Migrate away from templ and towards html/template

3 files changed, 789 insertions, 0 deletions

diff --git a/vendor/golang.org/x/tools/internal/gocommand/invoke.go b/vendor/golang.org/x/tools/internal/gocommand/invoke.go
new file mode 100644
index 0000000..2e59ff8
--- /dev/null
+++ b/vendor/golang.org/x/tools/internal/gocommand/invoke.go
@@ -0,0 +1,555 @@
+// Copyright 2020 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 gocommand is a helper for calling the go command.
+package gocommand
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"reflect"
+	"regexp"
+	"runtime"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"golang.org/x/tools/internal/event"
+	"golang.org/x/tools/internal/event/keys"
+	"golang.org/x/tools/internal/event/label"
+)
+
+// An Runner will run go command invocations and serialize
+// them if it sees a concurrency error.
+type Runner struct {
+	// once guards the runner initialization.
+	once sync.Once
+
+	// inFlight tracks available workers.
+	inFlight chan struct{}
+
+	// serialized guards the ability to run a go command serially,
+	// to avoid deadlocks when claiming workers.
+	serialized chan struct{}
+}
+
+const maxInFlight = 10
+
+func (runner *Runner) initialize() {
+	runner.once.Do(func() {
+		runner.inFlight = make(chan struct{}, maxInFlight)
+		runner.serialized = make(chan struct{}, 1)
+	})
+}
+
+// 1.13: go: updates to go.mod needed, but contents have changed
+// 1.14: go: updating go.mod: existing contents have changed since last read
+var modConcurrencyError = regexp.MustCompile(`go:.*go.mod.*contents have changed`)
+
+// event keys for go command invocations
+var (
+	verb      = keys.NewString("verb", "go command verb")
+	directory = keys.NewString("directory", "")
+)
+
+func invLabels(inv Invocation) []label.Label {
+	return []label.Label{verb.Of(inv.Verb), directory.Of(inv.WorkingDir)}
+}
+
+// Run is a convenience wrapper around RunRaw.
+// It returns only stdout and a "friendly" error.
+func (runner *Runner) Run(ctx context.Context, inv Invocation) (*bytes.Buffer, error) {
+	ctx, done := event.Start(ctx, "gocommand.Runner.Run", invLabels(inv)...)
+	defer done()
+
+	stdout, _, friendly, _ := runner.RunRaw(ctx, inv)
+	return stdout, friendly
+}
+
+// RunPiped runs the invocation serially, always waiting for any concurrent
+// invocations to complete first.
+func (runner *Runner) RunPiped(ctx context.Context, inv Invocation, stdout, stderr io.Writer) error {
+	ctx, done := event.Start(ctx, "gocommand.Runner.RunPiped", invLabels(inv)...)
+	defer done()
+
+	_, err := runner.runPiped(ctx, inv, stdout, stderr)
+	return err
+}
+
+// RunRaw runs the invocation, serializing requests only if they fight over
+// go.mod changes.
+// Postcondition: both error results have same nilness.
+func (runner *Runner) RunRaw(ctx context.Context, inv Invocation) (*bytes.Buffer, *bytes.Buffer, error, error) {
+	ctx, done := event.Start(ctx, "gocommand.Runner.RunRaw", invLabels(inv)...)
+	defer done()
+	// Make sure the runner is always initialized.
+	runner.initialize()
+
+	// First, try to run the go command concurrently.
+	stdout, stderr, friendlyErr, err := runner.runConcurrent(ctx, inv)
+
+	// If we encounter a load concurrency error, we need to retry serially.
+	if friendlyErr != nil && modConcurrencyError.MatchString(friendlyErr.Error()) {
+		event.Error(ctx, "Load concurrency error, will retry serially", err)
+
+		// Run serially by calling runPiped.
+		stdout.Reset()
+		stderr.Reset()
+		friendlyErr, err = runner.runPiped(ctx, inv, stdout, stderr)
+	}
+
+	return stdout, stderr, friendlyErr, err
+}
+
+// Postcondition: both error results have same nilness.
+func (runner *Runner) runConcurrent(ctx context.Context, inv Invocation) (*bytes.Buffer, *bytes.Buffer, error, error) {
+	// Wait for 1 worker to become available.
