Skip deprecated functions unless -deprecated is given

.github/workflows/go.yml

@@ -31,7 +31,7 @@ jobs:
 
       - name: Modver
         if: ${{ github.event_name == 'pull_request' }}
-        uses: bobg/modver@v2.12.1
+        uses: bobg/modver@v2.12.2
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           pull_request_url: https://github.com/${{ github.repository }}/pull/${{ github.event.number }}

Readme.md

@@ -3,7 +3,7 @@
 [![Go Reference](https://pkg.go.dev/badge/github.com/bobg/decouple.svg)](https://pkg.go.dev/github.com/bobg/decouple)
 [![Go Report Card](https://goreportcard.com/badge/github.com/bobg/decouple)](https://goreportcard.com/report/github.com/bobg/decouple)
 [![Tests](https://github.com/bobg/decouple/actions/workflows/go.yml/badge.svg)](https://github.com/bobg/decouple/actions/workflows/go.yml)
-[![Coverage Status](https://coveralls.io/repos/github.com/bobg/decouple/badge.svg?branch=main)](https://coveralls.io/github.com/bobg/decouple?branch=main)
+[![Coverage Status](https://coveralls.io/repos/github/bobg/decouple/badge.svg?branch=main)](https://coveralls.io/github/bobg/decouple?branch=main)
 [![Mentioned in Awesome Go](https://awesome.re/mentioned-badge.svg)](https://github.com/avelino/awesome-go)
 
 This is decouple,

cmd/decouple/decouple_test.go

@@ -14,7 +14,7 @@ import (
 
 func TestRunJSON(t *testing.T) {
 	buf := new(bytes.Buffer)
-	if err := run(buf, false, true, []string{"../.."}); err != nil {
+	if err := run2(buf, false, true, false, []string{"../.."}); err != nil {
 		t.Fatal(err)
 	}
 
@@ -34,7 +34,7 @@ func TestRunJSON(t *testing.T) {
 	want := []jtuple{{
 		PackageName: "main",
 		FileName:    "main.go",
-		Line:        106,
+		Line:        113,
 		Column:      6,
 		FuncName:    "showJSON",
 		Params: []jparam{{
@@ -52,7 +52,7 @@ func TestRunJSON(t *testing.T) {
 
 func TestRunPlain(t *testing.T) {
 	buf := new(bytes.Buffer)
-	if err := run(buf, false, false, []string{"../.."}); err != nil {
+	if err := run2(buf, false, false, false, []string{"../.."}); err != nil {
 		t.Fatal(err)
 	}
 

cmd/decouple/main.go

@@ -17,21 +17,27 @@ import (
 )
 
 func main() {
+	if err := run(); err != nil {
+		fmt.Fprintf(os.Stderr, "Error: %s\n", err)
+		os.Exit(1)
+	}
+}
+
+func run() error {
 	var (
-		verbose bool
-		doJSON  bool
+		deprecated bool
+		doJSON     bool
+		verbose    bool
 	)
-	flag.BoolVar(&verbose, "v", false, "verbose")
+	flag.BoolVar(&deprecated, "deprecated", false, "include deprecated functions in the analysis")
 	flag.BoolVar(&doJSON, "json", false, "output in JSON format")
+	flag.BoolVar(&verbose, "v", false, "verbose")
 	flag.Parse()
 
-	if err := run(os.Stdout, verbose, doJSON, flag.Args()); err != nil {
-		fmt.Fprintln(os.Stderr, err)
-		os.Exit(1)
-	}
+	return run2(os.Stdout, deprecated, doJSON, verbose, flag.Args())
 }
 
-func run(w io.Writer, verbose, doJSON bool, args []string) error {
+func run2(w io.Writer, deprecated, doJSON, verbose bool, args []string) error {
 	var dir string
 	switch len(args) {
 	case 0:
@@ -46,6 +52,7 @@ func run(w io.Writer, verbose, doJSON bool, args []string) error {
 	if err != nil {
 		return errors.Wrapf(err, "creating checker for %s", dir)
 	}
+	checker.Deprecated = deprecated
 	checker.Verbose = verbose
 
 	tuples, err := checker.Check()

decouple.go

@@ -21,9 +21,11 @@ const PkgMode = packages.NeedName | packages.NeedFiles | packages.NeedImports |
 // or a single such package,
 // or a function or function parameter in one.
 //
+// Set Deprecated to include deprecated functions in the analysis, which are normally excluded.
 // Set Verbose to true to get (very) verbose debugging output.
 type Checker struct {
-	Verbose bool
+	Deprecated bool
+	Verbose    bool
 
 	pkgs            []*packages.Package
 	namedInterfaces map[*packages.Package]map[string]namedInterfacePair // pkg -> named interface type -> (method map, is alias)
@@ -191,6 +193,10 @@ type MethodMap = map[string]*types.Signature
 // which should be one of the packages contained in the Checker.
 // The result is a map from parameter names eligible for decoupling to MethodMaps.
 func (ch Checker) CheckFunc(pkg *packages.Package, fndecl *ast.FuncDecl) (map[string]MethodMap, error) {
+	if !ch.Deprecated && isDeprecated(fndecl) {
+		return nil, nil
+	}
+
 	result := make(map[string]MethodMap)
 	for _, field := range fndecl.Type.Params.List {
 		for _, name := range field.Names {
@@ -210,6 +216,19 @@ func (ch Checker) CheckFunc(pkg *packages.Package, fndecl *ast.FuncDecl) (map[st
 	return result, nil
 }
 
+func isDeprecated(fndecl *ast.FuncDecl) bool {
+	if fndecl.Doc == nil {
+		return false
+	}
+	pars := strings.Split(fndecl.Doc.Text(), "\n\n")
+	for _, par := range pars {
+		if strings.HasPrefix(par, "Deprecated:") {
+			return true
+		}
+	}
+	return false
+}
+
 // CheckParam checks a single named parameter in a given function declaration,
 // which must apepar in the given package,
 // which should be one of the packages in the Checker.