Load repos status simultaneously with goroutines

Also, refactor printer interface.

pkg/print/dump.go

@@ -4,13 +4,6 @@ import (
 	"strings"
 )
 
-// DumpRepo is a git repository printable into a dump file.
-type DumpRepo interface {
-	Path() string
-	Remote() (string, error)
-	CurrentBranch() (string, error)
-}
-
 // DumpPrinter prints a list of repos in a dump file format.
 type DumpPrinter struct{}
 
@@ -21,20 +14,14 @@ func NewDumpPrinter() *DumpPrinter {
 
 // Print generates a list of repos URLs. Each line contains a URL and, if applicable, a currently checked out branch name.
 // It's a way to dump all repositories managed by git-get and is supposed to be consumed by `git get --dump`.
-func (p *DumpPrinter) Print(repos []DumpRepo) string {
+func (p *DumpPrinter) Print(repos []Printable) string {
 	var str strings.Builder
 
 	for i, r := range repos {
-		url, err := r.Remote()
-		if err != nil {
-			continue
-			// TODO: handle error?
-		}
+		str.WriteString(r.Remote())
 
-		str.WriteString(url)
-
-		current, err := r.CurrentBranch()
-		if err != nil || current != detached {
+		// TODO: if head is detached maybe we should get the revision it points to in case it's a tag
+		if current := r.Current(); current != "" && current != head {
 			str.WriteString(" " + current)
 		}