Upgrade dependency to Go 1.22; add check for errors.As and basic chec…

…k for ZST pointer receivers

Signed-off-by: Oliver Eikemeier <[email protected]>

.codeclimate.yml

@@ -5,6 +5,8 @@ checks:
     enabled: false
   identical-code:
     enabled: false
+  return-statements:
+    enabled: false
 exclude_patterns:
   - "**/.*"
   - "**/*_test.go"

.github/workflows/test.yml

@@ -18,7 +18,7 @@ jobs:
     runs-on: ubuntu-24.04
     strategy:
       matrix:
-        go: ["1.23", "1.22", "1.21"]
+        go: ["1.23", "1.22"]
     env:
       GOTOOLCHAIN: local
     steps:
@@ -32,7 +32,7 @@ jobs:
       - name: 🧸 golangci-lint
         uses: golangci/golangci-lint-action@v6
         with:
-          version: v1.60.1
+          version: v1.60.3
       - name: 🔨 Test
         run: |
           go get -C ./pkg/analyzer/testdata golang.org/x/exp/errors

.golangci.yaml

@@ -6,6 +6,7 @@ linters:
   disable:
     # deprecated
     - execinquery
+    - exportloopref
     - gomnd
     # disabled
     - depguard
@@ -16,9 +17,6 @@ linters:
     - varnamelen
     - wrapcheck
     - wsl
-    # Go 1.22
-    - copyloopvar
-    - intrange
 linters-settings:
   govet:
     enable-all: true

.prettierrc.yaml

@@ -7,3 +7,9 @@ overrides:
   - files: "*.md"
     options:
       tabWidth: 2
+  - files: "*.yaml"
+    options:
+      tabWidth: 2
+  - files: "*.yml"
+    options:
+      tabWidth: 2

README.md

@@ -7,7 +7,7 @@
 [![Go Report Card](https://goreportcard.com/badge/fillmore-labs.com/zerolint)](https://goreportcard.com/report/fillmore-labs.com/zerolint)
 [![License](https://img.shields.io/github/license/fillmore-labs/zerolint)](https://www.apache.org/licenses/LICENSE-2.0)
 
-The `zerolint` linter checks usage patterns of pointers to zero-sized variables in Go.
+The `zerolint` linter checks usage patterns of pointers to zero-size variables in Go.
 
 ## Usage
 

go.mod

@@ -1,6 +1,6 @@
 module fillmore-labs.com/zerolint
 
-go 1.21
+go 1.22
 
 toolchain go1.23.0
 

pkg/analyzer/analyzer.go

@@ -27,7 +27,7 @@ const (
 	Doc  = `checks for usage of pointers to zero-length variables
 	
 Pointer to zero-length variables carry very little information and
-can be avoided in most cases.`
+can often be avoided.`
 )
 
 var Analyzer = &analysis.Analyzer{ //nolint:gochecknoglobals
@@ -44,19 +44,29 @@ func init() { //nolint:gochecknoinits
 }
 
 var (
+	// Excludes is a list of types to exclude from the analysis.
+	Excludes string //nolint:gochecknoglobals
+
+	// ZeroTrace enables tracing of found zero-sized types.
 	ZeroTrace bool //nolint:gochecknoglobals
-	Basic     bool //nolint:gochecknoglobals
+
+	// Basic enables basic analysis only.
+	Basic bool //nolint:gochecknoglobals
 )
 
+// Run applies the analyzer to a package.
 func run(pass *analysis.Pass) (any, error) {
-	excludes, err := ReadExcludes()
+	// Read the list of excluded types from the file specified by the "excluded" flag.
+	excludes, err := ReadExcludes(Excludes)
 	if err != nil {
 		return nil, err
 	}
 
-	v := visitor.Visitor{
-		Pass:      pass,
-		Excludes:  excludes,
+	v := visitor.Run{
+		Visitor: visitor.Visitor{
+			Pass:     pass,
+			Excludes: excludes,
+		},
 		ZeroTrace: ZeroTrace,
 		Basic:     Basic,
 	}

pkg/analyzer/excludes.go

@@ -19,18 +19,19 @@ package analyzer
 import (
 	"bufio"
 	"os"
-)
 
-var Excludes string //nolint:gochecknoglobals
+	"fillmore-labs.com/zerolint/pkg/set"
+)
 
