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This article introduces the relevant knowledge of "what are the new features of Go1.16". In the operation of actual cases, many people will encounter such a dilemma. Then let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

A few days ago, Go officially released version 1.16. From this version, the default value of the environment variable GO111MODULE is officially changed to on. This also means that Go modules will further promote its business coverage, and partners with new and old projects suggest manually adjusting GO111MODULE to auto.

Go1.16 has released a new feature for Go modules that gives developers who maintain third-party libraries (including Go mod) the right to take "regret pills" over and over again, reminding users of problems with released "dirty" versions and understanding the cause.

This new feature is a small boon for many partners who maintain and use public libraries (open source, enterprises, etc.). It is suggested that everyone should know this knowledge point.

It will be explained and introduced in detail in the following article.

Medicine for regret: Go mod retract

Go1.16 can use the retract directive in the go.mod file to declare that some distributions of this third-party module cannot be used by other modules.

In usage scenarios: after a serious problem is found or some version is unintentionally released, the maintenance author of the module can withdraw the version and support the withdrawal of single or multiple versions.

There was no way to solve it before, so once it appears, it will be very troublesome. The corresponding operations for both are as follows:

Maintainer:

Delete the problematic version of tag.

Retype a new version of tag.

Users:

It is found that the defective version of tag is missing and needs to be intervened manually.

Do not know that there is a problem, because other libraries rely on, so passive upgrade and step on the hole.

Therefore, after the release of this Go1.16, we have a new means of semi-stop loss, and it can also be used as one of the filling methods of the big pit automatically updated by Go mod.

Actual combat exercise

To facilitate the demonstration, first create a Demo project (github.com/eddycjy/go-retract-demo) that contains a basic method:

Package go_retract_demo func HelloWorld () string {return "001: fried fish in my head!" }

Another application project relies on the third-party library. The code is as follows:

Func main () {/ / import demo "github.com/eddycjy/go-retract-demo" s: = demo.HelloWorld () fmt.Println (s)}

The corresponding go.mod file is as follows:

Module github.com/eddycjy/awesomeProject go 1.16 require github.com/eddycjy/go-retract-demo v0.0.1

Retract feature demonstration

However, with the passage of time, when the third-party open source library eddycjy/go-retract-demo is about to iterate to v0.3.0, it is found that the previous v0.2.0 has BUG.

It is urgent to fix this BUG in v0.3.0 and remind it to go out. At this point, you can write the retract directive in the go.mod file:

Module github.com/eddycjy/go-retract-demo go 1.16 / because fried fish accidentally knocked wrong. Retract v0.2.0

The reason for the withdrawal is above the directive, followed by the specific version. If multiple versions are involved, you can write as follows:

Retract (v0.1.0 v0.2.0)

Retract characteristic effect

After successfully releasing the latest version v0.3.0 and specifying retract. For all engineering applications that reference the library, you can see the following reminder when you execute go list:

$go1.16 list-m-u all xxx/eddycjy/awesomeProject xxx/eddycjy/go-retract-demo v0.2.0 (retracted) [v0.3.0]

Combined with this command, the IDE we use on a daily basis (for example, GoLand) will execute the go list command by default when saving. With subsequent IDE support, you can quickly find problematic versions and prompts as you code.

The warning prompt also appears when you manually execute go get, which displays the reason comment on the go.mod file:

$go1.16 get github.com/eddycjy/go-retract-demo@v0.2.0 go: warning: github.com/eddycjy/go-retract-demo@v0.2.0: retracted by module author: because the fried fish accidentally knocked wrong. Go: to switch to the latest unretracted version, run: go get github.com/eddycjy/go-retract-demo@latest

This allows you to see which module is dependent and for what reason the request has been withdrawn, which is very intuitive.

Summary

In the past, after something went wrong, each individual had to ask the maintainer or watch the GitHub Commits, which was always very troublesome and was likely to be gone in half an hour.

The new features give Go modules a soft-withdrawn version of a way to more intuitively feedback problems to developers, which is even more beautiful when combined with day-to-day development tools.

However, there are some obstacles to the full application of this feature at present:

Domestic module agent: need domestic module agent to also support retract, otherwise there is no prompt to deal with it even if you update the version.

IDE:IDE does some support for retract, such as text color red, yellow, etc., which can be better recognized by developers.

That's all for "what are the new features of Go1.16"? thank you for reading. If you want to know more about the industry, you can follow the website, the editor will output more high-quality practical articles for you!

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