func getWizard(dep *cfg.Dependency) {
	var remote string
	if dep.Repository != "" {
		remote = dep.Repository
	} else {
		remote = "https://" + dep.Name
	}

	// Lookup dependency info and store in cache.
	msg.Info("--> Gathering release information for %s", dep.Name)
	wizardFindVersions(dep)

	memlatest := cache.MemLatest(remote)
	if memlatest != "" {
		dres := wizardAskLatest(memlatest, dep)
		if dres {
			dep.Reference = memlatest

			sv, err := semver.NewVersion(dep.Reference)
			if err == nil {
				res := wizardAskRange(sv, dep)
				if res == "m" {
					dep.Reference = "^" + sv.String()
				} else if res == "p" {
					dep.Reference = "~" + sv.String()
				}
			}
		}
	}
}

// VcsExists checks if the directory has a local VCS checkout.
func VcsExists(dep *cfg.Dependency, dest string) bool {
	repo, err := dep.GetRepo(dest)
	if err != nil {
		return false
	}

	return repo.CheckLocal()
}

// VcsLastCommit gets the last commit ID from the given dependency.
func VcsLastCommit(dep *cfg.Dependency, vend string) (string, error) {
	cwd := filepath.Join(vend, filepath.FromSlash(dep.Name))
	repo, err := dep.GetRepo(cwd)
	if err != nil {
		return "", err
	}

	if repo.CheckLocal() == false {
		return "", fmt.Errorf("%s is not a VCS repo\n", dep.Name)
	}

	version, err := repo.Version()
	if err != nil {
		return "", err
	}

	return version, nil
}

// VcsGet figures out how to fetch a dependency, and then gets it.
//
// VcsGet installs into the cache.
func VcsGet(dep *cfg.Dependency) error {

	key, err := cp.Key(dep.Remote())
	if err != nil {
		msg.Die("Cache key generation error: %s", err)
	}
	location := cp.Location()
	d := filepath.Join(location, "src", key)

	repo, err := dep.GetRepo(d)
	if err != nil {
		return err
	}
	// If the directory does not exist this is a first cache.
	if _, err = os.Stat(d); os.IsNotExist(err) {
		msg.Debug("Adding %s to the cache for the first time", dep.Name)
		err = repo.Get()
		if err != nil {
			return err
		}
		branch := findCurrentBranch(repo)
		if branch != "" {
			msg.Debug("Saving default branch for %s", repo.Remote())
			c := cp.RepoInfo{DefaultBranch: branch}
			err = cp.SaveRepoData(key, c)
			if err == cp.ErrCacheDisabled {
				msg.Debug("Unable to cache default branch because caching is disabled")
			} else if err != nil {
				msg.Debug("Error saving %s to cache. Error: %s", repo.Remote(), err)
			}
		}
	} else {
		msg.Debug("Updating %s in the cache", dep.Name)
		err = repo.Update()
		if err != nil {
			return err
		}
	}

	return nil
}

func TestAddPkgsToConfig(t *testing.T) {
	// Route output to discard so it's not displayed with the test output.
	o := msg.Default.Stderr
	msg.Default.Stderr = ioutil.Discard

	conf := new(cfg.Config)
	dep := new(cfg.Dependency)
	dep.Name = "github.com/Masterminds/cookoo"
	dep.Subpackages = append(dep.Subpackages, "convert")
	conf.Imports = append(conf.Imports, dep)

	names := []string{
		"github.com/Masterminds/cookoo/fmt",
		"github.com/Masterminds/semver",
	}

	addPkgsToConfig(conf, names, false, true)

	if !conf.HasDependency("github.com/Masterminds/semver") {
		t.Error("addPkgsToConfig failed to add github.com/Masterminds/semver")
	}

	d := conf.Imports.Get("github.com/Masterminds/cookoo")
	found := false
	for _, s := range d.Subpackages {
		if s == "fmt" {
			found = true
		}
	}
	if !found {
		t.Error("addPkgsToConfig failed to add subpackage to existing import")
	}