+	select {
+	case <-ctx.Done():
+		return nil, nil, ctx.Err(), ctx.Err()
+	case runner.inFlight <- struct{}{}:
+		defer func() { <-runner.inFlight }()
+	}
+
+	stdout, stderr := &bytes.Buffer{}, &bytes.Buffer{}
+	friendlyErr, err := inv.runWithFriendlyError(ctx, stdout, stderr)
+	return stdout, stderr, friendlyErr, err
+}
+
+// Postcondition: both error results have same nilness.
+func (runner *Runner) runPiped(ctx context.Context, inv Invocation, stdout, stderr io.Writer) (error, error) {
+	// Make sure the runner is always initialized.
+	runner.initialize()
+
+	// Acquire the serialization lock. This avoids deadlocks between two
+	// runPiped commands.
+	select {
+	case <-ctx.Done():
+		return ctx.Err(), ctx.Err()
+	case runner.serialized <- struct{}{}:
+		defer func() { <-runner.serialized }()
+	}
+
+	// Wait for all in-progress go commands to return before proceeding,
+	// to avoid load concurrency errors.
+	for i := 0; i < maxInFlight; i++ {
+		select {
+		case <-ctx.Done():
+			return ctx.Err(), ctx.Err()
+		case runner.inFlight <- struct{}{}:
+			// Make sure we always "return" any workers we took.
+			defer func() { <-runner.inFlight }()
+		}
+	}
+
+	return inv.runWithFriendlyError(ctx, stdout, stderr)
+}
+
+// An Invocation represents a call to the go command.
+type Invocation struct {
+	Verb       string
+	Args       []string
+	BuildFlags []string
+
+	// If ModFlag is set, the go command is invoked with -mod=ModFlag.
+	// TODO(rfindley): remove, in favor of Args.
+	ModFlag string
+
+	// If ModFile is set, the go command is invoked with -modfile=ModFile.
+	// TODO(rfindley): remove, in favor of Args.
+	ModFile string
+
+	// Overlay is the name of the JSON overlay file that describes
+	// unsaved editor buffers; see [WriteOverlays].
+	// If set, the go command is invoked with -overlay=Overlay.
+	// TODO(rfindley): remove, in favor of Args.
+	Overlay string
+
+	// If CleanEnv is set, the invocation will run only with the environment
+	// in Env, not starting with os.Environ.
+	CleanEnv   bool
+	Env        []string
+	WorkingDir string
+	Logf       func(format string, args ...interface{})
+}
+
+// Postcondition: both error results have same nilness.
+func (i *Invocation) runWithFriendlyError(ctx context.Context, stdout, stderr io.Writer) (friendlyError error, rawError error) {
+	rawError = i.run(ctx, stdout, stderr)
+	if rawError != nil {
+		friendlyError = rawError
+		// Check for 'go' executable not being found.
+		if ee, ok := rawError.(*exec.Error); ok && ee.Err == exec.ErrNotFound {
+			friendlyError = fmt.Errorf("go command required, not found: %v", ee)
+		}
+		if ctx.Err() != nil {
+			friendlyError = ctx.Err()
+		}
+		friendlyError = fmt.Errorf("err: %v: stderr: %s", friendlyError, stderr)
+	}
+	return
+}
+
+// logf logs if i.Logf is non-nil.
+func (i *Invocation) logf(format string, args ...any) {
+	if i.Logf != nil {
+		i.Logf(format, args...)
+	}
+}
+
+func (i *Invocation) run(ctx context.Context, stdout, stderr io.Writer) error {
+	goArgs := []string{i.Verb}
+
+	appendModFile := func() {
+		if i.ModFile != "" {
+			goArgs = append(goArgs, "-modfile="+i.ModFile)
+		}
+	}
+	appendModFlag := func() {
+		if i.ModFlag != "" {
+			goArgs = append(goArgs, "-mod="+i.ModFlag)
+		}
+	}
+	appendOverlayFlag := func() {
+		if i.Overlay != "" {
+			goArgs = append(goArgs, "-overlay="+i.Overlay)
+		}
+	}
+
+	switch i.Verb {
+	case "env", "version":
+		goArgs = append(goArgs, i.Args...)
+	case "mod":
+		// mod needs the sub-verb before flags.
+		goArgs = append(goArgs, i.Args[0])
+		appendModFile()
+		goArgs = append(goArgs, i.Args[1:]...)
