version.go

Documentation: golang.org/x/tools/internal/gocommand

     1  // Copyright 2020 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 gocommand
     6  
     7  import (
     8  	"context"
     9  	"fmt"
    10  	"regexp"
    11  	"strings"
    12  )
    13  
    14  // GoVersion reports the minor version number of the highest release
    15  // tag built into the go command on the PATH.
    16  //
    17  // Note that this may be higher than the version of the go tool used
    18  // to build this application, and thus the versions of the standard
    19  // go/{scanner,parser,ast,types} packages that are linked into it.
    20  // In that case, callers should either downgrade to the version of
    21  // go used to build the application, or report an error that the
    22  // application is too old to use the go command on the PATH.
    23  func GoVersion(ctx context.Context, inv Invocation, r *Runner) (int, error) {
    24  	inv.Verb = "list"
    25  	inv.Args = []string{"-e", "-f", `{{context.ReleaseTags}}`, `--`, `unsafe`}
    26  	inv.BuildFlags = nil // This is not a build command.
    27  	inv.ModFlag = ""
    28  	inv.ModFile = ""
    29  	inv.Env = append(inv.Env[:len(inv.Env):len(inv.Env)], "GO111MODULE=off")
    30  
    31  	stdoutBytes, err := r.Run(ctx, inv)
    32  	if err != nil {
    33  		return 0, err
    34  	}
    35  	stdout := stdoutBytes.String()
    36  	if len(stdout) < 3 {
    37  		return 0, fmt.Errorf("bad ReleaseTags output: %q", stdout)
    38  	}
    39  	// Split up "[go1.1 go1.15]" and return highest go1.X value.
    40  	tags := strings.Fields(stdout[1 : len(stdout)-2])
    41  	for i := len(tags) - 1; i >= 0; i-- {
    42  		var version int
    43  		if _, err := fmt.Sscanf(tags[i], "go1.%d", &version); err != nil {
    44  			continue
    45  		}
    46  		return version, nil
    47  	}
    48  	return 0, fmt.Errorf("no parseable ReleaseTags in %v", tags)
    49  }
    50  
    51  // GoVersionOutput returns the complete output of the go version command.
    52  func GoVersionOutput(ctx context.Context, inv Invocation, r *Runner) (string, error) {
    53  	inv.Verb = "version"
    54  	goVersion, err := r.Run(ctx, inv)
    55  	if err != nil {
    56  		return "", err
    57  	}
    58  	return goVersion.String(), nil
    59  }
    60  
    61  // ParseGoVersionOutput extracts the Go version string
    62  // from the output of the "go version" command.
    63  // Given an unrecognized form, it returns an empty string.
    64  func ParseGoVersionOutput(data string) string {
    65  	re := regexp.MustCompile(`^go version (go\S+|devel \S+)`)
    66  	m := re.FindStringSubmatch(data)
    67  	if len(m) != 2 {
    68  		return "" // unrecognized version
    69  	}
    70  	return m[1]
    71  }
    72
View as plain text