// FromYaml takes a yaml string and converts it to a Config instance.
func FromYaml(yml string) (*Config, error) {
	c := &Config{}
	err := yaml.Unmarshal([]byte(yml), &c)
	if err != nil {
		return nil, err
	}

	// The ref property is for the legacy yaml file structure.
	// This sets the currect version to the ref if a version isn't
	// already set.
	for _, v := range c.Imports {
		if v.Reference == "" && v.Ref != "" {
			v.Reference = v.Ref
		}
		v.Ref = ""

		// Make sure only legitimate VCS are listed.
		v.VcsType = filterVcsType(v.VcsType)

		// Get the root name for the package
		o := v.Name
		v.Name = util.GetRootFromPackage(v.Name)
		subpkg := strings.TrimPrefix(o, v.Name)
		if len(subpkg) > 0 && subpkg != o {
			v.Subpackages = append(v.Subpackages, strings.TrimPrefix(subpkg, "/"))
		}
	}
	for _, v := range c.DevImports {
		if v.Reference == "" && v.Ref != "" {
			v.Reference = v.Ref
		}
		v.Ref = ""

		v.VcsType = filterVcsType(v.VcsType)

		// Get the root name for the package
		o := v.Name
		v.Name = util.GetRootFromPackage(v.Name)
		subpkg := strings.TrimPrefix(o, v.Name)
		if len(subpkg) > 0 && subpkg != o {
			v.Subpackages = append(v.Subpackages, subpkg)
		}
	}

	c.Imports, err = c.Imports.DeDupe()
	if err != nil {
		return c, err
	}
	c.DevImports, err = c.DevImports.DeDupe()
	if err != nil {
		return c, err
	}

	return c, nil
}

func (m *MissingPackageHandler) NotFound(pkg string) (bool, error) {
	root := util.GetRootFromPackage(pkg)

	// Skip any references to the root package.
	if root == m.RootPackage {
		return false, nil
	}

	dest := filepath.Join(m.destination, root)

	// This package may have been placed on the list to look for when it wasn't
	// downloaded but it has since been downloaded before coming to this entry.
	if _, err := os.Stat(dest); err == nil {
		return true, nil
	}

	msg.Info("Fetching %s into %s", pkg, m.destination)

	d := m.Config.Imports.Get(root)
	// If the dependency is nil it means the Config doesn't yet know about it.
	if d == nil {
		d = m.Use.Get(root)
		// We don't know about this dependency so we create a basic instance.
		if d == nil {
			d = &cfg.Dependency{Name: root}
		}

		m.Config.Imports = append(m.Config.Imports, d)
	}
	if err := VcsGet(d, dest, m.home, m.cache, m.cacheGopath, m.useGopath); err != nil {
		return false, err
	}
	return true, nil
}

// InVendor updates a package in the vendor/ directory to make sure the latest
// is available.
func (m *MissingPackageHandler) InVendor(pkg string) error {
	root := util.GetRootFromPackage(pkg)

	// Skip any references to the root package.
	if root == m.Config.Name {
		return nil
	}

	dest := filepath.Join(m.destination, root)

	d := m.Config.Imports.Get(root)
	// If the dependency is nil it means the Config doesn't yet know about it.
	if d == nil {
		d, _ = m.Use.Get(root)
		// We don't know about this dependency so we create a basic instance.
		if d == nil {
			d = &cfg.Dependency{Name: root}
		}

		m.Config.Imports = append(m.Config.Imports, d)
	}

	if err := VcsUpdate(d, dest, m.home, m.cache, m.cacheGopath, m.useGopath, m.force, m.updateVendored, m.updated); err != nil {
		return err
	}

	return nil
}

// GetAll gets zero or more repos.
//
// This takes a package name, normalizes it, finds the repo, and installs it.
// It's the workhorse behind `glide get`.
//
// Params:
//	- packages ([]string): Package names to get.
// 	- verbose (bool): default false
//
// Returns:
// 	- []*Dependency: A list of constructed dependencies.
func GetAll(c cookoo.Context, p *cookoo.Params) (interface{}, cookoo.Interrupt) {
	names := p.Get("packages", []string{}).([]string)
	cfg := p.Get("conf", nil).(*yaml.Config)
	insecure := p.Get("insecure", false).(bool)
	home := p.Get("home", "").(string)
	cache := p.Get("cache", false).(bool)
	cacheGopath := p.Get("cacheGopath", false).(bool)
	skipGopath := p.Get("skipGopath", false).(bool)