+	case "get":
+		goArgs = append(goArgs, i.BuildFlags...)
+		appendModFile()
+		goArgs = append(goArgs, i.Args...)
+
+	default: // notably list and build.
+		goArgs = append(goArgs, i.BuildFlags...)
+		appendModFile()
+		appendModFlag()
+		appendOverlayFlag()
+		goArgs = append(goArgs, i.Args...)
+	}
+	cmd := exec.Command("go", goArgs...)
+	cmd.Stdout = stdout
+	cmd.Stderr = stderr
+
+	// cmd.WaitDelay was added only in go1.20 (see #50436).
+	if waitDelay := reflect.ValueOf(cmd).Elem().FieldByName("WaitDelay"); waitDelay.IsValid() {
+		// https://go.dev/issue/59541: don't wait forever copying stderr
+		// after the command has exited.
+		// After CL 484741 we copy stdout manually, so we we'll stop reading that as
+		// soon as ctx is done. However, we also don't want to wait around forever
+		// for stderr. Give a much-longer-than-reasonable delay and then assume that
+		// something has wedged in the kernel or runtime.
+		waitDelay.Set(reflect.ValueOf(30 * time.Second))
+	}
+
+	// The cwd gets resolved to the real path. On Darwin, where
+	// /tmp is a symlink, this breaks anything that expects the
+	// working directory to keep the original path, including the
+	// go command when dealing with modules.
+	//
+	// os.Getwd has a special feature where if the cwd and the PWD
+	// are the same node then it trusts the PWD, so by setting it
+	// in the env for the child process we fix up all the paths
+	// returned by the go command.
+	if !i.CleanEnv {
+		cmd.Env = os.Environ()
+	}
+	cmd.Env = append(cmd.Env, i.Env...)
+	if i.WorkingDir != "" {
+		cmd.Env = append(cmd.Env, "PWD="+i.WorkingDir)
+		cmd.Dir = i.WorkingDir
+	}
+
+	debugStr := cmdDebugStr(cmd)
+	i.logf("starting %v", debugStr)
+	start := time.Now()
+	defer func() {
+		i.logf("%s for %v", time.Since(start), debugStr)
+	}()
+
+	return runCmdContext(ctx, cmd)
+}
+
+// DebugHangingGoCommands may be set by tests to enable additional
+// instrumentation (including panics) for debugging hanging Go commands.
+//
+// See golang/go#54461 for details.
+var DebugHangingGoCommands = false
+
+// runCmdContext is like exec.CommandContext except it sends os.Interrupt
+// before os.Kill.
+func runCmdContext(ctx context.Context, cmd *exec.Cmd) (err error) {
+	// If cmd.Stdout is not an *os.File, the exec package will create a pipe and
+	// copy it to the Writer in a goroutine until the process has finished and
+	// either the pipe reaches EOF or command's WaitDelay expires.
+	//
+	// However, the output from 'go list' can be quite large, and we don't want to
+	// keep reading (and allocating buffers) if we've already decided we don't
+	// care about the output. We don't want to wait for the process to finish, and
+	// we don't wait to wait for the WaitDelay to expire either.
+	//
+	// Instead, if cmd.Stdout requires a copying goroutine we explicitly replace
+	// it with a pipe (which is an *os.File), which we can close in order to stop
+	// copying output as soon as we realize we don't care about it.
+	var stdoutW *os.File
+	if cmd.Stdout != nil {
+		if _, ok := cmd.Stdout.(*os.File); !ok {
+			var stdoutR *os.File
+			stdoutR, stdoutW, err = os.Pipe()
+			if err != nil {
+				return err
+			}
+			prevStdout := cmd.Stdout
+			cmd.Stdout = stdoutW
+
+			stdoutErr := make(chan error, 1)
+			go func() {
+				_, err := io.Copy(prevStdout, stdoutR)
+				if err != nil {
+					err = fmt.Errorf("copying stdout: %w", err)
+				}
+				stdoutErr <- err
+			}()
+			defer func() {
+				// We started a goroutine to copy a stdout pipe.
+				// Wait for it to finish, or terminate it if need be.