	// Restore messaging to original location
	msg.Default.Stderr = o
}

func determineDependency(v, dep *cfg.Dependency, dest string) *cfg.Dependency {
	repo, err := v.GetRepo(dest)
	if err != nil {
		singleWarn("Unable to access repo for %s\n", v.Name)
		singleInfo("Keeping %s %s", v.Name, v.Reference)
		return v
	}

	vIsRef := repo.IsReference(v.Reference)
	depIsRef := repo.IsReference(dep.Reference)

	// Both are references and they are different ones.
	if vIsRef && depIsRef {
		singleWarn("Conflict: %s ref is %s, but also asked for %s\n", v.Name, v.Reference, dep.Reference)
		singleInfo("Keeping %s %s", v.Name, v.Reference)
		return v
	} else if vIsRef {
		// The current one is a reference and the suggestion is a SemVer constraint.
		con, err := semver.NewConstraint(dep.Reference)
		if err != nil {
			singleWarn("Version issue for %s: '%s' is neither a reference or semantic version constraint\n", dep.Name, dep.Reference)
			singleInfo("Keeping %s %s", v.Name, v.Reference)
			return v
		}

		ver, err := semver.NewVersion(v.Reference)
		if err != nil {
			// The existing version is not a semantic version.
			singleWarn("Conflict: %s version is %s, but also asked for %s\n", v.Name, v.Reference, dep.Reference)
			singleInfo("Keeping %s %s", v.Name, v.Reference)
			return v
		}

		if con.Check(ver) {
			singleInfo("Keeping %s %s because it fits constraint '%s'", v.Name, v.Reference, dep.Reference)
			return v
		}
		singleWarn("Conflict: %s version is %s but does not meet constraint '%s'\n", v.Name, v.Reference, dep.Reference)
		singleInfo("Keeping %s %s", v.Name, v.Reference)
		return v
	} else if depIsRef {

		con, err := semver.NewConstraint(v.Reference)
		if err != nil {
			singleWarn("Version issue for %s: '%s' is neither a reference or semantic version constraint\n", v.Name, v.Reference)
			singleInfo("Keeping %s %s", v.Name, v.Reference)
			return v
		}

		ver, err := semver.NewVersion(dep.Reference)
		if err != nil {
			singleWarn("Conflict: %s version is %s, but also asked for %s\n", v.Name, v.Reference, dep.Reference)
			singleInfo("Keeping %s %s", v.Name, v.Reference)
			return v
		}

		if con.Check(ver) {
			v.Reference = dep.Reference
			singleInfo("Using %s %s because it fits constraint '%s'", v.Name, v.Reference, v.Reference)
			return v
		}
		singleWarn("Conflict: %s semantic version constraint is %s but '%s' does not meet the constraint\n", v.Name, v.Reference, v.Reference)
		singleInfo("Keeping %s %s", v.Name, v.Reference)
		return v
	}
	// Neither is a vcs reference and both could be semantic version
	// constraints that are different.

	_, err = semver.NewConstraint(dep.Reference)
	if err != nil {
		// dd.Reference is not a reference or a valid constraint.
		singleWarn("Version %s %s is not a reference or valid semantic version constraint\n", dep.Name, dep.Reference)
		singleInfo("Keeping %s %s", v.Name, v.Reference)
		return v
	}

	_, err = semver.NewConstraint(v.Reference)
	if err != nil {
		// existing.Reference is not a reference or a valid constraint.
		// We really should never end up here.
		singleWarn("Version %s %s is not a reference or valid semantic version constraint\n", v.Name, v.Reference)

		v.Reference = dep.Reference
		v.Pin = ""
		singleInfo("Using %s %s because it is a valid version", v.Name, v.Reference)
		return v
	}

	// Both versions are constraints. Try to merge them.
	// If either comparison has an || skip merging. That's complicated.
	ddor := strings.Index(dep.Reference, "||")
	eor := strings.Index(v.Reference, "||")
	if ddor == -1 && eor == -1 {
		// Add the comparisons together.
		newRef := v.Reference + ", " + dep.Reference
		v.Reference = newRef
		v.Pin = ""
		singleInfo("Combining %s semantic version constraints %s and %s", v.Name, v.Reference, dep.Reference)
		return v
	}
//.........这里部分代码省略.........

