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// 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 gover
import (
"cmd/go/internal/base"
"context"
"errors"
"fmt"
"strings"
)
// FromToolchain returns the Go version for the named toolchain,
// derived from the name itself (not by running the toolchain).
// A toolchain is named "goVERSION".
// A suffix after the VERSION introduced by a -, space, or tab is removed.
// Examples:
//
// FromToolchain("go1.2.3") == "1.2.3"
// FromToolchain("go1.2.3-bigcorp") == "1.2.3"
// FromToolchain("invalid") == ""
func FromToolchain(name string) string {
if strings.ContainsAny(name, "\\/") {
// The suffix must not include a path separator, since that would cause
// exec.LookPath to resolve it from a relative directory instead of from
// $PATH.
return ""
}
var v string
if strings.HasPrefix(name, "go") {
v = name[2:]
} else {
return ""
}
// Some builds use custom suffixes; strip them.
if i := strings.IndexAny(v, " \t-"); i >= 0 {
v = v[:i]
}
if !IsValid(v) {
return ""
}
return v
}
func maybeToolchainVersion(name string) string {
if IsValid(name) {
return name
}
return FromToolchain(name)
}
// Startup records the information that went into the startup-time version switch.
// It is initialized by switchGoToolchain.
var Startup struct {
GOTOOLCHAIN string // $GOTOOLCHAIN setting
AutoFile string // go.mod or go.work file consulted
AutoGoVersion string // go line found in file
AutoToolchain string // toolchain line found in file
}
// A TooNewError explains that a module is too new for this version of Go.
type TooNewError struct {
What string
GoVersion string
Toolchain string // for callers if they want to use it, but not printed
}
func (e *TooNewError) Error() string {
var explain string
if Startup.GOTOOLCHAIN != "" && Startup.GOTOOLCHAIN != "auto" {
explain = "; GOTOOLCHAIN=" + Startup.GOTOOLCHAIN
}
if Startup.AutoFile != "" && (Startup.AutoGoVersion != "" || Startup.AutoToolchain != "") {
explain += fmt.Sprintf("; %s sets ", base.ShortPath(Startup.AutoFile))
if Startup.AutoToolchain != "" {
explain += "toolchain " + Startup.AutoToolchain
} else {
explain += "go " + Startup.AutoGoVersion
}
}
return fmt.Sprintf("%v requires go >= %v (running go %v%v)", e.What, e.GoVersion, Local(), explain)
}
var ErrTooNew = errors.New("module too new")
func (e *TooNewError) Is(err error) bool {
return err == ErrTooNew
}
// A Switcher provides the ability to switch to a new toolchain in response to TooNewErrors.
// See [cmd/go/internal/toolchain.Switcher] for documentation.
type Switcher interface {
Error(err error)
Switch(ctx context.Context)
}