+				var err2 error
+				select {
+				case err2 = <-stdoutErr:
+					stdoutR.Close()
+				case <-ctx.Done():
+					stdoutR.Close()
+					// Per https://pkg.go.dev/os#File.Close, the call to stdoutR.Close
+					// should cause the Read call in io.Copy to unblock and return
+					// immediately, but we still need to receive from stdoutErr to confirm
+					// that it has happened.
+					<-stdoutErr
+					err2 = ctx.Err()
+				}
+				if err == nil {
+					err = err2
+				}
+			}()
+
+			// Per https://pkg.go.dev/os/exec#Cmd, “If Stdout and Stderr are the
+			// same writer, and have a type that can be compared with ==, at most
+			// one goroutine at a time will call Write.”
+			//
+			// Since we're starting a goroutine that writes to cmd.Stdout, we must
+			// also update cmd.Stderr so that it still holds.
+			func() {
+				defer func() { recover() }()
+				if cmd.Stderr == prevStdout {
+					cmd.Stderr = cmd.Stdout
+				}
+			}()
+		}
+	}
+
+	startTime := time.Now()
+	err = cmd.Start()
+	if stdoutW != nil {
+		// The child process has inherited the pipe file,
+		// so close the copy held in this process.
+		stdoutW.Close()
+		stdoutW = nil
+	}
+	if err != nil {
+		return err
+	}
+
+	resChan := make(chan error, 1)
+	go func() {
+		resChan <- cmd.Wait()
+	}()
+
+	// If we're interested in debugging hanging Go commands, stop waiting after a
+	// minute and panic with interesting information.
+	debug := DebugHangingGoCommands
+	if debug {
+		timer := time.NewTimer(1 * time.Minute)
+		defer timer.Stop()
+		select {
+		case err := <-resChan:
+			return err
+		case <-timer.C:
+			HandleHangingGoCommand(startTime, cmd)
+		case <-ctx.Done():
+		}
+	} else {
+		select {
+		case err := <-resChan:
+			return err
+		case <-ctx.Done():
+		}
+	}
+
+	// Cancelled. Interrupt and see if it ends voluntarily.
+	if err := cmd.Process.Signal(os.Interrupt); err == nil {
+		// (We used to wait only 1s but this proved
+		// fragile on loaded builder machines.)
+		timer := time.NewTimer(5 * time.Second)
+		defer timer.Stop()
+		select {
+		case err := <-resChan:
+			return err
+		case <-timer.C:
+		}
+	}
+
+	// Didn't shut down in response to interrupt. Kill it hard.
+	// TODO(rfindley): per advice from bcmills@, it may be better to send SIGQUIT
+	// on certain platforms, such as unix.
+	if err := cmd.Process.Kill(); err != nil && !errors.Is(err, os.ErrProcessDone) && debug {
+		log.Printf("error killing the Go command: %v", err)
+	}
+
+	return <-resChan
+}
+
+func HandleHangingGoCommand(start time.Time, cmd *exec.Cmd) {
+	switch runtime.GOOS {
+	case "linux", "darwin", "freebsd", "netbsd":
+		fmt.Fprintln(os.Stderr, `DETECTED A HANGING GO COMMAND
+
+The gopls test runner has detected a hanging go command. In order to debug
+this, the output of ps and lsof/fstat is printed below.
