all: follow golangci-lint rules for linters (#2)

Author: joshuasing

.github/workflows/go.yml

@@ -103,4 +103,4 @@ jobs:
           check-latest: true
 
       - name: "Run golangci-lint"
-        uses: golangci/golangci-lint-action@4696ba8babb6127d732c3c6dde519db15edab9ea # v6.5.1
+        uses: golangci/golangci-lint-action@1481404843c368bc19ca9406f87d6e0fc97bdcfd # v7.0.0

.golangci.yml

@@ -1,16 +1,18 @@
+version: "2"
+run:
+  go: "1.23"
+
 linters:
   enable:
     - "bodyclose"
     - "copyloopvar"
     - "errcheck"
-    - "gci"
-    - "gofumpt"
     - "goheader"
     - "gosec"
-    - "gosimple"
     - "govet"
     - "ineffassign"
     - "nilerr"
+    - "nolintlint"
     - "predeclared"
     - "revive"
     - "staticcheck"
@@ -20,11 +22,15 @@ linters:
     - "unparam"
     - "whitespace"
 
-linters-settings:
-  # Enforces import order in Go source files
-  gci:
-    sections:
-      - "standard"
-      - "default"
-      - "localmodule"
-    custom-order: true
+formatters:
+  enable:
+    - "gci"
+    - "gofumpt"
+  settings:
+    # Enforces import order in Go source files
+    gci:
+      sections:
+        - "standard"
+        - "default"
+        - "localmodule"
+      custom-order: true

analysis.go

@@ -18,6 +18,7 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
+// Package golicenser implements a go/analysis for linting license headers.
 package golicenser
 
 import (
@@ -35,16 +36,23 @@ import (
 const (
 	analyzerName = "golicenser"
 
+	// DefaultMatchHeaderRegexp is the default regexp used to detect license
+	// headers. This will match any header containing "copyright".
 	DefaultMatchHeaderRegexp = "(?i)copyright"
 )
 
 var (
+	// DefaultMaxConcurrent is the default maximum concurrency to use when
+	// analyzing files.
 	DefaultMaxConcurrent = runtime.GOMAXPROCS(0) * 2
-	DefaultExcludes      = []string{
+
+	// DefaultExcludes are the default files to exclude when analyzing.
+	DefaultExcludes = []string{
 		"**/testdata/**", // Exclude testdata directories
 	}
 )
 
+// Config is the golicenser configuration.
 type Config struct {
 	Header HeaderOpts
 
@@ -53,6 +61,7 @@ type Config struct {
 	MatchHeaderRegexp string
 }
 
+// NewAnalyzer creates a golicenser analyzer.
 func NewAnalyzer(cfg Config) (*analysis.Analyzer, error) {
 	a, err := newAnalyzer(cfg)
 	if err != nil {
@@ -68,6 +77,7 @@ func NewAnalyzer(cfg Config) (*analysis.Analyzer, error) {
 	}, nil
 }
 
+// ExcludeMatcherFunc is a function for determining whether to exclude a file.
 type ExcludeMatcherFunc func(filename string) bool
 
 type analyzer struct {
@@ -173,7 +183,10 @@ func (a *analyzer) checkFile(pass *analysis.Pass, file *ast.File) error {
 
 	if header == "" || !a.headerMatcher.MatchString(header) {
 		// License header is missing, generate a new one.
-		header = a.header.Create(filename) + "\n"
+		newHeader, err := a.header.Create(filename)
+		if err != nil {
+			return fmt.Errorf("create %s header: %w", filename, err)
+		}
 		pass.Report(analysis.Diagnostic{
 			Pos:      file.FileStart,
 			Category: analyzerName,
@@ -182,14 +195,18 @@ func (a *analyzer) checkFile(pass *analysis.Pass, file *ast.File) error {
 				Message: "add license header",
 				TextEdits: []analysis.TextEdit{{
 					Pos:     file.FileStart,
-					NewText: []byte(header),
+					NewText: []byte(newHeader + "\n"),
 				}},
 			}},
 		})
 		return nil
 	}
 
-	if newHeader, modified := a.header.Update(filename, header); modified {
+	newHeader, modified, err := a.header.Update(filename, header)
+	if err != nil {
+		return fmt.Errorf("update %s header: %w", filename, err)
+	}
+	if modified {
 		pass.Report(analysis.Diagnostic{
 			Pos:     headerPos,
 			End:     headerEnd,

cmd/golicenser/golicenser.go

@@ -18,13 +18,15 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
+// Package main provides a CLI for running golicenser.
 package main
 
 import (
 	"flag"
 	"log"
 	"os"
 	"strings"
+	"sync"
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/singlechecker"
@@ -50,7 +52,9 @@ var (
 	matchHeaderRegexp   string
 )
 
-func init() {
+var setupFlagsOnce = sync.OnceFunc(setupFlags)
+
+func setupFlags() {
 	flag.StringVar(&template, "tmpl", "", "License header template")
 	flag.StringVar(&templateFile, "tmpl-file", "license_header.txt",
 		"License header template file")
@@ -84,8 +88,11 @@ var analyzer = &analysis.Analyzer{
 	URL:   "https://github.com/joshuasing/golicenser",
 	Flags: flagSet,
 	Run: func(pass *analysis.Pass) (any, error) {
+		setupFlagsOnce()
+
 		var err error
 		if template == "" {
+			//nolint:gosec // Reading user-defined file.
 			b, err := os.ReadFile(templateFile)
 			if err != nil {
 				log.Fatal("read template file: ", err)
@@ -97,6 +104,7 @@ var analyzer = &analysis.Analyzer{
 			}
 		}
 		if matchTemplate == "" && matchTemplateFile != "" {
+			//nolint:gosec // Reading user-defined file.
 			b, err := os.ReadFile(matchTemplateFile)
 			if err != nil {
 				log.Fatal("read match template file: ", err)