-func ReadExcludes() (map[string]struct{}, error) {
-	excludes := make(map[string]struct{})
+// ReadExcludes reads zero-sized types excluded from analysis from a file and returns them as a set.
+func ReadExcludes(name string) (set.Set[string], error) {
+	excludes := set.New[string]()
 
 	if Excludes == "" {
 		return excludes, nil
 	}
 
-	file, err := os.Open(Excludes)
+	file, err := os.Open(name)
 	if err != nil {
 		return nil, err
 	}
@@ -42,7 +43,7 @@ func ReadExcludes() (map[string]struct{}, error) {
 		if len(expr) == 0 || expr[0] == '#' {
 			continue
 		}
-		excludes[string(expr)] = struct{}{}
+		excludes.Insert(string(expr))
 	}
 	if err2 := scanner.Err(); err2 != nil {
 		return nil, err2

pkg/analyzer/testdata/a/testdata.go

@@ -29,14 +29,14 @@ type typedError[T any] struct {
 	_ [0]T
 }
 
-func (*typedError[_]) Error() string { // want "pointer to zero-size type"
+func (*typedError[_]) Error() string { // want "pointer to zero-sized type"
 	return "an error"
 }
 
 var (
 	_      error = &typedError[any]{}         // want "address of zero-size variable"
 	ErrOne       = &(typedError[int]{})       // want "address of zero-size variable"
-	ErrTwo       = (new)(typedError[float64]) // want "new called on zero-size type"
+	ErrTwo       = (new)(typedError[float64]) // want "new called on zero-sized type"
 )
 
 type myErrors struct{}
@@ -55,6 +55,11 @@ func Exported() {
 		fmt.Println("nil")
 	}
 
+	var oneErr *typedError[int] // want "pointer to zero-sized type"
+	if errors.As(ErrOne, &oneErr) {
+		fmt.Println("ErrOne is typedError[int]")
+	}
+
 	func() {
 		errors := myErrs
 		if errors.Is(ErrOne, ErrTwo) {
@@ -68,12 +73,12 @@ func Exported() {
 		fmt.Println("equal")
 	}
 
-	var err *typedError[int] // want "pointer to zero-size type"
+	var err *typedError[int] // want "pointer to zero-sized type"
 	_ = errors.As(ErrOne, &err)
 
-	_ = (new)(struct{}) // want "new called on zero-size type"
+	_ = (new)(struct{}) // want "new called on zero-sized type"
 
-	_ = new(empty) // want "new called on zero-size type"
+	_ = new(empty) // want "new called on zero-sized type"
 
 	xp, yp := &x, &y // want "address of zero-size variable" "address of zero-size variable"
 
@@ -87,14 +92,10 @@ func Exported() {
 		fmt.Println("not equal")
 	}
 
-	if xp == nil {
-		fmt.Println("nil")
-	}
-
-	_, _ = any(xp).((*[0]string)) // want "pointer to zero-size type"
+	_, _ = any(xp).((*[0]string)) // want "pointer to zero-sized type"
 
 	switch any(xp).(type) {
-	case (*[0]string): // want "pointer to zero-size type"
+	case (*[0]string): // want "pointer to zero-sized type"
 	case string:
 	}
 }
@@ -113,15 +114,15 @@ type A [0]string
 
 type B = A
 
-func (*B) Combine(_ *B) *B { // want "pointer to zero-size type" "pointer to zero-size type" "pointer to zero-size type"
+func (*B) Combine(_ *B) *B { // want "pointer to zero-sized type" "pointer to zero-sized type" "pointer to zero-sized type"
 	return &B{} // want "address of zero-size variable"
 }
 
 func Ptr[T any](v T) *T { return &v }
 
 type greeter [5][5]struct{}
 
-type greeterAlias = *greeter // want "pointer to zero-size type"
+type greeterAlias = *greeter // want "pointer to zero-sized type"
 
 func (g greeterAlias) String() string {
 	return "hello, world"
@@ -131,11 +132,11 @@ var _ fmt.Stringer = &greeter{} // want "address of zero-size variable"
 
 var _ fmt.Stringer = (*greeter)(nil) // want "cast of nil to pointer to zero-size variable"
 
-var _ fmt.Stringer = new(greeter) // want "new called on zero-size type"
+var _ fmt.Stringer = new(greeter) // want "new called on zero-sized type"
 
 type greeter2[T any] [5][5][0]T
 
-func (g *greeter2[T]) String() string { // want "pointer to zero-size type"
+func (g *greeter2[T]) String() string { // want "pointer to zero-sized type"
 	return "hello, world"
 }
 

pkg/analyzer/testdata/a/testdata.go.golden

@@ -29,14 +29,14 @@ type typedError[T any] struct {
 	_ [0]T
 }
 
-func (typedError[_]) Error() string { // want "pointer to zero-size type"
+func (typedError[_]) Error() string { // want "pointer to zero-sized type"
 	return "an error"
 }
 
 var (
 	_      error = typedError[any]{}     // want "address of zero-size variable"
 	ErrOne       = (typedError[int]{})   // want "address of zero-size variable"
-	ErrTwo       = typedError[float64]{} // want "new called on zero-size type"
+	ErrTwo       = typedError[float64]{} // want "new called on zero-sized type"
 )
 
 type myErrors struct{}
@@ -55,6 +55,11 @@ func Exported() {
 		fmt.Println("nil")
 	}
 