+
+See golang/go#54461 for more details.`)
+
+		fmt.Fprintln(os.Stderr, "\nps axo ppid,pid,command:")
+		fmt.Fprintln(os.Stderr, "-------------------------")
+		psCmd := exec.Command("ps", "axo", "ppid,pid,command")
+		psCmd.Stdout = os.Stderr
+		psCmd.Stderr = os.Stderr
+		if err := psCmd.Run(); err != nil {
+			panic(fmt.Sprintf("running ps: %v", err))
+		}
+
+		listFiles := "lsof"
+		if runtime.GOOS == "freebsd" || runtime.GOOS == "netbsd" {
+			listFiles = "fstat"
+		}
+
+		fmt.Fprintln(os.Stderr, "\n"+listFiles+":")
+		fmt.Fprintln(os.Stderr, "-----")
+		listFilesCmd := exec.Command(listFiles)
+		listFilesCmd.Stdout = os.Stderr
+		listFilesCmd.Stderr = os.Stderr
+		if err := listFilesCmd.Run(); err != nil {
+			panic(fmt.Sprintf("running %s: %v", listFiles, err))
+		}
+	}
+	panic(fmt.Sprintf("detected hanging go command (golang/go#54461); waited %s\n\tcommand:%s\n\tpid:%d", time.Since(start), cmd, cmd.Process.Pid))
+}
+
+func cmdDebugStr(cmd *exec.Cmd) string {
+	env := make(map[string]string)
+	for _, kv := range cmd.Env {
+		split := strings.SplitN(kv, "=", 2)
+		if len(split) == 2 {
+			k, v := split[0], split[1]
+			env[k] = v
+		}
+	}
+
+	var args []string
+	for _, arg := range cmd.Args {
+		quoted := strconv.Quote(arg)
+		if quoted[1:len(quoted)-1] != arg || strings.Contains(arg, " ") {
+			args = append(args, quoted)
+		} else {
+			args = append(args, arg)
+		}
+	}
+	return fmt.Sprintf("GOROOT=%v GOPATH=%v GO111MODULE=%v GOPROXY=%v PWD=%v %v", env["GOROOT"], env["GOPATH"], env["GO111MODULE"], env["GOPROXY"], env["PWD"], strings.Join(args, " "))
+}
+
+// WriteOverlays writes each value in the overlay (see the Overlay
+// field of go/packages.Config) to a temporary file and returns the name
+// of a JSON file describing the mapping that is suitable for the "go
+// list -overlay" flag.
+//
+// On success, the caller must call the cleanup function exactly once
+// when the files are no longer needed.
+func WriteOverlays(overlay map[string][]byte) (filename string, cleanup func(), err error) {
+	// Do nothing if there are no overlays in the config.
+	if len(overlay) == 0 {
+		return "", func() {}, nil
+	}
+
+	dir, err := os.MkdirTemp("", "gocommand-*")
+	if err != nil {
+		return "", nil, err
+	}
+
+	// The caller must clean up this directory,
+	// unless this function returns an error.
+	// (The cleanup operand of each return
+	// statement below is ignored.)
+	defer func() {
+		cleanup = func() {
+			os.RemoveAll(dir)
+		}
+		if err != nil {
+			cleanup()
+			cleanup = nil
+		}
+	}()
+
+	// Write each map entry to a temporary file.
+	overlays := make(map[string]string)
+	for k, v := range overlay {
+		// Use a unique basename for each file (001-foo.go),
+		// to avoid creating nested directories.
+		base := fmt.Sprintf("%d-%s", 1+len(overlays), filepath.Base(k))
+		filename := filepath.Join(dir, base)
+		err := os.WriteFile(filename, v, 0666)
+		if err != nil {
+			return "", nil, err
+		}
+		overlays[k] = filename
+	}
+
+	// Write the JSON overlay file that maps logical file names to temp files.
+	//
+	// OverlayJSON is the format overlay files are expected to be in.
+	// The Replace map maps from overlaid paths to replacement paths:
+	// the Go command will forward all reads trying to open
+	// each overlaid path to its replacement path, or consider the overlaid
+	// path not to exist if the replacement path is empty.
+	//
+	// From golang/go#39958.
+	type OverlayJSON struct {
+		Replace map[string]string `json:"replace,omitempty"`
+	}
+	b, err := json.Marshal(OverlayJSON{Replace: overlays})
+	if err != nil {
+		return "", nil, err
+	}
+	filename = filepath.Join(dir, "overlay.json")
+	if err := os.WriteFile(filename, b, 0666); err != nil {
+		return "", nil, err
+	}
+
+	return filename, nil, nil
+}
diff --git a/vendor/golang.org/x/tools/internal/gocommand/vendor.go b/vendor/golang.org/x/tools/internal/gocommand/vendor.go
new file mode 100644
index 0000000..e38d1fb
--- /dev/null
+++ b/vendor/golang.org/x/tools/internal/gocommand/vendor.go
@@ -0,0 +1,163 @@
+// Copyright 2020 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 gocommand
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+	"time"
+
+	"golang.org/x/mod/semver"
+)
+
+// ModuleJSON holds information about a module.
+type ModuleJSON struct {
+	Path      string      // module path
+	Version   string      // module version
+	Versions  []string    // available module versions (with -versions)
+	Replace   *ModuleJSON // replaced by this module
+	Time      *time.Time  // time version was created
+	Update    *ModuleJSON // available update, if any (with -u)
+	Main      bool        // is this the main module?
