAndUpdate, and it doesn't actually update the database.

I have tried many things, but I'm fairly new to the language so I'm a bit lost.

func UpdateCompanyEndpoint(response http.ResponseWriter, request *http.Request) {
    response.Header().Set("content-type", "application/json")
    params := mux.Vars(request)
    name, _ := params["name"]
    var company Company
    _ = json.NewDecoder(request.Body).Decode(&company)
    collection := client.Database("RESTful").Collection("companies")
    ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
    defer cancel()
    filter := bson.D{{"name", name}}
    update := bson.D{{"$set", bson.D{{"application", company.Application}}}}
    err := collection.FindOneAndUpdate(
        ctx,
        filter,
        update).Decode(&company)
    if err == nil {
        response.WriteHeader(http.StatusInternalServerError)
        return
    }
    json.NewEncoder(response).Encode(company)
}

[
    {
        "name": "Test1",
        "application": "Test1"
    },
    {
        "name": "Test2",
        "application": "Test2"
    },
    {
        "name": "Test3",
        "application": "Test3"
    }
]

This is the current database. When I call the function, it returns:

{
    "name": "Test2",
    "application": "Test2update"
}

but the database remains unchanged.

Your problem is in this block:

if err == nil {
    response.WriteHeader(http.StatusInternalServerError)
    return
}
json.NewEncoder(response).Encode(company)

Notice carefully, you are sending StatusInternalServerError is err is nil, and you get the response you posted when err != nil, so some error is occuring in your case.