chore(ci): introduce golangci-lint and resolve findings

.github/workflows/ci.yml

@@ -34,8 +34,10 @@ jobs:
       - name: Setup Go environment
         uses: ./.github/actions/setup
 
-      - name: Check gofumpt
-        run: test -z "$(go tool gofumpt -l .)"
+      - name: Run gostyle
+        uses: k1LoW/gostyle-action@e1b847d37b3041c5fdb8b911bcf00b350779ca61 # v1.5.1
 
-      - name: Run go vet
-        run: go vet -all -vettool=$(go tool -n csvppvet) ./...
+      - name: Run golangci-lint
+        uses: golangci/golangci-lint-action@1e7e51e771db61008b38414a730f564565cf7c20 # v9.2.0
+        with:
+          version: v2.9.0

.golangci.yml

@@ -0,0 +1,58 @@
+version: "2"
+
+linters:
+  enable:
+    # Defaults
+    - govet
+    - staticcheck
+    - errcheck
+    - ineffassign
+    - unused
+    # Additional
+    - gosec
+    - bidichk
+    - errorlint
+    - bodyclose
+    - unconvert
+    - usestdlibvars
+    - modernize
+    - exhaustive
+  exclusions:
+    rules:
+      - path: _test\.go
+        linters:
+          - errcheck
+          - gosec
+          - unused
+  settings:
+    staticcheck:
+      checks:
+        - "all"
+        - "-ST1000"
+    errcheck:
+      check-type-assertions: true
+      check-blank: true
+    unused:
+      parameters-are-used: false
+    exhaustive:
+      default-signifies-exhaustive: true
+    gosec:
+      excludes:
+        - G304
+
+formatters:
+  enable:
+    - gofumpt
+    - goimports
+  settings:
+    goimports:
+      local-prefixes:
+        - github.com/osamingo/go-csvpp
+
+run:
+  timeout: 5m
+  modules-download-mode: readonly
+
+issues:
+  max-issues-per-linter: 0
+  max-same-issues: 0

cmd/csvpp/convert.go

@@ -54,7 +54,7 @@ func init() {
 	rootCmd.AddCommand(convertCmd)
 }
 
-func runConvert(cmd *cobra.Command, _ []string) (retErr error) {
+func runConvert(cmd *cobra.Command, _ []string) (retErr error) { //nolint:unused // cobra handler signature
 	// Get flag values
 	inputFile, err := cmd.Flags().GetString("input")
 	if err != nil {
@@ -105,7 +105,11 @@ func runConvert(cmd *cobra.Command, _ []string) (retErr error) {
 	if err != nil {
 		return err
 	}
-	defer r.Close()
+	defer func() {
+		if cerr := r.Close(); cerr != nil && retErr == nil {
+			retErr = fmt.Errorf("failed to close input: %w", cerr)
+		}
+	}()
 
 	// Open output
 	w, err := fileutil.OpenOutput(outputFile, cmd.OutOrStdout())

cmd/csvpp/internal/tui/model.go

@@ -28,9 +28,9 @@ func parseFilterQuery(s string) filterQuery {
 		return filterQuery{}
 	}
 
-	if idx := strings.Index(s, ":"); idx >= 0 {
-		col := strings.TrimSpace(s[:idx])
-		val := strings.TrimSpace(s[idx+1:])
+	if before, after, ok := strings.Cut(s, ":"); ok {
+		col := strings.TrimSpace(before)
+		val := strings.TrimSpace(after)
 		if col != "" {
 			return filterQuery{
 				column: strings.ToLower(col),
@@ -224,16 +224,16 @@ func (m Model) updateFilterMode(msg tea.KeyMsg) (tea.Model, tea.Cmd) { //nostyle
 		m.table.Focus()
 		m.clearFilter()
 		return m, nil
-	}
-
-	// Forward key to textinput
-	var cmd tea.Cmd
-	m.filterInput, cmd = m.filterInput.Update(msg)
+	default:
+		// Forward key to textinput
+		var cmd tea.Cmd
+		m.filterInput, cmd = m.filterInput.Update(msg)
 
-	// Real-time filtering
-	m.applyFilter()
+		// Real-time filtering
+		m.applyFilter()
 
-	return m, cmd
+		return m, cmd
+	}
 }
 
 // updateNormalMode handles key events in normal navigation mode.

cmd/csvpp/validate.go

@@ -23,12 +23,16 @@ func init() {
 	rootCmd.AddCommand(validateCmd)
 }
 
-func runValidate(cmd *cobra.Command, args []string) error {
+func runValidate(cmd *cobra.Command, args []string) (retErr error) {
 	r, err := fileutil.OpenInputFromArgs(args)
 	if err != nil {
 		return err
 	}
-	defer r.Close()
+	defer func() {
+		if cerr := r.Close(); cerr != nil && retErr == nil {
+			retErr = fmt.Errorf("failed to close input: %w", cerr)
+		}
+	}()
 
 	reader := csvpp.NewReader(r)
 
