Add lint job to CI

.github/workflows/go.yml

@@ -5,6 +5,20 @@ on:
       - master
   pull_request:
 jobs:
+  lint:
+    name: lint
+    runs-on: ubuntu-latest
+    steps:
+      - name: checkout
+        uses: actions/checkout@v4
+      - name: setup Go
+        uses: actions/setup-go@v4
+        with:
+          go-version: "1.23"
+      - name: run linters
+        run: |
+          make lint
+
   race-test:
     name: Test with -race
     strategy:

.gitignore

@@ -0,0 +1 @@
+bin/

.golangci.yml

@@ -0,0 +1,42 @@
+run:
+  timeout: 5m
+
+linters-settings:
+  errcheck:
+    check-type-assertions: true
+  gci:
+    sections:
+      - "standard"
+      - "default"
+      - "prefix(github.com/goccy/go-yaml)"
+      - "blank"
+      - "dot"
+  gofmt:
+    simplify: true
+  govet:
+    disable:
+      - tests
+  misspell:
+    locale: US
+  staticcheck:
+    checks: ["all", "-ST1000", "-ST1005"]
+
+linters:
+  disable-all: true
+  enable:
+    - errcheck
+    - gci
+    - gofmt
+    - gosimple
+    - govet
+    - ineffassign
+    - misspell
+    - staticcheck
+    - typecheck
+    - unused
+
+issues:
+  exclude-rules:
+    - path: _test\.go
+      linters:
+        - staticcheck

Makefile

@@ -17,3 +17,31 @@ cover-html: cover
 .PHONY: ycat/build
 ycat/build:
 	go build -o ycat ./cmd/ycat
+
+.PHONY: lint
+lint: golangci-lint ## Run golangci-lint
+	@$(GOLANGCI_LINT) run
+
+.PHONY: fmt
+fmt: golangci-lint ## Ensure consistent code style
+	@go mod tidy
+	@go fmt ./...
+	@$(GOLANGCI_LINT) run --fix
+
+## Location to install dependencies to
+LOCALBIN ?= $(shell pwd)/bin
+$(LOCALBIN):
+	mkdir -p $(LOCALBIN)
+
+## Tool Binaries
+GOLANGCI_LINT ?= $(LOCALBIN)/golangci-lint
+
+## Tool Versions
+GOLANGCI_VERSION := 1.61.0
+
+.PHONY: golangci-lint
+.PHONY: $(GOLANGCI_LINT)
+golangci-lint: $(GOLANGCI_LINT) ## Download golangci-lint locally if necessary.
+$(GOLANGCI_LINT): $(LOCALBIN)
+	@test -s $(LOCALBIN)/golangci-lint && $(LOCALBIN)/golangci-lint version --format short | grep -q $(GOLANGCI_VERSION) || \
+	curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(LOCALBIN) v$(GOLANGCI_VERSION)

ast/ast.go

@@ -7,8 +7,9 @@ import (
 	"strconv"
 	"strings"
 
-	"github.com/goccy/go-yaml/token"
 	"golang.org/x/xerrors"
+
+	"github.com/goccy/go-yaml/token"
 )
 
 var (
@@ -2092,18 +2093,18 @@ func Merge(dst Node, src Node) error {
 	err := &ErrInvalidMergeType{dst: dst, src: src}
 	switch dst.Type() {
 	case DocumentType:
-		node := dst.(*DocumentNode)
+		node, _ := dst.(*DocumentNode)
 		return Merge(node.Body, src)
 	case MappingType:
-		node := dst.(*MappingNode)
+		node, _ := dst.(*MappingNode)
 		target, ok := src.(*MappingNode)
 		if !ok {
 			return err
 		}
 		node.Merge(target)
 		return nil
 	case SequenceType:
-		node := dst.(*SequenceNode)
+		node, _ := dst.(*SequenceNode)
 		target, ok := src.(*SequenceNode)
 		if !ok {
 			return err

cmd/ycat/ycat.go

@@ -6,10 +6,11 @@ import (
 	"os"
 