go.mod

@@ -1,6 +1,8 @@
 module github.com/joshuasing/golicenser
 
-go 1.24.1
+go 1.23.0
+
+toolchain go1.24.2
 
 require (
 	github.com/bmatcuk/doublestar/v4 v4.8.1

header.go

@@ -186,10 +186,12 @@ func (cs CommentStyle) Render(s string) string {
 	case CommentStyleBlock:
 		return "/*\n" + s + "\n*/\n"
 	default:
-		panic(fmt.Errorf("golicenser: missing comment style render for %q", cs))
+		// Cannot render as a comment.
+		return s
 	}
 }
 
+// Parse parses the comment and returns the uncommented string.
 func (cs CommentStyle) Parse(s string) string {
 	switch cs {
 	case CommentStyleLine:
@@ -208,10 +210,12 @@ func (cs CommentStyle) Parse(s string) string {
 	case CommentStyleBlock:
 		return strings.TrimSuffix(strings.TrimPrefix(s, "/*\n"), "\n*/\n")
 	default:
-		panic(fmt.Errorf("golicenser: missing comment style parse for %q", cs))
+		// Cannot parse as a comment.
+		return s
 	}
 }
 
+// Header is a helper for generating and updating license headers.
 type Header struct {
 	tmpl    *template.Template
 	matcher *regexp.Regexp
@@ -226,6 +230,7 @@ var tmplFuncMap = template.FuncMap{
 	"basename": filepath.Base,
 }
 
+// HeaderOpts are the options for creating a license header.
 type HeaderOpts struct {
 	Template                   string
 	MatchTemplate              string
@@ -237,6 +242,7 @@ type HeaderOpts struct {
 	CommentStyle               CommentStyle
 }
 
+// NewHeader creates a new header with the given options.
 func NewHeader(opts HeaderOpts) (*Header, error) {
 	if opts.Author == "" {
 		return nil, fmt.Errorf("invalid author: %q", opts.Author)
@@ -304,18 +310,22 @@ func NewHeader(opts HeaderOpts) (*Header, error) {
 }
 
 // Create creates a new license header for the file.
-func (h *Header) Create(filename string) string {
-	return h.commentStyle.Render(h.render(filename, timeNow().Format("2006")))
+func (h *Header) Create(filename string) (string, error) {
+	header, err := h.render(filename, timeNow().Format("2006"))
+	if err != nil {
+		return "", fmt.Errorf("render header: %w", err)
+	}
+	return h.commentStyle.Render(header), nil
 }
 
 // Update updates an existing license header if it matches the
-func (h *Header) Update(filename, header string) (string, bool) {
+func (h *Header) Update(filename, header string) (string, bool, error) {
 	if cs, err := detectCommentStyle(header); err == nil {
 		header = cs.Parse(header)
 	}
 	match := h.matcher.FindStringSubmatch(header)
 	if match == nil {
-		return header, false
+		return header, false, nil
 	}
 
 	var year string
@@ -374,12 +384,15 @@ func (h *Header) Update(filename, header string) (string, bool) {
 	if year == "" {
 		year = timeNow().Format("2006")
 	}
-	newHeader := h.render(filename, year)
 
-	return h.commentStyle.Render(newHeader), newHeader != header
+	newHeader, err := h.render(filename, year)
+	if err != nil {
+		return "", false, fmt.Errorf("render header: %w", err)
+	}
+	return h.commentStyle.Render(newHeader), newHeader != header, nil
 }
 
-func (h *Header) render(filename, year string) string {
+func (h *Header) render(filename, year string) (string, error) {
 	// Built-in variables.
 	m := map[string]any{
 		"author":   h.author,
@@ -390,9 +403,9 @@ func (h *Header) render(filename, year string) string {
 
 	var b bytes.Buffer
 	if err := h.tmpl.Execute(&b, m); err != nil {
-		panic(fmt.Errorf("golicenser: execute header template: %w", err))
+		return "", fmt.Errorf("execute template: %w", err)
 	}
-	return b.String()
+	return b.String(), nil
 }
 
 func headerMatcher(tmpl *template.Template, escapeTmpl bool, authorRegexp *regexp.Regexp, variables map[string]any) (*regexp.Regexp, error) {

header_test.go

@@ -215,7 +215,11 @@ func TestHeaderCreate(t *testing.T) {
 			if (err != nil) != tt.wantErr {
 				t.Errorf("NewHeader err = %v, want err %v", err, tt.wantErr)
 			}
-			if got := h.Create(tt.filename); got != tt.want {
+			header, err := h.Create(tt.filename)
+			if err != nil {
+				t.Errorf("h.Create(%q) err = %v, want nil", header, err)
+			}
+			if got := header; got != tt.want {
 				t.Errorf("h.Create(%q) = %q, want %q", tt.filename, got, tt.want)
 			}
 		})
@@ -324,7 +328,10 @@ func TestHeaderUpdate(t *testing.T) {
 			if (err != nil) != tt.wantErr {
 				t.Errorf("NewHeader err = %v, want err %v", err, tt.wantErr)
 			}
-			got, modified := h.Update(tt.filename, tt.existing)
+			got, modified, err := h.Update(tt.filename, tt.existing)
+			if err != nil {
+				t.Errorf("h.Update() err = %v, want nil", err)
+			}
 			if modified != tt.wantModified {
 				t.Errorf("h.Update() modified = %v, want %v",
 					modified, tt.wantModified)