// VcsGet figures out how to fetch a dependency, and then gets it.
//
// VcsGet installs into the dest.
func VcsGet(dep *cfg.Dependency, dest, home string, cache, cacheGopath, useGopath bool) error {
	// When not skipping the $GOPATH look in it for a copy of the package
	if useGopath {
		// Check if the $GOPATH has a viable version to use and if so copy to vendor
		gps := gpath.Gopaths()
		for _, p := range gps {
			d := filepath.Join(p, "src", dep.Name)
			if _, err := os.Stat(d); err == nil {
				empty, err := gpath.IsDirectoryEmpty(d)
				if empty || err != nil {
					continue
				}

				repo, err := dep.GetRepo(d)
				if err != nil {
					continue
				}

				// Dirty repos have uncomitted changes.
				if repo.IsDirty() {
					continue
				}

				// Having found a repo we copy it to vendor and update it.
				msg.Info("Copying package %s from the GOPATH.", dep.Name)
				msg.Debug("Found %s in GOPATH at %s. Copying to %s", dep.Name, d, dest)
				err = gpath.CopyDir(d, dest)
				if err != nil {
					return err
				}

				// Update the repo in the vendor directory
				msg.Debug("Updating %s, now in the vendor path at %s", dep.Name, dest)
				repo, err = dep.GetRepo(dest)
				if err != nil {
					return err
				}
				err = repo.Update()
				if err != nil {
					return err
				}

				// If there is no reference set on the dep we try to checkout
				// the default branch.
				if dep.Reference == "" {
					db := defaultBranch(repo, home)
					if db != "" {
						err = repo.UpdateVersion(db)
						if err != nil && msg.Default.IsDebugging {
							msg.Debug("Attempting to set the version on %s to %s failed. Error %s", dep.Name, db, err)
						}
					}
				}
				return nil
			}
		}
	}

	// When opting in to cache in the GOPATH attempt to do put a copy there.
	if cacheGopath {

		// Since we didn't find an existing copy in the GOPATHs try to clone there.
		gp := gpath.Gopath()
		if gp != "" {
			d := filepath.Join(gp, "src", dep.Name)
			if _, err := os.Stat(d); os.IsNotExist(err) {
				// Empty directory so we checkout out the code here.
				msg.Debug("Retrieving %s to %s before copying to vendor", dep.Name, d)
				repo, err := dep.GetRepo(d)
				if err != nil {
					return err
				}
				repo.Get()

				branch := findCurrentBranch(repo)
				if branch != "" {
					// we know the default branch so we can store it in the cache
					var loc string
					if dep.Repository != "" {
						loc = dep.Repository
					} else {
						loc = "https://" + dep.Name
					}
					key, err := cacheCreateKey(loc)
					if err == nil {
						msg.Debug("Saving default branch for %s", repo.Remote())
						c := cacheRepoInfo{DefaultBranch: branch}
						err = saveCacheRepoData(key, c, home)
						if msg.Default.IsDebugging && err == errCacheDisabled {
							msg.Debug("Unable to cache default branch because caching is disabled")
						}
					}
				}

				msg.Debug("Copying %s from GOPATH at %s to %s", dep.Name, d, dest)
				err = gpath.CopyDir(d, dest)
				if err != nil {
//.........这里部分代码省略.........