	Info("Preparing to install %d package.", len(names))

	deps := []*yaml.Dependency{}
	for _, name := range names {
		cwd, err := VendorPath(c)
		if err != nil {
			return nil, err
		}

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

		if cfg.HasDependency(root) {
			Warn("Package %q is already in glide.yaml. Skipping", root)
			continue
		}

		dest := path.Join(cwd, root)

		if err != nil {
			Error("Could not construct repo for %q: %s", name, err)
			return false, err
		}

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

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

		subpkg := strings.TrimPrefix(name, root)
		if len(subpkg) > 0 && subpkg != "/" {
			dep.Subpackages = []string{subpkg}
		}
		if err := VcsGet(dep, dest, home, cache, cacheGopath, skipGopath); err != nil {
			return dep, err
		}

		cfg.Imports = append(cfg.Imports, dep)

		deps = append(deps, dep)

	}
	return deps, nil
}

func (m *MissingPackageHandler) fetchToCache(pkg string, addTest bool) error {
	root := util.GetRootFromPackage(pkg)
	// Skip any references to the root package.
	if root == m.Config.Name {
		return nil
	}

	d := m.Config.Imports.Get(root)
	if d == nil && addTest {
		d = m.Config.DevImports.Get(root)
	}

	// If the dependency is nil it means the Config doesn't yet know about it.
	if d == nil {
		d, _ = m.Use.Get(root)
		// We don't know about this dependency so we create a basic instance.
		if d == nil {
			d = &cfg.Dependency{Name: root}
		}

		if addTest {
			m.Config.DevImports = append(m.Config.DevImports, d)
		} else {
			m.Config.Imports = append(m.Config.Imports, d)
		}
	}

	return VcsUpdate(d, m.force, m.updated)
}

// UnmarshalYAML is a hook for gopkg.in/yaml.v2 in the unmarshaling process
func (d *Dependency) UnmarshalYAML(unmarshal func(interface{}) error) error {
	newDep := &dep{}
	err := unmarshal(&newDep)
	if err != nil {
		return err
	}
	d.Name = newDep.Name
	d.Reference = newDep.Reference
	d.Repository = newDep.Repository
	d.VcsType = newDep.VcsType
	d.Subpackages = newDep.Subpackages
	d.Arch = newDep.Arch
	d.Os = newDep.Os

	if d.Reference == "" && newDep.Ref != "" {
		d.Reference = newDep.Ref
	}

	// Make sure only legitimate VCS are listed.
	d.VcsType = filterVcsType(d.VcsType)

	// Get the root name for the package
	o := d.Name
	d.Name = util.GetRootFromPackage(d.Name)
	subpkg := strings.TrimPrefix(o, d.Name)
	if len(subpkg) > 0 && subpkg != "/" {
		d.Subpackages = append(d.Subpackages, strings.TrimPrefix(subpkg, "/"))
	}

	return nil
}

// NormalizeName takes a package name and normalizes it to the top level package.
//
// For example, golang.org/x/crypto/ssh becomes golang.org/x/crypto. 'ssh' is
// returned as extra data.
func NormalizeName(name string) (string, string) {

	// Fastpath check if a name in the GOROOT. There is an issue when a pkg
	// is in the GOROOT and GetRootFromPackage tries to look it up because it
	// expects remote names.
	b, err := util.GetBuildContext()
	if err == nil {
		p := filepath.Join(b.GOROOT, "src", filepath.FromSlash(name))
		if _, err := os.Stat(p); err == nil {
			return name, ""
		}
	}

	root := util.GetRootFromPackage(name)
	extra := strings.TrimPrefix(name, root)
	if len(extra) > 0 && extra != "/" {
		extra = strings.TrimPrefix(extra, "/")
	} else {
		// If extra is / (which is what it would be here) we want to return ""
		extra = ""
	}

	return root, extra

	// parts := strings.SplitN(name, "/", 4)
	// extra := ""
	// if len(parts) < 3 {
	// 	return name, extra
	// }
	// if len(parts) == 4 {
	// 	extra = parts[3]
	// }
	// return strings.Join(parts[0:3], "/"), extra
}

func (m *MissingPackageHandler) OnGopath(pkg string) (bool, error) {
	// If useGopath is false, we fall back to the strategy of fetching from
	// remote.
	if !m.useGopath {
		return m.NotFound(pkg)
	}

	root := util.GetRootFromPackage(pkg)

