github.com/jhump/golang-x-tools@v0.0.0-20220218190644-4958d6d39439/internal/gocommand/vendor.go (about)

     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  	"bytes"
     9  	"context"
    10  	"fmt"
    11  	"os"
    12  	"path/filepath"
    13  	"regexp"
    14  	"strings"
    15  	"time"
    16  
    17  	"golang.org/x/mod/semver"
    18  )
    19  
    20  // ModuleJSON holds information about a module.
    21  type ModuleJSON struct {
    22  	Path      string      // module path
    23  	Version   string      // module version
    24  	Versions  []string    // available module versions (with -versions)
    25  	Replace   *ModuleJSON // replaced by this module
    26  	Time      *time.Time  // time version was created
    27  	Update    *ModuleJSON // available update, if any (with -u)
    28  	Main      bool        // is this the main module?
    29  	Indirect  bool        // is this module only an indirect dependency of main module?
    30  	Dir       string      // directory holding files for this module, if any
    31  	GoMod     string      // path to go.mod file used when loading this module, if any
    32  	GoVersion string      // go version used in module
    33  }
    34  
    35  var modFlagRegexp = regexp.MustCompile(`-mod[ =](\w+)`)
    36  
    37  // VendorEnabled reports whether vendoring is enabled. It takes a *Runner to execute Go commands
    38  // with the supplied context.Context and Invocation. The Invocation can contain pre-defined fields,
    39  // of which only Verb and Args are modified to run the appropriate Go command.
    40  // Inspired by setDefaultBuildMod in modload/init.go
    41  func VendorEnabled(ctx context.Context, inv Invocation, r *Runner) (*ModuleJSON, bool, error) {
    42  	mainMod, go114, err := getMainModuleAnd114(ctx, inv, r)
    43  	if err != nil {
    44  		return nil, false, err
    45  	}
    46  
    47  	// We check the GOFLAGS to see if there is anything overridden or not.
    48  	inv.Verb = "env"
    49  	inv.Args = []string{"GOFLAGS"}
    50  	stdout, err := r.Run(ctx, inv)
    51  	if err != nil {
    52  		return nil, false, err
    53  	}
    54  	goflags := string(bytes.TrimSpace(stdout.Bytes()))
    55  	matches := modFlagRegexp.FindStringSubmatch(goflags)
    56  	var modFlag string
    57  	if len(matches) != 0 {
    58  		modFlag = matches[1]
    59  	}
    60  	if modFlag != "" {
    61  		// Don't override an explicit '-mod=' argument.
    62  		return mainMod, modFlag == "vendor", nil
    63  	}
    64  	if mainMod == nil || !go114 {
    65  		return mainMod, false, nil
    66  	}
    67  	// Check 1.14's automatic vendor mode.
    68  	if fi, err := os.Stat(filepath.Join(mainMod.Dir, "vendor")); err == nil && fi.IsDir() {
    69  		if mainMod.GoVersion != "" && semver.Compare("v"+mainMod.GoVersion, "v1.14") >= 0 {
    70  			// The Go version is at least 1.14, and a vendor directory exists.
    71  			// Set -mod=vendor by default.
    72  			return mainMod, true, nil
    73  		}
    74  	}
    75  	return mainMod, false, nil
    76  }
    77  
    78  // getMainModuleAnd114 gets the main module's information and whether the
    79  // go command in use is 1.14+. This is the information needed to figure out
    80  // if vendoring should be enabled.
    81  func getMainModuleAnd114(ctx context.Context, inv Invocation, r *Runner) (*ModuleJSON, bool, error) {
    82  	const format = `{{.Path}}
    83  {{.Dir}}
    84  {{.GoMod}}
    85  {{.GoVersion}}
    86  {{range context.ReleaseTags}}{{if eq . "go1.14"}}{{.}}{{end}}{{end}}
    87  `
    88  	inv.Verb = "list"
    89  	inv.Args = []string{"-m", "-f", format}
    90  	stdout, err := r.Run(ctx, inv)
    91  	if err != nil {
    92  		return nil, false, err
    93  	}
    94  
    95  	lines := strings.Split(stdout.String(), "\n")
    96  	if len(lines) < 5 {
    97  		return nil, false, fmt.Errorf("unexpected stdout: %q", stdout.String())
    98  	}
    99  	mod := &ModuleJSON{
   100  		Path:      lines[0],
   101  		Dir:       lines[1],
   102  		GoMod:     lines[2],
   103  		GoVersion: lines[3],
   104  		Main:      true,
   105  	}
   106  	return mod, lines[4] == "go1.14", nil
   107  }