+	Indirect  bool        // is this module only an indirect dependency of main module?
+	Dir       string      // directory holding files for this module, if any
+	GoMod     string      // path to go.mod file used when loading this module, if any
+	GoVersion string      // go version used in module
+}
+
+var modFlagRegexp = regexp.MustCompile(`-mod[ =](\w+)`)
+
+// VendorEnabled reports whether vendoring is enabled. It takes a *Runner to execute Go commands
+// with the supplied context.Context and Invocation. The Invocation can contain pre-defined fields,
+// of which only Verb and Args are modified to run the appropriate Go command.
+// Inspired by setDefaultBuildMod in modload/init.go
+func VendorEnabled(ctx context.Context, inv Invocation, r *Runner) (bool, *ModuleJSON, error) {
+	mainMod, go114, err := getMainModuleAnd114(ctx, inv, r)
+	if err != nil {
+		return false, nil, err
+	}
+
+	// We check the GOFLAGS to see if there is anything overridden or not.
+	inv.Verb = "env"
+	inv.Args = []string{"GOFLAGS"}
+	stdout, err := r.Run(ctx, inv)
+	if err != nil {
+		return false, nil, err
+	}
+	goflags := string(bytes.TrimSpace(stdout.Bytes()))
+	matches := modFlagRegexp.FindStringSubmatch(goflags)
+	var modFlag string
+	if len(matches) != 0 {
+		modFlag = matches[1]
+	}
+	// Don't override an explicit '-mod=' argument.
+	if modFlag == "vendor" {
+		return true, mainMod, nil
+	} else if modFlag != "" {
+		return false, nil, nil
+	}
+	if mainMod == nil || !go114 {
+		return false, nil, nil
+	}
+	// Check 1.14's automatic vendor mode.
+	if fi, err := os.Stat(filepath.Join(mainMod.Dir, "vendor")); err == nil && fi.IsDir() {
+		if mainMod.GoVersion != "" && semver.Compare("v"+mainMod.GoVersion, "v1.14") >= 0 {
+			// The Go version is at least 1.14, and a vendor directory exists.
+			// Set -mod=vendor by default.
+			return true, mainMod, nil
+		}
+	}
+	return false, nil, nil
+}
+
+// getMainModuleAnd114 gets one of the main modules' information and whether the
+// go command in use is 1.14+. This is the information needed to figure out
+// if vendoring should be enabled.
+func getMainModuleAnd114(ctx context.Context, inv Invocation, r *Runner) (*ModuleJSON, bool, error) {
+	const format = `{{.Path}}
+{{.Dir}}
+{{.GoMod}}
+{{.GoVersion}}
+{{range context.ReleaseTags}}{{if eq . "go1.14"}}{{.}}{{end}}{{end}}
+`
+	inv.Verb = "list"
+	inv.Args = []string{"-m", "-f", format}
+	stdout, err := r.Run(ctx, inv)
+	if err != nil {
+		return nil, false, err
+	}
+
+	lines := strings.Split(stdout.String(), "\n")
+	if len(lines) < 5 {
+		return nil, false, fmt.Errorf("unexpected stdout: %q", stdout.String())
+	}
+	mod := &ModuleJSON{
+		Path:      lines[0],
+		Dir:       lines[1],
+		GoMod:     lines[2],
+		GoVersion: lines[3],
+		Main:      true,
+	}
+	return mod, lines[4] == "go1.14", nil
+}
+
+// WorkspaceVendorEnabled reports whether workspace vendoring is enabled. It takes a *Runner to execute Go commands
+// with the supplied context.Context and Invocation. The Invocation can contain pre-defined fields,
+// of which only Verb and Args are modified to run the appropriate Go command.
+// Inspired by setDefaultBuildMod in modload/init.go
+func WorkspaceVendorEnabled(ctx context.Context, inv Invocation, r *Runner) (bool, []*ModuleJSON, error) {
+	inv.Verb = "env"
+	inv.Args = []string{"GOWORK"}
+	stdout, err := r.Run(ctx, inv)
+	if err != nil {
+		return false, nil, err
+	}
+	goWork := string(bytes.TrimSpace(stdout.Bytes()))
+	if fi, err := os.Stat(filepath.Join(filepath.Dir(goWork), "vendor")); err == nil && fi.IsDir() {
+		mainMods, err := getWorkspaceMainModules(ctx, inv, r)
+		if err != nil {
+			return false, nil, err
+		}
+		return true, mainMods, nil
+	}
+	return false, nil, nil
+}
+
+// getWorkspaceMainModules gets the main modules' information.