	// Skip any references to the root package.
	if root == m.RootPackage {
		return false, nil
	}

	msg.Info("Copying package %s from the GOPATH.", pkg)
	dest := filepath.Join(m.destination, pkg)
	// Find package on Gopath
	for _, gp := range gpath.Gopaths() {
		src := filepath.Join(gp, pkg)
		// FIXME: Should probably check if src is a dir or symlink.
		if _, err := os.Stat(src); err == nil {
			if err := os.MkdirAll(dest, os.ModeDir|0755); err != nil {
				return false, err
			}
			if err := gpath.CopyDir(src, dest); err != nil {
				return false, err
			}
			return true, nil
		}
	}

	msg.Error("Could not locate %s on the GOPATH, though it was found before.", pkg)
	return false, nil
}

// Process imports dependencies for a package
func (d *VersionHandler) Process(pkg string) (e error) {
	root := util.GetRootFromPackage(pkg)

	// Skip any references to the root package.
	if root == d.RootPackage {
		return nil
	}

	// We have not tried to import, yet.
	// Should we look in places other than the root of the project?
	if d.Imported[root] == false {
		d.Imported[root] = true
		p := filepath.Join(d.Destination, root)
		f, deps, err := importer.Import(p)
		if f && err == nil {
			for _, dep := range deps {

				// The fist one wins. Would something smater than this be better?
				exists := d.Use.Get(dep.Name)
				if exists == nil && (dep.Reference != "" || dep.Repository != "") {
					d.Use.Add(dep.Name, dep)
				}
			}
		} else if err != nil {
			msg.Error("Unable to import from %s. Err: %s", root, err)
			e = err
		}
	}

	return
}

// NotFound attempts to retrieve a package when not found in the local vendor/
// folder. It will attempt to get it from the remote location info.
func (m *MissingPackageHandler) NotFound(pkg string, addTest bool) (bool, error) {
	root := util.GetRootFromPackage(pkg)
	// Skip any references to the root package.
	if root == m.Config.Name {
		return false, nil
	}

	dest := filepath.Join(m.destination, root)

	// This package may have been placed on the list to look for when it wasn't
	// downloaded but it has since been downloaded before coming to this entry.
	if _, err := os.Stat(dest); err == nil {
		// Make sure the location contains files. It may be an empty directory.
		empty, err := gpath.IsDirectoryEmpty(dest)
		if err != nil {
			return false, err
		}
		if empty {
			msg.Warn("%s is an existing location with no files. Fetching a new copy of the dependency.", dest)
			msg.Debug("Removing empty directory %s", dest)
			err := os.RemoveAll(dest)
			if err != nil {
				msg.Debug("Installer error removing directory %s: %s", dest, err)
				return false, err
			}
		} else {
			msg.Debug("Found %s", dest)
			return true, nil
		}
	}

	msg.Info("Fetching %s into %s", pkg, m.destination)

	d := m.Config.Imports.Get(root)
	if d == nil && addTest {
		d = m.Config.DevImports.Get(root)
	}

	// If the dependency is nil it means the Config doesn't yet know about it.
	if d == nil {
		d, _ = m.Use.Get(root)
		// We don't know about this dependency so we create a basic instance.
		if d == nil {
			d = &cfg.Dependency{Name: root}
		}
		if addTest {
			m.Config.DevImports = append(m.Config.DevImports, d)
		} else {
			m.Config.Imports = append(m.Config.Imports, d)
		}
	}
	if err := VcsGet(d, dest, m.home, m.cache, m.cacheGopath, m.useGopath); err != nil {
		return false, err
	}
	return true, nil
}

func parseGodepGodeps(dir string) ([]*cfg.Dependency, error) {
	path := filepath.Join(dir, "Godeps", "Godeps.json")
	if _, err := os.Stat(path); err != nil {
		return []*cfg.Dependency{}, nil
	}
	Info("Found Godeps.json file.\n")

	buf := []*cfg.Dependency{}

	godeps := new(Godeps)

	// Get a handle to the file.
	file, err := os.Open(path)
	if err != nil {
		return buf, err
	}
	defer file.Close()

	dec := json.NewDecoder(file)
	if err := dec.Decode(godeps); err != nil {
		return buf, err
	}

