Address review comments.

ygen/protogen.go

@@ -425,7 +425,9 @@ func genProto3Msg(msg *yangDirectory, msgs map[string]*yangDirectory, state *gen
 					if _, ok := imports[childpath]; !ok {
 						imports[childpath] = true
 					}
-					pfx = fmt.Sprintf("%s.", stripPackagePrefix(parentPkg, childpkg))
+
+					p, _ := stripPackagePrefix(parentPkg, childpkg)
+					pfx = fmt.Sprintf("%s.", p)
 				}
 				fieldDef.Type = fmt.Sprintf("%s%s", pfx, childmsg.name)
 			}
@@ -917,7 +919,8 @@ func genListKeyProto(listPackage string, listName string, args protoDefinitionAr
 		ctag++
 	}
 
-	ltype := fmt.Sprintf("%s.%s", stripPackagePrefix(args.parentPackage, listPackage), listName)
+	p, _ := stripPackagePrefix(args.parentPackage, listPackage)
+	ltype := fmt.Sprintf("%s.%s", p, listName)
 	if listPackage == "" {
 		// Handle the case that the context of the list is already the base package.
 		ltype = listName
@@ -1063,17 +1066,18 @@ func protoSchemaPathAnnotation(msg *yangDirectory, field *yang.Entry, compressPa
 }
 
 // stripPackagePrefix removes the prefix of pfx from the path supplied. If pfx
-// is not a prefix of path the entire path is returned.
-func stripPackagePrefix(pfx, path string) string {
+// is not a prefix of path the entire path is returned. If the prefix was
+// stripped, the returned bool is set.
+func stripPackagePrefix(pfx, path string) (string, bool) {
 	pfxP := strings.Split(pfx, ".")
 	pathP := strings.Split(path, ".")
 
 	var i int
 	for i = range pfxP {
 		if pfxP[i] != pathP[i] {
-			return path
+			return path, false
 		}
 	}
 
-	return strings.Join(pathP[i+1:], ".")
+	return strings.Join(pathP[i+1:], "."), true
 }

ygen/protogen_test.go

@@ -1509,31 +1509,40 @@ func TestUnionFieldToOneOf(t *testing.T) {
 
 func TestStripPackagePrefix(t *testing.T) {
 	tests := []struct {
-		name     string
-		inPrefix string
-		inPath   string
-		want     string
+		name         string
+		inPrefix     string
+		inPath       string
+		want         string
+		wantStripped bool
 	}{{
-		name:     "invalid prefix at element one",
-		inPrefix: "one.two",
-		inPath:   "two.four",
-		want:     "two.four",
+		name:         "invalid prefix at element one",
+		inPrefix:     "one.two",
+		inPath:       "two.four",
+		want:         "two.four",
+		wantStripped: false,
 	}, {
-		name:     "single element prefix",
-		inPrefix: "one",
-		inPath:   "one.three",
-		want:     "three",
+		name:         "single element prefix",
+		inPrefix:     "one",
+		inPath:       "one.three",
+		want:         "three",
+		wantStripped: true,
 	}, {
-		name:     "longer prefix",
-		inPrefix: "one.two.three",
-		inPath:   "one.two.three.five",
-		want:     "five",
+		name:         "longer prefix",
+		inPrefix:     "one.two.three",
+		inPath:       "one.two.three.five",
+		want:         "five",
+		wantStripped: true,
 	}}
 
 	for _, tt := range tests {
-		if got := stripPackagePrefix(tt.inPrefix, tt.inPath); got != tt.want {
+		got, stripped := stripPackagePrefix(tt.inPrefix, tt.inPath)
+		if got != tt.want {
 			t.Errorf("%s: stripPackagePrefix(%s, %s): did not get expected output, got: %s, want: %s", tt.name, tt.inPrefix, tt.inPath, got, tt.want)
 		}
+
+		if stripped != tt.wantStripped {
+			t.Errorf("%s: stripPackagePrefix(%s, %s): did not get expected stipped status, got: %v, want: %v", tt.name, tt.inPrefix, tt.inPath, stripped, tt.wantStripped)
+		}
 	}
 
 }