 	"github.com/fatih/color"
+	"github.com/mattn/go-colorable"
+
 	"github.com/goccy/go-yaml"
 	"github.com/goccy/go-yaml/lexer"
 	"github.com/goccy/go-yaml/printer"
-	"github.com/mattn/go-colorable"
 )
 
 const escape = "\x1b"
@@ -71,7 +72,7 @@ func _main(args []string) error {
 		}
 	}
 	writer := colorable.NewColorableStdout()
-	writer.Write([]byte(p.PrintTokens(tokens) + "\n"))
+	_, _ = writer.Write([]byte(p.PrintTokens(tokens) + "\n"))
 	return nil
 }
 

decode.go

@@ -100,7 +100,7 @@ func (d *Decoder) castToFloat(v interface{}) interface{} {
 
 func (d *Decoder) mergeValueNode(value ast.Node) ast.Node {
 	if value.Type() == ast.AliasType {
-		aliasNode := value.(*ast.AliasNode)
+		aliasNode, _ := value.(*ast.AliasNode)
 		aliasName := aliasNode.Value.GetToken().Value
 		return d.anchorNodeMap[aliasName]
 	}
@@ -360,7 +360,7 @@ func (d *Decoder) resolveAlias(node ast.Node) (ast.Node, error) {
 			if err != nil {
 				return nil, err
 			}
-			n.Values[idx] = value.(*ast.MappingValueNode)
+			n.Values[idx], _ = value.(*ast.MappingValueNode)
 		}
 	case *ast.TagNode:
 		value, err := d.resolveAlias(n.Value)
@@ -389,7 +389,7 @@ func (d *Decoder) resolveAlias(node ast.Node) (ast.Node, error) {
 			if err != nil {
 				return nil, err
 			}
-			n.Key = key.(ast.MapKeyNode)
+			n.Key, _ = key.(ast.MapKeyNode)
 			value, err := d.resolveAlias(n.Value)
 			if err != nil {
 				return nil, err
@@ -476,15 +476,6 @@ func (d *Decoder) getArrayNode(node ast.Node) (ast.ArrayNode, error) {
 	return arrayNode, nil
 }
 
-func (d *Decoder) fileToNode(f *ast.File) ast.Node {
-	for _, doc := range f.Docs {
-		if v := d.nodeToValue(doc.Body); v != nil {
-			return doc.Body
-		}
-	}
-	return nil
-}
-
 func (d *Decoder) convertValue(v reflect.Value, typ reflect.Type, src ast.Node) (reflect.Value, error) {
 	if typ.Kind() != reflect.String {
 		if !v.Type().ConvertibleTo(typ) {
@@ -590,7 +581,7 @@ func (d *Decoder) deleteStructKeys(structType reflect.Type, unknownFields map[st
 		}
 
 		if structField.IsInline {
-			d.deleteStructKeys(field.Type, unknownFields)
+			_ = d.deleteStructKeys(field.Type, unknownFields)
 		} else {
 			delete(unknownFields, structField.RenderName)
 		}
@@ -1275,7 +1266,7 @@ func (d *Decoder) decodeStruct(ctx context.Context, dst reflect.Value, src ast.N
 				}
 				continue
 			}
-			d.setDefaultValueIfConflicted(newFieldValue, structFieldMap)
+			_ = d.setDefaultValueIfConflicted(newFieldValue, structFieldMap)
 			fieldValue.Set(d.castToAssignableValue(newFieldValue, fieldValue.Type()))
 			continue
 		}
@@ -1623,13 +1614,13 @@ func (d *Decoder) readersUnderDir(dir string) ([]io.Reader, error) {
 
 func (d *Decoder) readersUnderDirRecursive(dir string) ([]io.Reader, error) {
 	readers := []io.Reader{}
-	if err := filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
+	if err := filepath.Walk(dir, func(path string, info os.FileInfo, _ error) error {
 		if !d.isYAMLFile(path) {
 			return nil
 		}
-		reader, err := d.fileToReader(path)
-		if err != nil {
-			return errors.Wrapf(err, "failed to get reader")
+		reader, readerErr := d.fileToReader(path)
+		if readerErr != nil {
+			return errors.Wrapf(readerErr, "failed to get reader")
 		}
 		readers = append(readers, reader)
 		return nil

decode_test.go

@@ -592,11 +592,11 @@ func TestDecoder(t *testing.T) {
 		},
 		{
 			"v: [A,B,C,]",
-			map[string][]string{"v": []string{"A", "B", "C"}},
+			map[string][]string{"v": {"A", "B", "C"}},
 		},
 		{
 			"v: [A,1,C]",
-			map[string][]string{"v": []string{"A", "1", "C"}},
+			map[string][]string{"v": {"A", "1", "C"}},
 		},
 		{
 			"v: [A,1,C]",
@@ -610,11 +610,11 @@ func TestDecoder(t *testing.T) {
 		},
 		{
 			"v:\n - A\n - B\n - C",
-			map[string][]string{"v": []string{"A", "B", "C"}},
+			map[string][]string{"v": {"A", "B", "C"}},
 		},
 		{
 			"v:\n - A\n - 1\n - C",
-			map[string][]string{"v": []string{"A", "1", "C"}},
+			map[string][]string{"v": {"A", "1", "C"}},
 		},
 		{
 			"v:\n - A\n - 1\n - C",
@@ -1470,7 +1470,7 @@ items:
 		if err := dec.Decode(&v); err != nil {
 			t.Fatalf("%+v", err)
 		}
-		items := v.(map[string]interface{})["items"].([]interface{})
+		items, _ := v.(map[string]interface{})["items"].([]interface{})
 		if len(items) != 2 {
 			t.Fatal("failed to decode with merge key")
 		}
@@ -2152,16 +2152,16 @@ func Example_DisallowUnknownField() {
 