	// Info("Importing %d packages from %s.\n", len(godeps.Deps), godeps.ImportPath)
	seen := map[string]bool{}

	for _, d := range godeps.Deps {
		// Info("Adding package %s\n", d.ImportPath)
		pkg := util.GetRootFromPackage(d.ImportPath)
		sub := strings.TrimPrefix(d.ImportPath, pkg)
		sub = strings.TrimPrefix(sub, "/")
		if _, ok := seen[pkg]; ok {
			if len(sub) == 0 {
				continue
			}
			// Modify existing dep with additional subpackages.
			for _, dep := range buf {
				if dep.Name == pkg {
					dep.Subpackages = append(dep.Subpackages, sub)
				}
			}
		} else {
			seen[pkg] = true
			dep := &cfg.Dependency{Name: pkg, Reference: d.Rev}
			if len(sub) > 0 {
				dep.Subpackages = []string{sub}
			}
			buf = append(buf, dep)
		}
	}

	return buf, nil
}

// SetVersion sets the version for a package. If that package version is already
// set it handles the case by:
// - keeping the already set version
// - proviting messaging about the version conflict
// TODO(mattfarina): The way version setting happens can be improved. Currently not optimal.
func (d *VersionHandler) SetVersion(pkg string) (e error) {
	root := util.GetRootFromPackage(pkg)

	// Skip any references to the root package.
	if root == d.Config.Name {
		return nil
	}

	v := d.Config.Imports.Get(root)

	dep, req := d.Use.Get(root)
	if dep != nil && v != nil {
		if v.Reference == "" && dep.Reference != "" {
			v.Reference = dep.Reference
			// Clear the pin, if set, so the new version can be used.
			v.Pin = ""
			dep = v
		} else if v.Reference != "" && dep.Reference != "" && v.Reference != dep.Reference {
			dest := filepath.Join(d.Destination, filepath.FromSlash(v.Name))
			dep = determineDependency(v, dep, dest, req)
		} else {
			dep = v
		}

	} else if v != nil {
		dep = v
	} else if dep != nil {
		// We've got an imported dependency to use and don't already have a
		// record of it. Append it to the Imports.
		d.Config.Imports = append(d.Config.Imports, dep)
	} else {
		// If we've gotten here we don't have any depenency objects.
		r, sp := util.NormalizeName(pkg)
		dep = &cfg.Dependency{
			Name: r,
		}
		if sp != "" {
			dep.Subpackages = []string{sp}
		}
		d.Config.Imports = append(d.Config.Imports, dep)
	}

	err := VcsVersion(dep, d.Destination)
	if err != nil {
		msg.Warn("Unable to set version on %s to %s. Err: %s", root, dep.Reference, err)
		e = err
	}

	return
}

// SetVersion sets the version for a package. If that package version is already
// set it handles the case by:
// - keeping the already set version
// - proviting messaging about the version conflict
// TODO(mattfarina): The way version setting happens can be improved. Currently not optimal.
func (d *VersionHandler) SetVersion(pkg string, addTest bool) (e error) {
	root := util.GetRootFromPackage(pkg)

	// Skip any references to the root package.
	if root == d.Config.Name {
		return nil
	}

	v := d.Config.Imports.Get(root)
	if addTest {
		if v == nil {
			v = d.Config.DevImports.Get(root)
		} else if d.Config.DevImports.Has(root) {
			// Both imports and test imports lists the same dependency.
			// There are import chains (because the import tree is resolved
			// before the test tree) that can cause this.
			tempD := d.Config.DevImports.Get(root)
			if tempD.Reference != v.Reference {
				msg.Warn("Using import %s (version %s) for test instead of testImport (version %s).", v.Name, v.Reference, tempD.Reference)
			}
			// TODO(mattfarina): Note repo difference in a warning.
		}
	}

	dep, req := d.Use.Get(root)
	if dep != nil && v != nil {
		if v.Reference == "" && dep.Reference != "" {
			v.Reference = dep.Reference
			// Clear the pin, if set, so the new version can be used.
			v.Pin = ""
			dep = v
		} else if v.Reference != "" && dep.Reference != "" && v.Reference != dep.Reference {
			dest := d.pkgPath(pkg)
			dep = determineDependency(v, dep, dest, req)
		} else {
			dep = v
		}