// VcsUpdate updates to a particular checkout based on the VCS setting.
func VcsUpdate(dep *cfg.Dependency, dest, home string, cache, cacheGopath, useGopath, force, updateVendored bool) error {

	// If the dependency has already been pinned we can skip it. This is a
	// faster path so we don't need to resolve it again.
	if dep.Pin != "" {
		msg.Debug("Dependency %s has already been pinned. Fetching updates skipped.", dep.Name)
		return nil
	}

	msg.Info("Fetching updates for %s.\n", dep.Name)

	if filterArchOs(dep) {
		msg.Info("%s is not used for %s/%s.\n", dep.Name, runtime.GOOS, runtime.GOARCH)
		return nil
	}

	// If destination doesn't exist we need to perform an initial checkout.
	if _, err := os.Stat(dest); os.IsNotExist(err) {
		if err = VcsGet(dep, dest, home, cache, cacheGopath, useGopath); err != nil {
			msg.Warn("Unable to checkout %s\n", dep.Name)
			return err
		}
	} else {
		// At this point we have a directory for the package.

		// When the directory is not empty and has no VCS directory it's
		// a vendored files situation.
		empty, err := gpath.IsDirectoryEmpty(dest)
		if err != nil {
			return err
		}
		_, err = v.DetectVcsFromFS(dest)
		if updateVendored == false && empty == false && err == v.ErrCannotDetectVCS {
			msg.Warn("%s appears to be a vendored package. Unable to update. Consider the '--update-vendored' flag.\n", dep.Name)
		} else {

			if updateVendored == true && empty == false && err == v.ErrCannotDetectVCS {
				// A vendored package, no repo, and updating the vendored packages
				// has been opted into.
				msg.Info("%s is a vendored package. Updating.", dep.Name)
				err = os.RemoveAll(dest)
				if err != nil {
					msg.Error("Unable to update vendored dependency %s.\n", dep.Name)
					return err
				} else {
					dep.UpdateAsVendored = true
				}

				if err = VcsGet(dep, dest, home, cache, cacheGopath, useGopath); err != nil {
					msg.Warn("Unable to checkout %s\n", dep.Name)
					return err
				}

				return nil
			}

			repo, err := dep.GetRepo(dest)

			// Tried to checkout a repo to a path that does not work. Either the
			// type or endpoint has changed. Force is being passed in so the old
			// location can be removed and replaced with the new one.
			// Warning, any changes in the old location will be deleted.
			// TODO: Put dirty checking in on the existing local checkout.
			if (err == v.ErrWrongVCS || err == v.ErrWrongRemote) && force == true {
				var newRemote string
				if len(dep.Repository) > 0 {
					newRemote = dep.Repository
				} else {
					newRemote = "https://" + dep.Name
				}

				msg.Warn("Replacing %s with contents from %s\n", dep.Name, newRemote)
				rerr := os.RemoveAll(dest)
				if rerr != nil {
					return rerr
				}
				if err = VcsGet(dep, dest, home, cache, cacheGopath, useGopath); err != nil {
					msg.Warn("Unable to checkout %s\n", dep.Name)
					return err
				}
			} else if err != nil {
				return err
			} else if repo.IsDirty() {
				return fmt.Errorf("%s contains uncommited changes. Skipping update", dep.Name)
			} else {

				// Check if the current version is a tag or commit id. If it is
				// and that version is already checked out we can skip updating
				// which is faster than going out to the Internet to perform
				// an update.
				if dep.Reference != "" {
					version, err := repo.Version()
					if err != nil {
						return err
					}
					ib, err := isBranch(dep.Reference, repo)
					if err != nil {
						return err
					}
//.........这里部分代码省略.........

