Proposal: add Coerce method to Version type which takes a string into SemVer if possible

[Andrii Soldatenko]

something like:

// Coerce a string into SemVer if possible
func Coerce(version string) *semver.Version {
	v, err := semver.NewVersion(version)
	if err != nil {
		fmt.Println(err)
	}
	coerceVer, err := semver.NewVersion(fmt.Sprintf("%d.%d.%d", v.Major(), v.Minor(), v.Patch()))
	if err != nil {
		fmt.Println(err)
	}
	return coerceVer
}



func Test_coerce(t *testing.T) {
	assert.Equal(t, "1.10.5", coerce("1.10.5-11-alpine3.10-onbuild").String())
	assert.Equal(t, "1.10.5", coerce("1.10.5").String())
	assert.Equal(t, "1.10.12", coerce("1.10.12-buster").String())
}

inspired by node.js version https://www.npmjs.com/package/semver

Let me know if i can fire PR.

[Matt Farina]

What's the use case for Coerce? semver already has a NewVersion and StrictNewVersion. The first performs a minimal coerce and the second does not. For an example, see https://play.golang.org/p/zqjlWuyO0JT.

If you look at examples the coerce JS function works on... you'll see that NewVersion will throw an error. Like 42.6.7.9.3-alpha. This is where it gets interesting. In the Test_coerce function all 3 examples that go through coerce are valid SemVer. The two with pre-releases should not match the versions that don't have a pre-release.

What are you looking for a coerce function to do? Just perform the same duty the JS one does? I'm curious of the problem to be solved.

[Andrii Soldatenko]

What's the use case for Coerce? semver already has a NewVersion and StrictNewVersion. The first performs a minimal coerce and the second does not. For an example, see https://play.golang.org/p/zqjlWuyO0JT.

If you look at examples the coerce JS function works on... you'll see that NewVersion will throw an error. Like 42.6.7.9.3-alpha. This is where it gets interesting. In the Test_coerce function all 3 examples that go through coerce are valid SemVer. The two with pre-releases should not match the versions that don't have a pre-release.

What are you looking for a coerce function to do? Just perform the same duty the JS one does? I'm curious of the problem to be solved.

@mattfarina thanks for quick reply!

Use case is pretty simple: you have list of strings versions ["1.10.5-11-alpine3.10-onbuild", "1.10.5", "1.10.12-buster"] and valid min SemVer: e.g. 1.10.12 and goal is to filter list by that version and return:

["1.10.12-buster"]

yeah looks like it was my fault:

package main

import (
	"fmt"
	"github.com/Masterminds/semver/v3"
)

func main() {
	versions := []string{"1.10.5-11-alpine3.10-onbuild", "1.10.5", "1.10.12-buster", "1.10.12"}
	
	_ = versions
	targetVer, _ := semver.NewVersion("1.10.12-alpine")
	
	for _, version := range versions {
		v, _ := semver.NewVersion(version)
		if i := v.Compare(targetVer); i >= 0 {
			fmt.Println(v.String())
		}
		
	}
}

1.10.12-buster
1.10.12

so it works as expected. https://play.golang.org/p/If5d3Rmgozr