	} else if v != nil {
		dep = v
	} else if dep != nil {
		// We've got an imported dependency to use and don't already have a
		// record of it. Append it to the Imports.
		if addTest {
			d.Config.DevImports = append(d.Config.DevImports, dep)
		} else {
			d.Config.Imports = append(d.Config.Imports, dep)
		}
	} else {
		// If we've gotten here we don't have any depenency objects.
		r, sp := util.NormalizeName(pkg)
		dep = &cfg.Dependency{
			Name: r,
		}
		if sp != "" {
			dep.Subpackages = []string{sp}
		}
		if addTest {
			d.Config.DevImports = append(d.Config.DevImports, dep)
		} else {
			d.Config.Imports = append(d.Config.Imports, dep)
		}
	}

	err := VcsVersion(dep)
	if err != nil {
		msg.Warn("Unable to set version on %s to %s. Err: %s", root, dep.Reference, err)
		e = err
	}

	return
}

// GetAll gets zero or more repos.
//
// This takes a package name, normalizes it, finds the repo, and installs it.
// It's the workhorse behind `glide get`.
//
// Params:
//	- packages ([]string): Package names to get.
// 	- verbose (bool): default false
//
// Returns:
// 	- []*Dependency: A list of constructed dependencies.
func GetAll(c cookoo.Context, p *cookoo.Params) (interface{}, cookoo.Interrupt) {
	names := p.Get("packages", []string{}).([]string)
	conf := p.Get("conf", nil).(*cfg.Config)
	insecure := p.Get("insecure", false).(bool)

	Info("Preparing to install %d package.", len(names))

	deps := []*cfg.Dependency{}
	for _, name := range names {
		var version string
		parts := strings.Split(name, "#")
		if len(parts) > 1 {
			name = parts[0]
			version = parts[1]
		}

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

		if conf.HasDependency(root) {
			Warn("Package %q is already in glide.yaml. Skipping", root)
			continue
		}

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

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

		if version != "" {
			dep.Reference = version
		}

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

		subpkg := strings.TrimPrefix(name, root)
		if len(subpkg) > 0 && subpkg != "/" {
			dep.Subpackages = []string{subpkg}
		}

		if dep.Reference != "" {
			Info("Importing %s with the version %s", dep.Name, dep.Reference)
		} else {
			Info("Importing %s", dep.Name)
		}

		conf.Imports = append(conf.Imports, dep)

		deps = append(deps, dep)

	}

	Info("Walking the dependency tree to calculate versions")
	return deps, nil
}

// GuessDeps tries to get the dependencies for the current directory.
//
// Params
//  - dirname (string): Directory to use as the base. Default: "."
//  - skipImport (book): Whether to skip importing from Godep, GPM, and gb
func GuessDeps(c cookoo.Context, p *cookoo.Params) (interface{}, cookoo.Interrupt) {
	buildContext, err := util.GetBuildContext()
	if err != nil {
		return nil, err
	}
	base := p.Get("dirname", ".").(string)
	skipImport := p.Get("skipImport", false).(bool)
	name := guessPackageName(buildContext, base)

	Info("Generating a YAML configuration file and guessing the dependencies")

	config := new(cfg.Config)

	// Get the name of the top level package
	config.Name = name

	// Import by looking at other package managers and looking over the
	// entire directory structure.

	// Attempt to import from other package managers.
	if !skipImport {
		Info("Attempting to import from other package managers (use --skip-import to skip)")
		deps := []*cfg.Dependency{}
		absBase, err := filepath.Abs(base)
		if err != nil {
			return nil, err
		}

		if d, ok := guessImportGodep(absBase); ok {
			Info("Importing Godep configuration")
			Warn("Godep uses commit id versions. Consider using Semantic Versions with Glide")
			deps = d
		} else if d, ok := guessImportGPM(absBase); ok {
			Info("Importing GPM configuration")
			deps = d
		} else if d, ok := guessImportGB(absBase); ok {
			Info("Importing GB configuration")
			deps = d
		}

		for _, i := range deps {
			Info("Found imported reference to %s\n", i.Name)
			config.Imports = append(config.Imports, i)
		}
	}

	// Resolve dependencies by looking at the tree.
	r, err := dependency.NewResolver(base)
	if err != nil {
		return nil, err
	}

	h := &dependency.DefaultMissingPackageHandler{Missing: []string{}, Gopath: []string{}}
	r.Handler = h

	sortable, err := r.ResolveLocal(false)
	if err != nil {
		return nil, err
	}

	sort.Strings(sortable)

	vpath := r.VendorDir
	if !strings.HasSuffix(vpath, "/") {
		vpath = vpath + string(os.PathSeparator)
	}

	for _, pa := range sortable {
		n := strings.TrimPrefix(pa, vpath)
		root := util.GetRootFromPackage(n)

