fix: fix parse error for ModSpec from str

Signed-off-by: zongz <[email protected]>

pkg/downloader/source.go

@@ -522,7 +522,8 @@ func (ps *ModSpec) FromString(registryStr string) error {
 	}
 
 	if parts[1] == "" {
-		return errors.New("invalid package reference")
+		ps.Name = parts[0]
+		return nil
 	}
 
 	ps.Name = parts[0]

pkg/downloader/source_test.go

@@ -0,0 +1,29 @@
+package downloader
+
+import (
+	"testing"
+
+	"gotest.tools/v3/assert"
+)
+
+func TestParseModSpecFromStr(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected ModSpec
+	}{
+		{"subhelloworld:0.0.1", ModSpec{Name: "subhelloworld", Version: "0.0.1"}},
+		{"subhelloworld", ModSpec{Name: "subhelloworld", Version: ""}},
+		{"subhelloworld:", ModSpec{Name: "subhelloworld", Version: ""}},
+		{":0.0.1", ModSpec{Name: "", Version: "0.0.1"}},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.input, func(t *testing.T) {
+			modspec := ModSpec{}
+			err := modspec.FromString(tt.input)
+			assert.NilError(t, err)
+			assert.Equal(t, modspec.Name, tt.expected.Name)
+			assert.Equal(t, modspec.Version, tt.expected.Version)
+		})
+	}
+}