feat: add support for multiple licenses

internal/enforcer/enforcer.go

@@ -38,13 +38,6 @@ type PolicyDeclaration struct {
 	Spec interface{} `yaml:"spec"`
 }
 
-// policyMap defines the set of policies allowed within Conform.
-var policyMap = map[string]policy.Policy{
-	"commit":  &commit.Commit{},
-	"license": &license.License{},
-	// "version":    &version.Version{},
-}
-
 // New loads the conform.yaml file and unmarshals it into a Conform struct.
 func New(r string) (*Conform, error) {
 	c := &Conform{}
@@ -84,8 +77,13 @@ func (c *Conform) Enforce(setters ...policy.Option) error {
 
 	pass := true
 
-	for _, p := range c.Policies {
-		report, err := c.enforce(p, opts)
+	policiesWithTypes, err := c.convertDeclarations()
+	if err != nil {
+		return fmt.Errorf("failed to convert declarations: %w", err)
+	}
+
+	for _, p := range policiesWithTypes {
+		report, err := p.policy.Compliance(opts)
 		if err != nil {
 			log.Fatal(err)
 		}
@@ -120,30 +118,61 @@ func (c *Conform) Enforce(setters ...policy.Option) error {
 	return nil
 }
 
-func (c *Conform) enforce(declaration *PolicyDeclaration, opts *policy.Options) (*policy.Report, error) {
-	if _, ok := policyMap[declaration.Type]; !ok {
-		return nil, errors.Errorf("Policy %q is not defined", declaration.Type)
-	}
+type policyWithType struct {
+	policy policy.Policy
+	Type   string
+}
+
+func (c *Conform) convertDeclarations() ([]policyWithType, error) {
+	const typeLicense = "license"
+
+	var (
+		policies = make([]policyWithType, 0, len(c.Policies))
+		licenses = make(license.Licenses, 0, len(c.Policies))
+	)
 
-	p := policyMap[declaration.Type]
+	for _, p := range c.Policies {
+		switch p.Type {
+		case typeLicense:
+			var lcs license.License
+
+			if err := mapstructure.Decode(p.Spec, &lcs); err != nil {
+				return nil, fmt.Errorf("failed to convert license policy: %w", err)
+			}
 
-	// backwards compatibility, convert `gpg: bool` into `gpg: required: bool`
-	if declaration.Type == "commit" {
-		if spec, ok := declaration.Spec.(map[interface{}]interface{}); ok {
-			if gpg, ok := spec["gpg"]; ok {
-				if val, ok := gpg.(bool); ok {
-					spec["gpg"] = map[string]interface{}{
-						"required": val,
+			licenses = append(licenses, lcs)
+
+		case "commit":
+			// backwards compatibility, convert `gpg: bool` into `gpg: required: bool`
+			if spec, ok := p.Spec.(map[interface{}]interface{}); ok {
+				if gpg, ok := spec["gpg"]; ok {
+					if val, ok := gpg.(bool); ok {
+						spec["gpg"] = map[string]interface{}{
+							"required": val,
+						}
 					}
 				}
 			}
+
+			var cmt commit.Commit
+
+			if err := mapstructure.Decode(p.Spec, &cmt); err != nil {
+				return nil, fmt.Errorf("failed to convert commit policy: %w", err)
+			}
+
+			policies = append(policies, policyWithType{
+				Type:   p.Type,
+				policy: &cmt,
+			})
+		default:
+			return nil, fmt.Errorf("invalid policy type: %s", p.Type)
 		}
 	}
 
-	err := mapstructure.Decode(declaration.Spec, p)
-	if err != nil {
-		return nil, errors.Errorf("Internal error: %v", err)
-	}
+	policies = append(policies, policyWithType{
+		Type:   typeLicense,
+		policy: &licenses,
+	})
 
-	return p.Compliance(opts)
+	return policies, nil
 }

internal/policy/license/license.go

@@ -19,11 +19,14 @@ import (
 	"github.com/siderolabs/conform/internal/policy"
 )
 