+	var oneErr typedError[int] // want "pointer to zero-sized type"
+	if errors.As(ErrOne, &oneErr) {
+		fmt.Println("ErrOne is typedError[int]")
+	}
+
 	func() {
 		errors := myErrs
 		if errors.Is(ErrOne, ErrTwo) {
@@ -68,12 +73,12 @@ func Exported() {
 		fmt.Println("equal")
 	}
 
-	var err typedError[int] // want "pointer to zero-size type"
+	var err typedError[int] // want "pointer to zero-sized type"
 	_ = errors.As(ErrOne, &err)
 
-	_ = struct{}{} // want "new called on zero-size type"
+	_ = struct{}{} // want "new called on zero-sized type"
 
-	_ = empty{} // want "new called on zero-size type"
+	_ = empty{} // want "new called on zero-sized type"
 
 	xp, yp := x, y // want "address of zero-size variable" "address of zero-size variable"
 
@@ -87,14 +92,10 @@ func Exported() {
 		fmt.Println("not equal")
 	}
 
-	if xp == nil {
-		fmt.Println("nil")
-	}
-
-	_, _ = any(xp).(([0]string)) // want "pointer to zero-size type"
+	_, _ = any(xp).(([0]string)) // want "pointer to zero-sized type"
 
 	switch any(xp).(type) {
-	case ([0]string): // want "pointer to zero-size type"
+	case ([0]string): // want "pointer to zero-sized type"
 	case string:
 	}
 }
@@ -113,15 +114,15 @@ type A [0]string
 
 type B = A
 
-func (B) Combine(_ B) B { // want "pointer to zero-size type" "pointer to zero-size type" "pointer to zero-size type"
+func (B) Combine(_ B) B { // want "pointer to zero-sized type" "pointer to zero-sized type" "pointer to zero-sized type"
 	return B{} // want "address of zero-size variable"
 }
 
 func Ptr[T any](v T) *T { return &v }
 
 type greeter [5][5]struct{}
 
-type greeterAlias = greeter // want "pointer to zero-size type"
+type greeterAlias = greeter // want "pointer to zero-sized type"
 
 func (g greeterAlias) String() string {
 	return "hello, world"
@@ -131,11 +132,11 @@ var _ fmt.Stringer = greeter{} // want "address of zero-size variable"
 
 var _ fmt.Stringer = greeter{} // want "cast of nil to pointer to zero-size variable"
 
-var _ fmt.Stringer = greeter{} // want "new called on zero-size type"
+var _ fmt.Stringer = greeter{} // want "new called on zero-sized type"
 
 type greeter2[T any] [5][5][0]T
 
-func (g greeter2[T]) String() string { // want "pointer to zero-size type"
+func (g greeter2[T]) String() string { // want "pointer to zero-sized type"
 	return "hello, world"
 }
 

pkg/analyzer/testdata/basic/testdata.go

@@ -21,15 +21,15 @@ import (
 	"fmt"
 )
 
-type nyError struct{}
+type myError struct{}
 
-func (*nyError) Error() string {
+func (*myError) Error() string { // want "method receiver is pointer to zero-size variable"
 	return "my error"
 }
 
 var (
-	ErrOne = &nyError{}
-	ErrTwo = new(nyError)
+	ErrOne = &myError{}
+	ErrTwo = new(myError)
 )
 
 func Exported() {
@@ -43,7 +43,7 @@ func Exported() {
 		fmt.Println("equal")
 	}
 
-	var err *nyError
+	var err *myError
 	_ = errors.As(ErrOne, &err)
 
 	if ErrOne == ErrTwo { // want "comparison of pointers to zero-size variables"
@@ -54,3 +54,11 @@ func Exported() {
 		fmt.Println("not equal")
 	}
 }
+
+type D struct{ _ int }
+
+func (*D) String() string {
+	return "hello, world"
+}
+
+var _ fmt.Stringer = (*D)(nil)

pkg/analyzer/testdata/go.mod

@@ -1,5 +1,5 @@
 module go.test
 
-go 1.21
+go 1.22
 
-require golang.org/x/exp/errors v0.0.0-20240719175910-8a7402abbf56
+require golang.org/x/exp/errors v0.0.0-20240823005443-9b4947da3948

pkg/analyzer/testdata/go.sum

@@ -1,2 +1,2 @@
-golang.org/x/exp/errors v0.0.0-20240719175910-8a7402abbf56 h1:wWtjcEP22Momq1fphl8WkZCnFX615H/yPDX494o7PtU=
-golang.org/x/exp/errors v0.0.0-20240719175910-8a7402abbf56/go.mod h1:YgqsNsAu4fTvlab/7uiYK9LJrCIzKg/NiZUIH1/ayqo=
+golang.org/x/exp/errors v0.0.0-20240823005443-9b4947da3948 h1:IE9ZGXGK0A3EhE/vajvqwjYT5JsrZfxtVwBflW/O2vU=
+golang.org/x/exp/errors v0.0.0-20240823005443-9b4947da3948/go.mod h1:YgqsNsAu4fTvlab/7uiYK9LJrCIzKg/NiZUIH1/ayqo=