fix(lint): resolve all 49 golangci-lint issues (#262)

* fix(lint): resolve all 49 golangci-lint issues

- Upgrade golangci-lint config to v2 with stricter linters
- Replace interface{} with any and use maps.Copy, strings.SplitSeq
- Use errors.New for static error strings instead of fmt.Errorf
- Use http.StatusOK and http.MethodGet stdlib constants in tests
- Replace os.Chdir/os.Setenv with t.Chdir/t.Setenv in tests
- Add required explanations to all nolint directives
- Replace fmt.Printf with proper error returns in anthropic provider

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix(lint): address PR review feedback

- Wrap original error with %w in anthropic APIError branches
- Add trailing newline to color.White version output
- Quote file path in test shell command with fmt.Sprintf %q

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix(lint): resolve windows-specific lint issues

- Use errors.New for static error strings in api_key_helper_windows.go
- Modernize for loops to range over int in windows test

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: appleboy

.golangci.yml

@@ -1,49 +1,114 @@
 version: "2"
+output:
+  sort-order:
+    - file
 linters:
   default: none
   enable:
+    - bidichk
     - bodyclose
-    - dogsled
-    - dupl
+    - depguard
     - errcheck
-    - exhaustive
-    - goconst
+    - forbidigo
+    - gocheckcompilerdirectives
     - gocritic
-    - gocyclo
-    - goprintffuncname
-    - gosec
     - govet
     - ineffassign
-    - misspell
+    - mirror
+    - modernize
     - nakedret
-    - noctx
+    - nilnil
     - nolintlint
-    - rowserrcheck
+    - perfsprint
+    - revive
     - staticcheck
+    - testifylint
     - unconvert
     - unparam
     - unused
-    - whitespace
+    - usestdlibvars
+    - usetesting
+    - wastedassign
+  settings:
+    depguard:
+      rules:
+        main:
+          deny:
+            - pkg: io/ioutil
+              desc: use os or io instead
+            - pkg: golang.org/x/exp
+              desc: it's experimental and unreliable
+            - pkg: github.com/pkg/errors
+              desc: use builtin errors package instead
+    nolintlint:
+      allow-unused: false
+      require-explanation: true
+      require-specific: true
+    gocritic:
+      enabled-checks:
+        - equalFold
+      disabled-checks: []
+    revive:
+      severity: error
+      rules:
+        - name: blank-imports
+        - name: constant-logical-expr
+        - name: context-as-argument
+        - name: context-keys-type
+        - name: dot-imports
+        - name: empty-lines
+        - name: error-return
+        - name: error-strings
+        - name: exported
+        - name: identical-branches
+        - name: if-return
+        - name: increment-decrement
+        - name: modifies-value-receiver
+        - name: package-comments
+        - name: redefines-builtin-id
+        - name: superfluous-else
+        - name: time-naming
+        - name: unexported-return
+        - name: var-declaration
+        - name: var-naming
+          disabled: true
+    staticcheck:
+      checks:
+        - all
+    testifylint: {}
+    usetesting:
+      os-temp-dir: true
+    perfsprint:
+      concat-loop: false
+    govet:
+      enable:
+        - nilness
+        - unusedwrite
   exclusions:
     generated: lax
     presets:
       - comments
       - common-false-positives
       - legacy
       - std-error-handling
-    paths:
-      - third_party$
-      - builtin$
-      - examples$
+    rules:
+      - linters:
+          - errcheck
+          - staticcheck
+          - unparam
+        path: _test\.go
+issues:
+  max-issues-per-linter: 0
+  max-same-issues: 0
 formatters:
   enable:
     - gofmt
     - gofumpt
-    - goimports
     - golines
+  settings:
+    gofumpt:
+      extra-rules: true
   exclusions:
     generated: lax
-    paths:
-      - third_party$
-      - builtin$
-      - examples$
+run:
+  timeout: 10m

cmd/commit.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"html"
 	"io"
+	"maps"
 	"os"
 	"path"
 	"strings"
@@ -136,9 +137,7 @@ var commitCmd = &cobra.Command{
 		data := util.Data{}
 		// Add template variables
 		if vars := util.ConvertToMap(templateVars); len(vars) > 0 {
-			for k, v := range vars {
-				data[k] = v
-			}
+			maps.Copy(data, vars)
 		}
 