 	const src = `---
 simple: string
-complecated: string
+unknown: string
 `
 	err := yaml.NewDecoder(strings.NewReader(src), yaml.DisallowUnknownField()).Decode(&v)
 	fmt.Printf("%v\n", err)
 
 	// OUTPUT:
-	// [3:1] unknown field "complecated"
+	// [3:1] unknown field "unknown"
 	//        1 | ---
 	//        2 | simple: string
-	//     >  3 | complecated: string
+	//     >  3 | unknown: string
 	//            ^
 }
 
@@ -2712,22 +2712,22 @@ func TestDecoder_LiteralWithNewLine(t *testing.T) {
 		LastNode string `yaml:"last"`
 	}
 	tests := []A{
-		A{
+		{
 			Node: "hello\nworld",
 		},
-		A{
+		{
 			Node: "hello\nworld\n",
 		},
-		A{
+		{
 			Node: "hello\nworld\n\n",
 		},
-		A{
+		{
 			LastNode: "hello\nworld",
 		},
-		A{
+		{
 			LastNode: "hello\nworld\n",
 		},
-		A{
+		{
 			LastNode: "hello\nworld\n\n",
 		},
 	}

encode.go

@@ -12,12 +12,13 @@ import (
 	"strings"
 	"time"
 
+	"golang.org/x/xerrors"
+
 	"github.com/goccy/go-yaml/ast"
 	"github.com/goccy/go-yaml/internal/errors"
 	"github.com/goccy/go-yaml/parser"
 	"github.com/goccy/go-yaml/printer"
 	"github.com/goccy/go-yaml/token"
-	"golang.org/x/xerrors"
 )
 
 const (
@@ -93,10 +94,10 @@ func (e *Encoder) EncodeContext(ctx context.Context, v interface{}) error {
 		e.written = true
 	} else {
 		// write document separator
-		e.writer.Write([]byte("---\n"))
+		_, _ = e.writer.Write([]byte("---\n"))
 	}
 	var p printer.Printer
-	e.writer.Write(p.PrintNode(node))
+	_, _ = e.writer.Write(p.PrintNode(node))
 	return nil
 }
 

encode_test.go

@@ -10,10 +10,9 @@ import (
 	"testing"
 	"time"
 
-	"github.com/goccy/go-yaml/parser"
-
 	"github.com/goccy/go-yaml"
 	"github.com/goccy/go-yaml/ast"
+	"github.com/goccy/go-yaml/parser"
 )
 
 var zero = 0
@@ -683,12 +682,12 @@ func TestEncoder(t *testing.T) {
 		// time value
 		{
 			"v: 0001-01-01T00:00:00Z\n",
-			map[string]time.Time{"v": time.Time{}},
+			map[string]time.Time{"v": {}},
 			nil,
 		},
 		{
 			"v: 0001-01-01T00:00:00Z\n",
-			map[string]*time.Time{"v": &time.Time{}},
+			map[string]*time.Time{"v": {}},
 			nil,
 		},
 		{
@@ -1078,7 +1077,7 @@ func TestEncoder_FlowRecursive(t *testing.T) {
 		M map[string][]int `yaml:",flow"`
 	}
 	v.M = map[string][]int{
-		"test": []int{1, 2, 3},
+		"test": {1, 2, 3},
 	}
 	var buf bytes.Buffer
 	if err := yaml.NewEncoder(&buf).Encode(v); err != nil {
@@ -1188,7 +1187,7 @@ func TestEncoder_MarshalAnchor(t *testing.T) {
 	hostIdx := 1
 	opt := yaml.MarshalAnchor(func(anchor *ast.AnchorNode, value interface{}) error {
 		if _, ok := value.(*Host); ok {
-			nameNode := anchor.Name.(*ast.StringNode)
+			nameNode, _ := anchor.Name.(*ast.StringNode)
 			nameNode.Value = fmt.Sprintf("host%d", hostIdx)
 			hostIdx++
 		}