		if !config.HasDependency(root) {
			Info("Found reference to %s\n", n)
			d := &cfg.Dependency{
				Name: root,
			}
			subpkg := strings.TrimPrefix(n, root)
			if len(subpkg) > 0 && subpkg != "/" {
				d.Subpackages = []string{subpkg}
			}
			config.Imports = append(config.Imports, d)
		} else {
			subpkg := strings.TrimPrefix(n, root)
			if len(subpkg) > 0 && subpkg != "/" {
				subpkg = strings.TrimPrefix(subpkg, "/")
				d := config.Imports.Get(root)
				f := false
				for _, v := range d.Subpackages {
					if v == subpkg {
						f = true
					}
				}
				if !f {
					Info("Adding sub-package %s to %s\n", subpkg, root)
					d.Subpackages = append(d.Subpackages, subpkg)
//.........这里部分代码省略.........

// 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
// - seperates repo from packages
// - sets up insecure repo URLs where necessary
// - generates a list of subpackages
func addPkgsToConfig(conf *cfg.Config, names []string, insecure bool) error {

	msg.Info("Preparing to install %d package.", len(names))

	for _, name := range names {
		var version string
		parts := strings.Split(name, "#")
		if len(parts) > 1 {
			name = parts[0]
			version = parts[1]
		}

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

		if conf.HasDependency(root) {

			// Check if the subpackage is present.
			subpkg := strings.TrimPrefix(name, root)
			subpkg = strings.TrimPrefix(subpkg, "/")
			if subpkg != "" {
				found := false
				dep := conf.Imports.Get(root)
				for _, s := range dep.Subpackages {
					if s == subpkg {
						found = true
						break
					}
				}
				if found {
					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)
				}
			} else {
				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,
		}

		if version != "" {
			dep.Reference = version
		}

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

		subpkg := strings.TrimPrefix(name, root)
		if len(subpkg) > 0 && subpkg != "/" {
			dep.Subpackages = []string{strings.TrimPrefix(subpkg, "/")}
		}

		if dep.Reference != "" {
			msg.Info("Importing %s with the version %s", dep.Name, dep.Reference)
		} else {
			msg.Info("Importing %s", dep.Name)
		}

		conf.Imports = append(conf.Imports, dep)
	}
	return nil
}

// mergeGuess guesses dependencies and merges.
//
// This always returns true because it always handles the job of searching
// for dependencies. So generally it should be the last merge strategy
// that you try.
func mergeGuess(dir, pkg string, f *flattening, scanned map[string]bool) ([]string, bool) {
	deps := f.deps
	Info("Scanning %s for dependencies.", pkg)
	buildContext, err := util.GetBuildContext()
	if err != nil {
		Warn("Could not scan package %q: %s", pkg, err)
		return []string{}, false
	}

	res := []string{}

	if _, err := os.Stat(dir); err != nil {
		Warn("Directory is missing: %s", dir)
		return res, true
	}

	d := walkDeps(buildContext, dir, pkg)
	for _, oname := range d {
		if _, ok := scanned[oname]; ok {
			//Info("===> Scanned %s already. Skipping", name)
			continue
		}
		Debug("=> Scanning %s", oname)
		name, _ := NormalizeName(oname)
		//if _, ok := deps[name]; ok {
		//scanned[oname] = true
		//Debug("====> Seen %s already. Skipping", name)
		//continue
		//}
		if f.conf.HasIgnore(name) {
			Debug("==> Skipping %s because it is on the ignore list", name)
			continue
		}

		found := findPkg(buildContext, name, dir)
		switch found.PType {
		case ptypeUnknown:
			Info("==> Unknown %s (%s)", name, oname)
			Debug("✨☆ Undownloaded dependency: %s", name)
			repo := util.GetRootFromPackage(name)
			nd := &cfg.Dependency{
				Name:       name,
				Repository: "https://" + repo,
			}
			deps[name] = nd
			res = append(res, name)
		case ptypeGoroot, ptypeCgo:
			scanned[oname] = true
			// Why do we break rather than continue?
			break
		default:
			// We're looking for dependencies that might exist in $GOPATH
			// but not be on vendor. We add any that are on $GOPATH.
			if _, ok := deps[name]; !ok {
				Debug("✨☆ GOPATH dependency: %s", name)
				nd := &cfg.Dependency{Name: name}
				deps[name] = nd
				res = append(res, name)
			}
			scanned[oname] = true
		}
	}

	return res, true
}