 		// Add template variables from file

cmd/textarea.go

@@ -32,7 +32,7 @@ func initialPrompt(value string) model {
 	ti.InsertString(value)
 
 	maxWidth := 0
-	for _, line := range strings.Split(value, "\n") {
+	for line := range strings.SplitSeq(value, "\n") {
 		if len(line) > maxWidth {
 			maxWidth = len(line)
 		}
@@ -57,7 +57,7 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 
 	switch msg := msg.(type) {
 	case tea.KeyMsg:
-		switch msg.Type { //nolint:exhaustive
+		switch msg.Type { //nolint:exhaustive // only handling specific key types
 		case tea.KeyEsc:
 			if m.textarea.Focused() {
 				m.textarea.Blur()

cmd/version.go

@@ -89,7 +89,7 @@ func printVersion(format string, v VersionInfo) error {
 		// Print each row with colored label and default value color
 		for _, row := range rows {
 			blue.Print(row[0])
-			fmt.Printf(" %s\n", row[1])
+			color.White(" %s\n", row[1])
 		}
 		return nil
 	}

core/transport/transport_test.go

@@ -20,7 +20,7 @@ func (m *mockRoundTripper) RoundTrip(req *http.Request) (*http.Response, error)
 	if m.resp != nil || m.err != nil {
 		return m.resp, m.err
 	}
-	return &http.Response{StatusCode: 200, Body: http.NoBody, Request: req}, nil
+	return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody, Request: req}, nil
 }
 
 func TestDefaultHeaderTransport_CustomHeaders(t *testing.T) {
@@ -34,7 +34,12 @@ func TestDefaultHeaderTransport_CustomHeaders(t *testing.T) {
 		AppName:    "myapp",
 		AppVersion: "1.2.3",
 	}
-	req, _ := http.NewRequestWithContext(context.Background(), "GET", "http://example.com", nil)
+	req, _ := http.NewRequestWithContext(
+		context.Background(),
+		http.MethodGet,
+		"http://example.com",
+		nil,
+	)
 	resp, err := tr.RoundTrip(req)
 	if err != nil {
 		t.Fatalf("RoundTrip error: %v", err)
@@ -65,7 +70,12 @@ func TestDefaultHeaderTransport_EmptyHeadersAndAppInfo(t *testing.T) {
 		AppName:    "",
 		AppVersion: "",
 	}
-	req, _ := http.NewRequestWithContext(context.Background(), "GET", "http://example.com", nil)
+	req, _ := http.NewRequestWithContext(
+		context.Background(),
+		http.MethodGet,
+		"http://example.com",
+		nil,
+	)
 	resp, err := tr.RoundTrip(req)
 	if err != nil {
 		t.Fatalf("RoundTrip error: %v", err)
@@ -91,7 +101,12 @@ func TestDefaultHeaderTransport_OriginErrorPropagation(t *testing.T) {
 		AppName:    "",
 		AppVersion: "",
 	}
-	req, _ := http.NewRequestWithContext(context.Background(), "GET", "http://example.com", nil)
+	req, _ := http.NewRequestWithContext(
+		context.Background(),
+		http.MethodGet,
+		"http://example.com",
+		nil,
+	)
 	resp, err := tr.RoundTrip(req)
 	if resp != nil && resp.Body != nil {
 		resp.Body.Close()
@@ -111,7 +126,12 @@ func TestDefaultHeaderTransport_MultipleHeaderValues(t *testing.T) {
 		AppName:    "app",
 		AppVersion: "v",
 	}
-	req, _ := http.NewRequestWithContext(context.Background(), "GET", "http://example.com", nil)
+	req, _ := http.NewRequestWithContext(
+		context.Background(),
+		http.MethodGet,
+		"http://example.com",
+		nil,
+	)
 	resp, err := tr.RoundTrip(req)
 	if err != nil {
 		t.Fatalf("RoundTrip error: %v", err)

git/git.go

@@ -3,7 +3,6 @@ package git
 import (
 	"context"
 	"errors"
-	"fmt"
 	"os"
 	"os/exec"
 	"path"
@@ -138,7 +137,7 @@ func (c *Command) commit(ctx context.Context, val string) *exec.Cmd {
 		"commit",
 		"--no-verify",
 		"--signoff",
-		fmt.Sprintf("--message=%s", val),
+		"--message=" + val,
 	}
 
 	if c.isAmend {
@@ -234,7 +233,11 @@ func (c *Command) InstallHook(ctx context.Context) error {
 	}
 