@@ -50,6 +54,6 @@ func runValidate(cmd *cobra.Command, args []string) error {
 		recordCount++
 	}
 
-	fmt.Fprintf(cmd.OutOrStdout(), "Valid CSV++ file with %d record(s)\n", recordCount)
+	fmt.Fprintf(cmd.OutOrStdout(), "Valid CSV++ file with %d record(s)\n", recordCount) //nolint:errcheck // stdout write error is not actionable
 	return nil
 }

cmd/csvpp/view.go

@@ -28,12 +28,16 @@ func init() {
 	rootCmd.AddCommand(viewCmd)
 }
 
-func runView(cmd *cobra.Command, args []string) error {
+func runView(cmd *cobra.Command, args []string) (retErr error) {
 	r, err := fileutil.OpenInputFromArgs(args)
 	if err != nil {
 		return err
 	}
-	defer r.Close()
+	defer func() {
+		if cerr := r.Close(); cerr != nil && retErr == nil {
+			retErr = fmt.Errorf("failed to close input: %w", cerr)
+		}
+	}()
 
 	reader := csvpp.NewReader(r)
 
@@ -50,7 +54,7 @@ func runView(cmd *cobra.Command, args []string) error {
 	// Check if stdout is a terminal
 	if !term.IsTerminal(int(os.Stdout.Fd())) {
 		// Plain text output for pipes
-		fmt.Fprint(cmd.OutOrStdout(), tui.PlainView(headers, records))
+		fmt.Fprint(cmd.OutOrStdout(), tui.PlainView(headers, records)) //nolint:errcheck // stdout write error is not actionable
 		return nil
 	}
 

csvpp_test.go

@@ -118,7 +118,7 @@ func TestParseError_Unwrap(t *testing.T) {
 		t.Parallel()
 
 		got := parseErr.Unwrap()
-		if got != originalErr {
+		if !errors.Is(got, originalErr) {
 			t.Errorf("ParseError.Unwrap() = %v, want %v", got, originalErr)
 		}
 	})

csvpputil/convert.go

@@ -2,6 +2,7 @@ package csvpputil
 
 import (
 	"github.com/goccy/go-yaml"
+
 	"github.com/osamingo/go-csvpp"
 )
 

csvpputil/json_array_writer.go

@@ -15,8 +15,8 @@ type JSONArrayWriterOption func(*JSONArrayWriter)
 // Output order is always determined by the headers order.
 //
 // Deprecated: This option is no longer needed as output order follows headers order.
-func WithDeterministic(_ bool) JSONArrayWriterOption {
-	return func(_ *JSONArrayWriter) {}
+func WithDeterministic(_ bool) JSONArrayWriterOption { //nolint:unused // kept for API compatibility
+	return func(_ *JSONArrayWriter) {} //nolint:unused // kept for API compatibility
 }
 
 // JSONArrayWriter writes CSV++ records as a JSON array using streaming output.

csvpputil/json_array_writer_test.go

@@ -3,6 +3,7 @@ package csvpputil_test
 import (
 	"bytes"
 	"encoding/json/v2"
+	"errors"
 	"io"
 	"testing"
 
@@ -112,7 +113,7 @@ func TestJSONArrayWriter_Write(t *testing.T) {
 		}
 
 		err := w.Write([]*csvpp.Field{{Value: "Alice"}})
-		if err != io.ErrClosedPipe {
+		if !errors.Is(err, io.ErrClosedPipe) {
 			t.Errorf("Write() error = %v, want %v", err, io.ErrClosedPipe)
 		}
 	})

csvpputil/yaml_array_writer.go

@@ -5,6 +5,7 @@ import (
 	"io"
 
 	"github.com/goccy/go-yaml"
+
 	"github.com/osamingo/go-csvpp"
 )
 

csvpputil/yaml_array_writer_test.go

@@ -2,6 +2,7 @@ package csvpputil_test
 
 import (
 	"bytes"
+	"errors"
 	"io"
 	"testing"
 
@@ -97,7 +98,7 @@ func TestYAMLArrayWriter_Write(t *testing.T) {
 		}
 
 		err := w.Write([]*csvpp.Field{{Value: "Alice"}})
-		if err != io.ErrClosedPipe {
+		if !errors.Is(err, io.ErrClosedPipe) {
 			t.Errorf("Write() error = %v, want %v", err, io.ErrClosedPipe)
 		}
 	})

example_test.go

@@ -2,6 +2,7 @@ package csvpp_test
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"io"
 	"log"
@@ -29,7 +30,7 @@ Bob,555-9999,40.7128^-74.0060
 	// Read all records
 	for {
 		record, err := reader.Read()
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			break
 		}
 		if err != nil {
@@ -82,7 +83,7 @@ Bob,77~82
 
 	for {
 		record, err := reader.Read()
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			break
 		}
 		if err != nil {