gover.go

     1  // Copyright 2023 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Package gover implements support for Go toolchain versions like 1.21.0 and 1.21rc1.
     6  // (For historical reasons, Go does not use semver for its toolchains.)
     7  // This package provides the same basic analysis that golang.org/x/mod/semver does for semver.
     8  // It also provides some helpers for extracting versions from go.mod files
     9  // and for dealing with module.Versions that may use Go versions or semver
    10  // depending on the module path.
    11  package gover
    12  
    13  import (
    14  	"internal/gover"
    15  )
    16  
    17  // Compare returns -1, 0, or +1 depending on whether
    18  // x < y, x == y, or x > y, interpreted as toolchain versions.
    19  // The versions x and y must not begin with a "go" prefix: just "1.21" not "go1.21".
    20  // Malformed versions compare less than well-formed versions and equal to each other.
    21  // The language version "1.21" compares less than the release candidate and eventual releases "1.21rc1" and "1.21.0".
    22  func Compare(x, y string) int {
    23  	return gover.Compare(x, y)
    24  }
    25  
    26  // Max returns the maximum of x and y interpreted as toolchain versions,
    27  // compared using Compare.
    28  // If x and y compare equal, Max returns x.
    29  func Max(x, y string) string {
    30  	return gover.Max(x, y)
    31  }
    32  
    33  // IsLang reports whether v denotes the overall Go language version
    34  // and not a specific release. Starting with the Go 1.21 release, "1.x" denotes
    35  // the overall language version; the first release is "1.x.0".
    36  // The distinction is important because the relative ordering is
    37  //
    38  //	1.21 < 1.21rc1 < 1.21.0
    39  //
    40  // meaning that Go 1.21rc1 and Go 1.21.0 will both handle go.mod files that
    41  // say "go 1.21", but Go 1.21rc1 will not handle files that say "go 1.21.0".
    42  func IsLang(x string) bool {
    43  	return gover.IsLang(x)
    44  }
    45  
    46  // Lang returns the Go language version. For example, Lang("1.2.3") == "1.2".
    47  func Lang(x string) string {
    48  	return gover.Lang(x)
    49  }
    50  
    51  // IsPrerelease reports whether v denotes a Go prerelease version.
    52  func IsPrerelease(x string) bool {
    53  	return gover.Parse(x).Kind != ""
    54  }
    55  
    56  // Prev returns the Go major release immediately preceding v,
    57  // or v itself if v is the first Go major release (1.0) or not a supported
    58  // Go version.
    59  //
    60  // Examples:
    61  //
    62  //	Prev("1.2") = "1.1"
    63  //	Prev("1.3rc4") = "1.2"
    64  func Prev(x string) string {
    65  	v := gover.Parse(x)
    66  	if gover.CmpInt(v.Minor, "1") <= 0 {
    67  		return v.Major
    68  	}
    69  	return v.Major + "." + gover.DecInt(v.Minor)
    70  }
    71  
    72  // IsValid reports whether the version x is valid.
    73  func IsValid(x string) bool {
    74  	return gover.IsValid(x)
    75  }
    76
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