-// License implements the policy.Policy interface and enforces source code
-// license headers.
+// Licenses implement the policy.Policy interface and enforces source code license headers.
+type Licenses []License
+
+// License represents a single license policy.
 //
 //nolint:govet
 type License struct {
+	Root string `mapstructure:"root"`
 	// SkipPaths applies gitignore-style patterns to file paths to skip completely
 	// parts of the tree which shouldn't be scanned (e.g. .git/)
 	SkipPaths []string `mapstructure:"skipPaths"`
@@ -42,17 +45,17 @@ type License struct {
 }
 
 // Compliance implements the policy.Policy.Compliance function.
-func (l *License) Compliance(_ *policy.Options) (*policy.Report, error) {
+func (l *Licenses) Compliance(_ *policy.Options) (*policy.Report, error) {
 	report := &policy.Report{}
 
-	report.AddCheck(l.ValidateLicenseHeader())
+	report.AddCheck(l.ValidateLicenseHeaders())
 
 	return report, nil
 }
 
 // HeaderCheck enforces a license header on source code files.
 type HeaderCheck struct {
-	errors []error
+	licenseErrors []error
 }
 
 // Name returns the name of the check.
@@ -62,44 +65,58 @@ func (l HeaderCheck) Name() string {
 
 // Message returns to check message.
 func (l HeaderCheck) Message() string {
-	if len(l.errors) != 0 {
-		return fmt.Sprintf("Found %d files without license header", len(l.errors))
+	if len(l.licenseErrors) != 0 {
+		return fmt.Sprintf("Found %d files without license header", len(l.licenseErrors))
 	}
 
 	return "All files have a valid license header"
 }
 
 // Errors returns any violations of the check.
 func (l HeaderCheck) Errors() []error {
-	return l.errors
+	return l.licenseErrors
+}
+
+// ValidateLicenseHeaders checks the header of a file and ensures it contains the provided value.
+func (l Licenses) ValidateLicenseHeaders() policy.Check { //nolint:ireturn
+	check := HeaderCheck{}
+
+	for _, license := range l {
+		if license.Root == "" {
+			license.Root = "."
+		}
+
+		check.licenseErrors = append(check.licenseErrors, validateLicenseHeader(license)...)
+	}
+
+	return check
 }
 
-// ValidateLicenseHeader checks the header of a file and ensures it contains the
-// provided value.
-func (l License) ValidateLicenseHeader() policy.Check { //nolint:gocognit,ireturn
+//nolint:gocognit
+func validateLicenseHeader(license License) []error {
+	var errs []error
+
 	var buf bytes.Buffer
 
-	for _, pattern := range l.SkipPaths {
+	for _, pattern := range license.SkipPaths {
 		fmt.Fprintf(&buf, "%s\n", pattern)
 	}
 
-	check := HeaderCheck{}
-
-	patternmatcher := gitignore.New(&buf, ".", func(e gitignore.Error) bool {
-		check.errors = append(check.errors, e.Underlying())
+	patternmatcher := gitignore.New(&buf, license.Root, func(e gitignore.Error) bool {
+		errs = append(errs, e.Underlying())
 
 		return true
 	})
 
-	if l.Header == "" {
-		check.errors = append(check.errors, errors.New("Header is not defined"))
+	if license.Header == "" {
+		errs = append(errs, errors.New("Header is not defined"))
 
-		return check
+		return errs
 	}
 
-	value := []byte(strings.TrimSpace(l.Header))
+	value := []byte(strings.TrimSpace(license.Header))
 
-	err := filepath.Walk(".", func(path string, info os.FileInfo, err error) error {
+	err := filepath.Walk(license.Root, func(path string, info os.FileInfo, err error) error {
 		if err != nil {
 			return err
 		}
@@ -117,23 +134,23 @@ func (l License) ValidateLicenseHeader() policy.Check { //nolint:gocognit,iretur
 
 		if info.Mode().IsRegular() {
 			// Skip excluded suffixes.
-			for _, suffix := range l.ExcludeSuffixes {
+			for _, suffix := range license.ExcludeSuffixes {
 				if strings.HasSuffix(info.Name(), suffix) {
 					return nil
 				}
 			}
 