// VcsVersion set the VCS version for a checkout.
func VcsVersion(dep *cfg.Dependency, vend string) error {

	// If the dependency has already been pinned we can skip it. This is a
	// faster path so we don't need to resolve it again.
	if dep.Pin != "" {
		msg.Debug("Dependency %s has already been pinned. Setting version skipped.", dep.Name)
		return nil
	}

	cwd := filepath.Join(vend, dep.Name)

	// If there is no refernece configured there is nothing to set.
	if dep.Reference == "" {
		// Before exiting update the pinned version
		repo, err := dep.GetRepo(cwd)
		if err != nil {
			return err
		}
		dep.Pin, err = repo.Version()
		if err != nil {
			return err
		}
		return nil
	}

	// When the directory is not empty and has no VCS directory it's
	// a vendored files situation.
	empty, err := gpath.IsDirectoryEmpty(cwd)
	if err != nil {
		return err
	}
	_, err = v.DetectVcsFromFS(cwd)
	if empty == false && err == v.ErrCannotDetectVCS {
		msg.Warn("%s appears to be a vendored package. Unable to set new version. Consider the '--update-vendored' flag.\n", dep.Name)
	} else {
		repo, err := dep.GetRepo(cwd)
		if err != nil {
			return err
		}

		ver := dep.Reference
		// Referenes in Git can begin with a ^ which is similar to semver.
		// If there is a ^ prefix we assume it's a semver constraint rather than
		// part of the git/VCS commit id.
		if repo.IsReference(ver) && !strings.HasPrefix(ver, "^") {
			msg.Info("Setting version for %s to %s.\n", dep.Name, ver)
		} else {

			// Create the constraing first to make sure it's valid before
			// working on the repo.
			constraint, err := semver.NewConstraint(ver)

			// Make sure the constriant is valid. At this point it's not a valid
			// reference so if it's not a valid constrint we can exit early.
			if err != nil {
				msg.Warn("The reference '%s' is not valid\n", ver)
				return err
			}

			// Get the tags and branches (in that order)
			refs, err := getAllVcsRefs(repo)
			if err != nil {
				return err
			}

			// Convert and filter the list to semver.Version instances
			semvers := getSemVers(refs)

			// Sort semver list
			sort.Sort(sort.Reverse(semver.Collection(semvers)))
			found := false
			for _, v := range semvers {
				if constraint.Check(v) {
					found = true
					// If the constrint passes get the original reference
					ver = v.Original()
					break
				}
			}
			if found {
				msg.Info("Detected semantic version. Setting version for %s to %s.\n", dep.Name, ver)
			} else {
				msg.Warn("Unable to find semantic version for constraint %s %s\n", dep.Name, ver)
			}
		}
		if err := repo.UpdateVersion(ver); err != nil {
			msg.Error("Failed to set version to %s: %s\n", dep.Reference, err)
			return err
		}
		dep.Pin, err = repo.Version()
		if err != nil {
			return err
		}
	}

	return nil
}

// addPkgsToConfig adds the given packages to the config file.
//
// Along the way it:
// - ensures that this package is not in the ignore list
// - checks to see if this is already in the dependency list.
// - splits version of of package name and adds the version attribute
// - separates repo from packages
// - sets up insecure repo URLs where necessary
// - generates a list of subpackages
func addPkgsToConfig(conf *cfg.Config, names []string, insecure, nonInteract, testDeps bool) (int, error) {

	if len(names) == 1 {
		msg.Info("Preparing to install %d package.", len(names))
	} else {
		msg.Info("Preparing to install %d packages.", len(names))
	}
	numAdded := 0
	for _, name := range names {
		var version string
		parts := strings.Split(name, "#")
		if len(parts) > 1 {
			name = parts[0]
			version = parts[1]
		}

		msg.Info("Attempting to get package %s", name)

		root, subpkg := util.NormalizeName(name)
		if len(root) == 0 {
			return 0, fmt.Errorf("Package name is required for %q.", name)
		}

		if conf.HasDependency(root) {

			var moved bool
			var dep *cfg.Dependency
			// Move from DevImports to Imports
			if !testDeps && !conf.Imports.Has(root) && conf.DevImports.Has(root) {
				dep = conf.DevImports.Get(root)
				conf.Imports = append(conf.Imports, dep)
				conf.DevImports = conf.DevImports.Remove(root)
				moved = true
				numAdded++
				msg.Info("--> Moving %s from testImport to import", root)
			} else if testDeps && conf.Imports.Has(root) {
				msg.Warn("--> Test dependency %s already listed as import", root)
			}

