Only highlight unique repositories in estimate

Keep printing all needed modules recursively, but instead of only
dimming the duplicated modules, we also dim the rest of the import path
after the repo root, and modules whose repo root has already been
printed. This allows to only highlight the repository names (the actual
thing that we package in Debian) and only once, so it give a better
appreciation of the work packaging work required.

estimate.go

@@ -174,6 +174,7 @@ func estimate(importpath string) error {
 	// Analyse the dependency graph
 	var lines []string
 	seen := make(map[string]bool)
+	rrseen := make(map[string]bool)
 	needed := make(map[string]int)
 	var visit func(n *Node, indent int)
 	visit = func(n *Node, indent int) {
@@ -198,6 +199,14 @@ func estimate(importpath string) error {
 			if _, ok := golangBinaries[mod]; ok {
 				return // already packaged in Debian
 			}
+			var repoRoot string
+			rr, err := vcs.RepoRootForImportPath(mod, false)
+			if err != nil {
+				log.Printf("Could not determine repo path for import path %q: %v\n", mod, err)
+				repoRoot = mod
+			} else {
+				repoRoot = rr.Root
+			}
 			var debianVersion string
 			// Check for potential other major versions already in Debian.
 			for _, otherVersion := range otherVersions(mod) {
@@ -210,21 +219,27 @@ func estimate(importpath string) error {
 				// When multiple modules are developped in the same repo,
 				// the repo root is often used as the import path metadata
 				// in Debian, so we do a last try with that.
-				rr, err := vcs.RepoRootForImportPath(mod, false)
-				if err != nil {
-					log.Printf("Could not determine repo path for import path %q: %v\n", mod, err)
-				} else if _, ok := golangBinaries[rr.Root]; ok {
+				if _, ok := golangBinaries[repoRoot]; ok {
 					// Log info to indicate that it is an approximate match
 					// but consider that it is packaged and skip the children.
-					log.Printf("%s is packaged as %s in Debian", mod, rr.Root)
+					log.Printf("%s is packaged as %s in Debian", mod, repoRoot)
 					return
 				}
 			}
-			if debianVersion != "" {
-				lines = append(lines, fmt.Sprintf("%s%s\t(%s in Debian)", strings.Repeat("  ", indent), mod, debianVersion))
+			line := strings.Repeat("  ", indent)
+			if rrseen[repoRoot] {
+				line += fmt.Sprintf("\033[90m%s\033[0m", mod)
+			} else if strings.HasPrefix(mod, repoRoot) && len(mod) > len(repoRoot) {
+				suffix := mod[len(repoRoot):]
+				line += fmt.Sprintf("%s\033[90m%s\033[0m", repoRoot, suffix)
 			} else {
-				lines = append(lines, fmt.Sprintf("%s%s", strings.Repeat("  ", indent), mod))
+				line += mod
+			}
+			if debianVersion != "" {
+				line += fmt.Sprintf("\t(%s in Debian)", debianVersion)
 			}
+			lines = append(lines, line)
+			rrseen[repoRoot] = true
 			needed[mod] = 1
 		}
 		for _, n := range n.children {