Glide install skips fetch when it is up to date

repo/installer.go

@@ -111,8 +111,8 @@ func (i *Installer) Install(lock *cfg.Lockfile, conf *cfg.Config) (*cfg.Config,
 
  msg.Info("Downloading dependencies. Please wait...")
 
- ConcurrentUpdate(newConf.Imports, cwd, i, newConf)
- ConcurrentUpdate(newConf.DevImports, cwd, i, newConf)
+ LazyConcurrentUpdate(newConf.Imports, cwd, i, newConf)
+ LazyConcurrentUpdate(newConf.DevImports, cwd, i, newConf)
  return newConf, nil
 }
 
@@ -302,6 +302,43 @@ func (i *Installer) List(conf *cfg.Config) []*cfg.Dependency {
  return conf.Imports
 }
 
+// LazyConcurrentUpdate updates only deps that are not already checkout out at the right version.
+//
+// This is only safe when updating from a lock file.
+func LazyConcurrentUpdate(deps []*cfg.Dependency, cwd string, i *Installer, c *cfg.Config) error {
+
+ newDeps := []*cfg.Dependency{}
+ for _, dep := range deps {
+ destPath := filepath.Join(i.VendorPath(), dep.Name)
+
+ // Get a VCS object for this directory
+ repo, err := dep.GetRepo(destPath)
+ if err != nil {
+ newDeps = append(newDeps, dep)
+ continue
+ }
+
+ ver, err := repo.Version()
+ if err != nil {
+ newDeps = append(newDeps, dep)
+ continue
+ }
+
+ if ver == dep.Reference {
+ msg.Info("--> Found desired version %s %s!", dep.Name, dep.Reference)
+ continue
+ }
+
+ msg.Debug("--> Queue %s for update (%s != %s).", dep.Name, ver, dep.Reference)
+ newDeps = append(newDeps, dep)
+ }
+ if len(newDeps) > 0 {
+ return ConcurrentUpdate(newDeps, cwd, i, c)
+ }
+
+ return nil
+}
+
 // ConcurrentUpdate takes a list of dependencies and updates in parallel.
 func ConcurrentUpdate(deps []*cfg.Dependency, cwd string, i *Installer, c *cfg.Config) error {
  done := make(chan struct{}, concurrentWorkers)

repo/vcs.go

@@ -203,14 +203,14 @@ func VcsVersion(dep *cfg.Dependency, vend string) error {
  }
 
  ver := dep.Reference
- // Referenes in Git can begin with a ^ which is similar to semver.
+ // References 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
+ // Create the constraint first to make sure it's valid before
  // working on the repo.
  constraint, err := semver.NewConstraint(ver)