licensescan: Add simple license crosscheck (#3682)

Author: justinsb

tools/licensescan/licensedb_test.go

@@ -0,0 +1,64 @@
+package main
+
+import (
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"sigs.k8s.io/yaml"
+)
+
+// Test that the license didn't change for the same module
+func TestLicensesForConsistency(t *testing.T) {
+	files := make(map[string]*moduleInfo)
+
+	if err := filepath.Walk("modules", func(p string, info fs.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+
+		if info.IsDir() {
+			return nil
+		}
+		b, err := os.ReadFile(p)
+		if err != nil {
+			return fmt.Errorf("error reading file %q: %w", p, err)
+		}
+
+		m := &moduleInfo{}
+		if err := yaml.Unmarshal(b, m); err != nil {
+			return fmt.Errorf("error parsing %q: %w", p, err)
+		}
+
+		files[p] = m
+		return nil
+	}); err != nil {
+		t.Fatalf("error during walk: %v", err)
+	}
+
+	for f1, m1 := range files {
+		dir := filepath.Dir(f1)
+		for f2, m2 := range files {
+			// Only compare pairs once
+			if f1 >= f2 {
+				continue
+			}
+
+			if filepath.Dir(f2) != dir {
+				continue
+			}
+
+			if m1.License != m2.License {
+				switch f1 {
+				case "modules/github.com/klauspost/compress/v1.11.2.yaml":
+					// license changed after v1.11.2
+				default:
+					t.Errorf("license mismatch: %v=%v, %v=%v", f1, m1.License, f2, m2.License)
+				}
+			}
+
+		}
+	}
+}