 			// Check files matching the included suffixes.
-			for _, suffix := range l.IncludeSuffixes {
+			for _, suffix := range license.IncludeSuffixes {
 				if strings.HasSuffix(info.Name(), suffix) {
-					if l.AllowPrecedingComments {
+					if license.AllowPrecedingComments {
 						err = validateFileWithPrecedingComments(path, value)
 					} else {
 						err = validateFile(path, value)
 					}
 
 					if err != nil {
-						check.errors = append(check.errors, err)
+						errs = append(errs, err)
 					}
 				}
 			}
@@ -142,10 +159,10 @@ func (l License) ValidateLicenseHeader() policy.Check { //nolint:gocognit,iretur
 		return nil
 	})
 	if err != nil {
-		check.errors = append(check.errors, errors.Errorf("Failed to walk directory: %v", err))
+		errs = append(errs, errors.Errorf("Failed to walk directory: %v", err))
 	}
 
-	return check
+	return errs
 }
 
 func validateFile(path string, value []byte) error {

internal/policy/license/license_test.go

@@ -21,23 +21,75 @@ func TestLicense(t *testing.T) {
 // License, v. 2.0. If a copy of the MPL was not distributed with this
 // file, You can obtain one at http://mozilla.org/MPL/2.0/.`
 
+	const otherHeader = "// some-other-header"
+
 	t.Run("Default", func(t *testing.T) {
-		l := license.License{
-			IncludeSuffixes:        []string{".txt"},
-			AllowPrecedingComments: false,
-			Header:                 header,
+		l := license.Licenses{
+			{
+				SkipPaths:              []string{"subdir1/"},
+				IncludeSuffixes:        []string{".txt"},
+				AllowPrecedingComments: false,
+				Header:                 header,
+			},
 		}
-		check := l.ValidateLicenseHeader()
+		check := l.ValidateLicenseHeaders()
 		assert.Equal(t, "Found 1 files without license header", check.Message())
 	})
 
 	t.Run("AllowPrecedingComments", func(t *testing.T) {
-		l := license.License{
-			IncludeSuffixes:        []string{".txt"},
-			AllowPrecedingComments: true,
-			Header:                 header,
+		l := license.Licenses{
+			{
+				SkipPaths:              []string{"subdir1/"},
+				IncludeSuffixes:        []string{".txt"},
+				AllowPrecedingComments: true,
+				Header:                 header,
+			},
+		}
+		check := l.ValidateLicenseHeaders()
+		assert.Equal(t, "All files have a valid license header", check.Message())
+	})
+
+	// File "testdata/subdir1/subdir2/data.txt" is valid for the root license, but "testdata/subdir1/" is skipped.
+	// It is invalid for the additional license, but that license skips "subdir2/" relative to itself.
+	// The check should pass.
+	t.Run("AdditionalValid", func(t *testing.T) {
+		l := license.Licenses{
+			{
+				IncludeSuffixes:        []string{".txt"},
+				SkipPaths:              []string{"testdata/subdir1/"},
+				AllowPrecedingComments: true,
+				Header:                 header,
+			},
+			{
+				Root:            "testdata/subdir1/",
+				SkipPaths:       []string{"subdir2/"},
+				IncludeSuffixes: []string{".txt"},
+				Header:          otherHeader,
+			},
 		}
-		check := l.ValidateLicenseHeader()
+		check := l.ValidateLicenseHeaders()
 		assert.Equal(t, "All files have a valid license header", check.Message())
 	})
+
+	// File "testdata/subdir1/subdir2/data.txt" is valid for the root license, but "testdata/subdir1/" is skipped.
+	// However, it is invalid for the additional license.
+	// The check should fail.
+	t.Run("AdditionalInvalid", func(t *testing.T) {
+		l := license.Licenses{
+			{
+				IncludeSuffixes:        []string{".txt"},
+				SkipPaths:              []string{"testdata/subdir1/"},
+				AllowPrecedingComments: true,
+				Header:                 header,
+			},
+
+			{
+				Root:            "testdata/subdir1/",
+				IncludeSuffixes: []string{".txt"},
+				Header:          otherHeader,
+			},
+		}
+		check := l.ValidateLicenseHeaders()
+		assert.Equal(t, "Found 1 files without license header", check.Message())
+	})
 }

internal/policy/license/testdata/subdir1/data.txt

@@ -0,0 +1,3 @@
+// some-other-header
+
+content

internal/policy/license/testdata/subdir1/subdir2/data.txt

@@ -0,0 +1,5 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+content