src

versions.go (2030B)

---

 // Copyright 2023 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 package versions
 
 import (
 	"strings"
 )
 
 // Note: If we use build tags to use go/versions when go >=1.22,
 // we run into go.dev/issue/53737. Under some operations users would see an
 // import of "go/versions" even if they would not compile the file.
 // For example, during `go get -u ./...` (go.dev/issue/64490) we do not try to include
 // For this reason, this library just a clone of go/versions for the moment.
 
 // Lang returns the Go language version for version x.
 // If x is not a valid version, Lang returns the empty string.
 // For example:
 //
 //	Lang("go1.21rc2") = "go1.21"
 //	Lang("go1.21.2") = "go1.21"
 //	Lang("go1.21") = "go1.21"
 //	Lang("go1") = "go1"
 //	Lang("bad") = ""
 //	Lang("1.21") = ""
 func Lang(x string) string {
 	v := lang(stripGo(x))
 	if v == "" {
 		return ""
 	}
 	return x[:2+len(v)] // "go"+v without allocation
 }
 
 // Compare returns -1, 0, or +1 depending on whether
 // x < y, x == y, or x > y, interpreted as Go versions.
 // The versions x and y must begin with a "go" prefix: "go1.21" not "1.21".
 // Invalid versions, including the empty string, compare less than
 // valid versions and equal to each other.
 // The language version "go1.21" compares less than the
 // release candidate and eventual releases "go1.21rc1" and "go1.21.0".
 // Custom toolchain suffixes are ignored during comparison:
 // "go1.21.0" and "go1.21.0-bigcorp" are equal.
 func Compare(x, y string) int { return compare(stripGo(x), stripGo(y)) }
 
 // IsValid reports whether the version x is valid.
 func IsValid(x string) bool { return isValid(stripGo(x)) }
 
 // stripGo converts from a "go1.21" version to a "1.21" version.
 // If v does not start with "go", stripGo returns the empty string (a known invalid version).
 func stripGo(v string) string {
 	v, _, _ = strings.Cut(v, "-") // strip -bigcorp suffix.
 	if len(v) < 2 || v[:2] != "go" {
 		return ""
 	}
 	return v[2:]
 }