Allow printing of nil Version/RelaxedVersion without panic

Author: cmaglie

relaxed_version.go

@@ -33,6 +33,9 @@ func ParseRelaxed(in string) *RelaxedVersion {
 }
 
 func (v *RelaxedVersion) String() string {
+	if v == nil {
+		return ""
+	}
 	if v.version != nil {
 		return v.version.String()
 	}

relaxed_version_test.go

@@ -91,3 +91,8 @@ func TestRelaxedVersionComparator(t *testing.T) {
 		ParseRelaxed("0.0.0+aaa.bbb"),
 	)
 }
+
+func TestNilRelaxedVersionString(t *testing.T) {
+	var nilVersion *RelaxedVersion
+	require.Equal(t, "", nilVersion.String())
+}

version.go

@@ -17,6 +17,9 @@ type Version struct {
 }
 
 func (v *Version) String() string {
+	if v == nil {
+		return ""
+	}
 	res := string(v.major)
 	if len(v.minor) > 0 {
 		res += "." + string(v.minor)

version_test.go

@@ -98,3 +98,8 @@ func TestVersionComparator(t *testing.T) {
 		MustParse("0.0.0-ab+aaa.bbb"),
 	)
 }
+
+func TestNilVersionString(t *testing.T) {
+	var nilVersion *Version
+	require.Equal(t, "", nilVersion.String())
+}