feat: allow comments before the license header

Useful for controller-gen and other code generators.

Signed-off-by: Alexey Palazhchenko <[email protected]>

.conform.yaml

@@ -33,6 +33,7 @@ policies:
     excludeSuffixes:
       - .pb.go
       - .pb.gw.go
+    allowPrecedingComments: true
     header: |
       // 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

README.md

@@ -87,6 +87,7 @@ policies:
         - .ext
       excludeSuffixes:
         - .exclude-ext-prefix.ext
+      allowPrecedingComments: false
       header: |
         This is the contents of a license header.
 ```

cmd/conform/serve.go

@@ -50,8 +50,8 @@ var serveCmd = &cobra.Command{
 
 					return
 				}
-				//nolint: errcheck
-				defer os.RemoveAll(dir)
+
+				defer os.RemoveAll(dir) //nolint:errcheck
 
 				if err = os.MkdirAll(filepath.Join(dir, "github"), 0o700); err != nil {
 					log.Printf("failed to create github directory: %+v\n", err)

go.mod

@@ -1,5 +1,7 @@
 module github.com/talos-systems/conform
 
+go 1.13
+
 require (
 	github.com/danwakefield/fnmatch v0.0.0-20160403171240-cbb64ac3d964 // indirect
 	github.com/deckarep/golang-set v1.7.1 // indirect
@@ -18,11 +20,10 @@ require (
 	github.com/pkg/errors v0.9.1
 	github.com/spf13/cobra v0.0.3
 	github.com/spf13/pflag v1.0.5 // indirect
+	github.com/stretchr/testify v1.7.0
 	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c
 	gonum.org/v1/gonum v0.6.1 // indirect
 	gopkg.in/jdkato/prose.v2 v2.0.0-20180825173540-767a23049b9e
 	gopkg.in/neurosnap/sentences.v1 v1.0.6 // indirect
 	gopkg.in/yaml.v2 v2.3.0
 )
-
-go 1.13

internal/enforcer/enforcer.go

@@ -112,8 +112,7 @@ func (c *Conform) Enforce(setters ...policy.Option) error {
 		}
 	}
 
-	//nolint: errcheck
-	w.Flush()
+	w.Flush() //nolint:errcheck
 
 	if !pass {
 		return errors.New("1 or more policy failed")

internal/policy/commit/check_jira_test.go

@@ -2,7 +2,7 @@
 // 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/.
 
-//nolint: testpackage
+//nolint:testpackage
 package commit
 
 import (

internal/policy/commit/commit_test.go

@@ -2,7 +2,7 @@
 // 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/.
 
-//nolint: testpackage
+//nolint:testpackage
 package commit
 
 import (

internal/policy/license/license.go

@@ -6,6 +6,7 @@
 package license
 
 import (
+	"bufio"
 	"bytes"
 	"fmt"
 	"io/ioutil"
@@ -33,6 +34,10 @@ type License struct {
 	// ExcludeSuffixes is the Suffixes used to find files that the license policy
 	// should not be applied to.
 	ExcludeSuffixes []string `mapstructure:"excludeSuffixes"`
+	// AllowPrecedingComments, when enabled, allows blank lines and `//` and `#` line comments
+	// before the license header. Useful for code generators that put build constraints or
+	// "DO NOT EDIT" lines before the license.
+	AllowPrecedingComments bool `mapstructure:"allowPrecedingComments"`
 	// Header is the contents of the license header.
 	Header string `mapstructure:"header"`
 }
@@ -95,7 +100,7 @@ func (l License) ValidateLicenseHeader() policy.Check {
 		return check
 	}
 
-	value := []byte(l.Header)
+	value := []byte(strings.TrimSpace(l.Header))
 
 	err := filepath.Walk(".", func(path string, info os.FileInfo, err error) error {
 		if err != nil {
@@ -124,18 +129,15 @@ func (l License) ValidateLicenseHeader() policy.Check {
 			// Check files matching the included suffixes.
 			for _, suffix := range l.IncludeSuffixes {
 				if strings.HasSuffix(info.Name(), suffix) {
-					var contents []byte
-					if contents, err = ioutil.ReadFile(path); err != nil {
-						check.errors = append(check.errors, errors.Errorf("Failed to open %s", path))
-
-						return nil //nolint:nilerr
+					if l.AllowPrecedingComments {
+						err = validateFileWithPrecedingComments(path, value)
+					} else {
+						err = validateFile(path, value)
 					}
 
-					if bytes.HasPrefix(contents, value) {
-						continue
+					if err != nil {
+						check.errors = append(check.errors, err)
 					}
-
-					check.errors = append(check.errors, errors.Errorf("File %s does not contain a license header", info.Name()))
 				}
 			}
 		}
@@ -148,3 +150,53 @@ func (l License) ValidateLicenseHeader() policy.Check {
 
 	return check
 }
+
+func validateFile(path string, value []byte) error {
+	contents, err := ioutil.ReadFile(path)
+	if err != nil {
+		return errors.Errorf("Failed to read %s: %s", path, err)
+	}
+
+	if bytes.HasPrefix(contents, value) {
+		return nil
+	}
+
+	return errors.Errorf("File %s does not contain a license header", path)
+}
+
+func validateFileWithPrecedingComments(path string, value []byte) error {
+	f, err := os.Open(path)
+	if err != nil {
+		return errors.Errorf("Failed to open %s: %s", path, err)
+	}
+	defer f.Close() //nolint:errcheck
+
+	var contents []byte
+
+	// read lines until the first non-comment line
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+
+		comment := line == ""
+		comment = comment || strings.HasPrefix(line, "//")
+		comment = comment || strings.HasPrefix(line, "#")
+
+		if !comment {
+			break
+		}
+
+		contents = append(contents, scanner.Bytes()...)
+		contents = append(contents, '\n')
+	}
+
+	if err := scanner.Err(); err != nil {
+		return errors.Errorf("Failed to check file %s: %s", path, err)
+	}
+
+	if bytes.Contains(contents, value) {
+		return nil
+	}
+
+	return errors.Errorf("File %s does not contain a license header", path)
+}

internal/policy/license/license_test.go

@@ -0,0 +1,43 @@
+//go:build !some_test_tag
+// +build !some_test_tag
+
+// 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/.
+
+package license_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/talos-systems/conform/internal/policy/license"
+)
+
+func TestLicense(t *testing.T) {
+	const header = `
+// 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/.`
+
+	t.Run("Default", func(t *testing.T) {
+		l := license.License{
+			IncludeSuffixes:        []string{".go"},
+			AllowPrecedingComments: false,
+			Header:                 header,
+		}
+		check := l.ValidateLicenseHeader()
+		assert.Equal(t, "Found 1 files without license header", check.Message())
+	})
+
+	t.Run("AllowPrecedingComments", func(t *testing.T) {
+		l := license.License{
+			IncludeSuffixes:        []string{".go"},
+			AllowPrecedingComments: true,
+			Header:                 header,
+		}
+		check := l.ValidateLicenseHeader()
+		assert.Equal(t, "All files have a valid license header", check.Message())
+	})
+}