			// Check if the subpackage is present.
			if subpkg != "" {
				if dep == nil {
					dep = conf.Imports.Get(root)
					if dep == nil && testDeps {
						dep = conf.DevImports.Get(root)
					}
				}
				if dep.HasSubpackage(subpkg) {
					if !moved {
						msg.Warn("--> Package %q is already in glide.yaml. Skipping", name)
					}
				} else {
					dep.Subpackages = append(dep.Subpackages, subpkg)
					msg.Info("--> Adding sub-package %s to existing import %s", subpkg, root)
					numAdded++
				}
			} else if !moved {
				msg.Warn("--> Package %q is already in glide.yaml. Skipping", root)
			}
			continue
		}

		if conf.HasIgnore(root) {
			msg.Warn("--> Package %q is set to be ignored in glide.yaml. Skipping", root)
			continue
		}

		dep := &cfg.Dependency{
			Name: root,
		}

		// When retriving from an insecure location set the repo to the
		// insecure location.
		if insecure {
			dep.Repository = "http://" + root
		}

		if version != "" {
			dep.Reference = version
		} else if !nonInteract {
			getWizard(dep)
		}

		if len(subpkg) > 0 {
			dep.Subpackages = []string{subpkg}
		}

		if dep.Reference != "" {
			msg.Info("--> Adding %s to your configuration with the version %s", dep.Name, dep.Reference)
		} else {
			msg.Info("--> Adding %s to your configuration", dep.Name)
//.........这里部分代码省略.........

func wizardFindVersions(d *cfg.Dependency) {
	l := cache.Location()
	remote := d.Remote()

	key, err := cache.Key(remote)
	if err != nil {
		msg.Debug("Problem generating cache key for %s: %s", remote, err)
		return
	}

	local := filepath.Join(l, "src", key)
	repo, err := vcs.NewRepo(remote, local)
	if err != nil {
		msg.Debug("Problem getting repo instance: %s", err)
		return
	}

	var useLocal bool
	if _, err = os.Stat(local); err == nil {
		useLocal = true
	}

	// Git endpoints allow for querying without fetching the codebase locally.
	// We try that first to avoid fetching right away. Is this premature
	// optimization?
	cc := true
	if !useLocal && repo.Vcs() == vcs.Git {
		out, err2 := exec.Command("git", "ls-remote", remote).CombinedOutput()
		if err2 == nil {
			cache.MemTouch(remote)
			cc = false
			lines := strings.Split(string(out), "\n")
			for _, i := range lines {
				ti := strings.TrimSpace(i)
				if found := createGitParseVersion.FindString(ti); found != "" {
					tg := strings.TrimPrefix(strings.TrimSuffix(found, "^{}"), "tags/")
					cache.MemPut(remote, tg)
					if d.Reference != "" && strings.HasPrefix(ti, d.Reference) {
						cache.MemSetCurrent(remote, tg)
					}
				}
			}
		}
	}

	if cc {
		cache.Lock(key)
		cache.MemTouch(remote)
		if _, err = os.Stat(local); os.IsNotExist(err) {
			repo.Get()
			branch := findCurrentBranch(repo)
			c := cache.RepoInfo{DefaultBranch: branch}
			err = cache.SaveRepoData(key, c)
			if err != nil {
				msg.Debug("Error saving cache repo details: %s", err)
			}
		} else {
			repo.Update()
		}
		tgs, err := repo.Tags()
		if err != nil {
			msg.Debug("Problem getting tags: %s", err)
		} else {
			for _, v := range tgs {
				cache.MemPut(remote, v)
			}
		}
		if d.Reference != "" && repo.IsReference(d.Reference) {
			tgs, err = repo.TagsFromCommit(d.Reference)
			if err != nil {
				msg.Debug("Problem getting tags for commit: %s", err)
			} else {
				if len(tgs) > 0 {
					for _, v := range tgs {
						if !(repo.Vcs() == vcs.Hg && v == "tip") {
							cache.MemSetCurrent(remote, v)
						}
					}
				}
			}
		}
		cache.Unlock(key)
	}
}