+// This is the information needed to figure out if vendoring should be enabled.
+func getWorkspaceMainModules(ctx context.Context, inv Invocation, r *Runner) ([]*ModuleJSON, error) {
+	const format = `{{.Path}}
+{{.Dir}}
+{{.GoMod}}
+{{.GoVersion}}
+`
+	inv.Verb = "list"
+	inv.Args = []string{"-m", "-f", format}
+	stdout, err := r.Run(ctx, inv)
+	if err != nil {
+		return nil, err
+	}
+
+	lines := strings.Split(strings.TrimSuffix(stdout.String(), "\n"), "\n")
+	if len(lines) < 4 {
+		return nil, fmt.Errorf("unexpected stdout: %q", stdout.String())
+	}
+	mods := make([]*ModuleJSON, 0, len(lines)/4)
+	for i := 0; i < len(lines); i += 4 {
+		mods = append(mods, &ModuleJSON{
+			Path:      lines[i],
+			Dir:       lines[i+1],
+			GoMod:     lines[i+2],
+			GoVersion: lines[i+3],
+			Main:      true,
+		})
+	}
+	return mods, nil
+}
diff --git a/vendor/golang.org/x/tools/internal/gocommand/version.go b/vendor/golang.org/x/tools/internal/gocommand/version.go
new file mode 100644
index 0000000..446c584
--- /dev/null
+++ b/vendor/golang.org/x/tools/internal/gocommand/version.go
@@ -0,0 +1,71 @@
+// Copyright 2020 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 gocommand
+
+import (
+	"context"
+	"fmt"
+	"regexp"
+	"strings"
+)
+
+// GoVersion reports the minor version number of the highest release
+// tag built into the go command on the PATH.
+//
+// Note that this may be higher than the version of the go tool used
+// to build this application, and thus the versions of the standard
+// go/{scanner,parser,ast,types} packages that are linked into it.
+// In that case, callers should either downgrade to the version of
+// go used to build the application, or report an error that the
+// application is too old to use the go command on the PATH.
+func GoVersion(ctx context.Context, inv Invocation, r *Runner) (int, error) {
+	inv.Verb = "list"
+	inv.Args = []string{"-e", "-f", `{{context.ReleaseTags}}`, `--`, `unsafe`}
+	inv.BuildFlags = nil // This is not a build command.
+	inv.ModFlag = ""
+	inv.ModFile = ""
+	inv.Env = append(inv.Env[:len(inv.Env):len(inv.Env)], "GO111MODULE=off")
+
+	stdoutBytes, err := r.Run(ctx, inv)
+	if err != nil {
+		return 0, err
+	}
+	stdout := stdoutBytes.String()
+	if len(stdout) < 3 {
+		return 0, fmt.Errorf("bad ReleaseTags output: %q", stdout)
+	}
+	// Split up "[go1.1 go1.15]" and return highest go1.X value.
+	tags := strings.Fields(stdout[1 : len(stdout)-2])
+	for i := len(tags) - 1; i >= 0; i-- {
+		var version int
+		if _, err := fmt.Sscanf(tags[i], "go1.%d", &version); err != nil {
+			continue
+		}
+		return version, nil
+	}
+	return 0, fmt.Errorf("no parseable ReleaseTags in %v", tags)
+}
+
+// GoVersionOutput returns the complete output of the go version command.
+func GoVersionOutput(ctx context.Context, inv Invocation, r *Runner) (string, error) {
+	inv.Verb = "version"
+	goVersion, err := r.Run(ctx, inv)
+	if err != nil {
+		return "", err
+	}
+	return goVersion.String(), nil
+}
+
+// ParseGoVersionOutput extracts the Go version string
+// from the output of the "go version" command.
+// Given an unrecognized form, it returns an empty string.
+func ParseGoVersionOutput(data string) string {
+	re := regexp.MustCompile(`^go version (go\S+|devel \S+)`)
+	m := re.FindStringSubmatch(data)
+	if len(m) != 2 {
+		return "" // unrecognized version
+	}
+	return m[1]
+}