if IsValid(name) {
		return name
	}
	return FromToolchain(name)
}

// ToolchainMax returns the maximum of x and y interpreted as toolchain names,
// compared using Compare(FromToolchain(x), FromToolchain(y)).
// If x and y compare equal, Max returns x.
func ToolchainMax(x, y string) string {
	if Compare(FromToolchain(x), FromToolchain(y)) < 0 {
		return y
	}
	return x
}

	})
}

// ModIsValid reports whether vers is a valid version syntax for the module with the given path.
func ModIsValid(path, vers string) bool {
	if IsToolchain(path) {
		if path == "toolchain" {
			return IsValid(FromToolchain(vers))
		}
		return IsValid(vers)
	}
	return semver.IsValid(vers)
}

// ModIsPrefix reports whether v is a valid version syntax prefix for the module with the given path.

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package gover

import "testing"

func TestFromToolchain(t *testing.T) { test1(t, fromToolchainTests, "FromToolchain", FromToolchain) }

var fromToolchainTests = []testCase1[string, string]{
	{"go1.2.3", "1.2.3"},
	{"1.2.3", ""},
	{"go1.2.3+bigcorp", ""},
	{"go1.2.3-bigcorp", "1.2.3"},
	{"go1.2.3-bigcorp more text", "1.2.3"},

// described by de and info in directory dir.
// The analysis only uses the name itself; it does not run the program.
func pathVersion(dir string, de fs.DirEntry, info fs.FileInfo) (string, bool) {
	v := gover.FromToolchain(de.Name())
	if v == "" || info.Mode()&0111 == 0 {
		return "", false
	}
	return v, true

func LocalToolchain() string {
	_, t := local()
	return t
}

func local() (goVers, toolVers string) {
	toolVers = runtime.Version()
	if TestVersion != "" {
		toolVers = TestVersion
	}
	goVers = FromToolchain(toolVers)
	if goVers == "" {
		// Development branch. Use "Dev" version with just 1.N, no rc1 or .0 suffix.
		goVers = "1." + strconv.Itoa(goversion.Version)
		toolVers = "go" + goVers
	}
	return goVers, toolVers

// described by de and info in directory dir.
// The analysis only uses the name itself; it does not run the program.
func pathVersion(dir string, de fs.DirEntry, info fs.FileInfo) (string, bool) {
	v := gover.FromToolchain(de.Name())
	if v == "" {
		return "", false
	}

	// Mimicking exec.findExecutable here.
	// ENOSYS means Eaccess is not available or not implemented.
	// EPERM can be returned by Linux containers employing seccomp.

	if r.path == "go" {
		sort.Slice(list, func(i, j int) bool {
			return gover.Compare(list[i], list[j]) < 0
		})
	} else {
		sort.Slice(list, func(i, j int) bool {
			return gover.Compare(gover.FromToolchain(list[i]), gover.FromToolchain(list[j])) < 0
		})
	}
	versions.List = list
	return versions, nil
}

func (r *toolchainRepo) Stat(ctx context.Context, rev string) (*RevInfo, error) {

func pathVersion(dir string, de fs.DirEntry, info fs.FileInfo) (string, bool) {
	pathExts.once.Do(initPathExts)
	name, _, ok := cutExt(de.Name(), pathExts.list)
	if !ok {
		return "", false
	}
	v := gover.FromToolchain(name)
	if v == "" {
		return "", false
	}
	return v, true
}

// cutExt looks for any of the known extensions at the end of file.
// If one is found, cutExt returns the file name with the extension trimmed,

		mode = "auto"
	} else if gotoolchain == "path" {
		mode = "path"
	} else {
		min, suffix, plus := strings.Cut(gotoolchain, "+") // go1.2.3+auto
		if min != "local" {
			v := gover.FromToolchain(min)
			if v == "" {
				if plus {
					base.Fatalf("invalid GOTOOLCHAIN %q: invalid minimum toolchain %q", gotoolchain, min)
				}
				base.Fatalf("invalid GOTOOLCHAIN %q", gotoolchain)
			}

	// TODO(#57001): Add more tests for toolchain lines.
	toolVers := gover.FromToolchain(toolchain)
	if wroteGo && !opts.DropToolchain && !opts.ExplicitToolchain &&
		gover.Compare(goVersion, gover.GoStrictVersion) >= 0 &&
		(gover.Compare(gover.Local(), toolVers) > 0 && !gover.IsLang(gover.Local())) {
		toolchain = "go" + gover.Local()
		toolVers = gover.FromToolchain(toolchain)
	}