// VcsUpdate updates to a particular checkout based on the VCS setting.
func VcsUpdate(dep *cfg.Dependency, force bool, updated *UpdateTracker) error {

	// If the dependency has already been pinned we can skip it. This is a
	// faster path so we don't need to resolve it again.
	if dep.Pin != "" {
		msg.Debug("Dependency %s has already been pinned. Fetching updates skipped.", dep.Name)
		return nil
	}

	if updated.Check(dep.Name) {
		msg.Debug("%s was already updated, skipping.", dep.Name)
		return nil
	}
	updated.Add(dep.Name)

	if filterArchOs(dep) {
		msg.Info("%s is not used for %s/%s.\n", dep.Name, runtime.GOOS, runtime.GOARCH)
		return nil
	}

	key, err := cp.Key(dep.Remote())
	if err != nil {
		msg.Die("Cache key generation error: %s", err)
	}
	location := cp.Location()
	dest := filepath.Join(location, "src", key)

	// If destination doesn't exist we need to perform an initial checkout.
	if _, err := os.Stat(dest); os.IsNotExist(err) {
		msg.Info("--> Fetching %s.", dep.Name)
		if err = VcsGet(dep); err != nil {
			msg.Warn("Unable to checkout %s\n", dep.Name)
			return err
		}
	} else {
		// At this point we have a directory for the package.
		msg.Info("--> Fetching updates for %s.", dep.Name)

		// When the directory is not empty and has no VCS directory it's
		// a vendored files situation.
		empty, err := gpath.IsDirectoryEmpty(dest)
		if err != nil {
			return err
		}
		_, err = v.DetectVcsFromFS(dest)
		if empty == true && err == v.ErrCannotDetectVCS {
			msg.Warn("Cached version of %s is an empty directory. Fetching a new copy of the dependency.", dep.Name)
			msg.Debug("Removing empty directory %s", dest)
			err := os.RemoveAll(dest)
			if err != nil {
				return err
			}
			if err = VcsGet(dep); err != nil {
				msg.Warn("Unable to checkout %s\n", dep.Name)
				return err
			}
		} else {
			repo, err := dep.GetRepo(dest)

			// Tried to checkout a repo to a path that does not work. Either the
			// type or endpoint has changed. Force is being passed in so the old
			// location can be removed and replaced with the new one.
			// Warning, any changes in the old location will be deleted.
			// TODO: Put dirty checking in on the existing local checkout.
			if (err == v.ErrWrongVCS || err == v.ErrWrongRemote) && force == true {
				newRemote := dep.Remote()

				msg.Warn("Replacing %s with contents from %s\n", dep.Name, newRemote)
				rerr := os.RemoveAll(dest)
				if rerr != nil {
					return rerr
				}
				if err = VcsGet(dep); err != nil {
					msg.Warn("Unable to checkout %s\n", dep.Name)
					return err
				}

				repo, err = dep.GetRepo(dest)
				if err != nil {
					return err
				}
			} else if err != nil {
				return err
			} else if repo.IsDirty() {
				return fmt.Errorf("%s contains uncommitted changes. Skipping update", dep.Name)
			}

			ver := dep.Reference
			if ver == "" {
				ver = defaultBranch(repo)
			}
			// Check if the current version is a tag or commit id. If it is
			// and that version is already checked out we can skip updating
			// which is faster than going out to the Internet to perform
			// an update.
			if ver != "" {
				version, err := repo.Version()
				if err != nil {
					return err
//.........这里部分代码省略.........