 	// Write the hook file with executable permissions (0o755)
-	return os.WriteFile(target, content, 0o755) //nolint:gosec
+	return os.WriteFile(
+		target,
+		content,
+		0o755,
+	) //nolint:gosec // hook file needs executable permissions
 }
 
 // UninstallHook removes the prepare-commit-msg hook if it exists.

git/git_test.go

@@ -25,24 +25,12 @@ func TestCanExecuteGitDiff(t *testing.T) {
 		tmpDir := t.TempDir()
 
 		// Change to the temporary directory
-		originalDir, err := os.Getwd()
-		if err != nil {
-			t.Fatalf("Failed to get current directory: %v", err)
-		}
-		defer func() {
-			if err := os.Chdir(originalDir); err != nil {
-				t.Logf("Failed to restore directory: %v", err)
-			}
-		}()
-
-		if err := os.Chdir(tmpDir); err != nil {
-			t.Fatalf("Failed to change directory: %v", err)
-		}
+		t.Chdir(tmpDir)
 
 		cmd := New()
 		ctx := context.Background()
 
-		err = cmd.CanExecuteGitDiff(ctx)
+		err := cmd.CanExecuteGitDiff(ctx)
 		if err == nil {
 			t.Error("CanExecuteGitDiff() should fail in a non-git directory")
 		}
@@ -63,24 +51,12 @@ func TestCanExecuteGitDiff(t *testing.T) {
 		defer os.RemoveAll(tmpDir)
 
 		// Change to the subdirectory
-		originalDir, err := os.Getwd()
-		if err != nil {
-			t.Fatalf("Failed to get current directory: %v", err)
-		}
-		defer func() {
-			if err := os.Chdir(originalDir); err != nil {
-				t.Logf("Failed to restore directory: %v", err)
-			}
-		}()
-
-		if err := os.Chdir(tmpDir); err != nil {
-			t.Fatalf("Failed to change directory: %v", err)
-		}
+		t.Chdir(tmpDir)
 
 		cmd := New()
 		ctx := context.Background()
 
-		err = cmd.CanExecuteGitDiff(ctx)
+		err := cmd.CanExecuteGitDiff(ctx)
 		if err != nil {
 			t.Errorf(
 				"CanExecuteGitDiff() should succeed in a git repository subdirectory, got error: %v",

git/hook.go

@@ -26,7 +26,7 @@ const (
 
 // init initializes the Git hook templates by loading them from embedded files.
 // If there's an error loading the templates, the function logs a fatal error and terminates the program.
-func init() { //nolint:gochecknoinits
+func init() { //nolint:gochecknoinits // required to load embedded templates at startup
 	if err := util.LoadTemplates(files); err != nil {
 		log.Fatal(err)
 	}

prompt/prompt.go

@@ -23,7 +23,7 @@ const (
 )
 
 // Initializes the prompt package by loading the templates from the embedded file system.
-func init() { //nolint:gochecknoinits
+func init() { //nolint:gochecknoinits // required to load embedded templates at startup
 	if err := util.LoadTemplates(templatesFS); err != nil {
 		log.Fatal(err)
 	}

provider/anthropic/anthropic.go

@@ -42,11 +42,14 @@ func (c *Client) Completion(ctx context.Context, content string) (*core.Response
 	if err != nil {
 		var e *anthropic.APIError
 		if errors.As(err, &e) {
-			fmt.Printf("Messages error, type: %s, message: %s", e.Type, e.Message)
-		} else {
-			fmt.Printf("Messages error: %v\n", err)
+			return nil, fmt.Errorf(
+				"messages error, type: %s, message: %s: %w",
+				e.Type,
+				e.Message,
+				err,
+			)
 		}
-		return nil, err
+		return nil, fmt.Errorf("messages error: %w", err)
 	}
 
 	usage := core.Usage{
@@ -97,11 +100,14 @@ func (c *Client) CompletionStream(
 	if err != nil {
 		var e *anthropic.APIError
 		if errors.As(err, &e) {
-			fmt.Printf("Messages error, type: %s, message: %s", e.Type, e.Message)
-		} else {
-			fmt.Printf("Messages error: %v\n", err)
+			return nil, fmt.Errorf(
+				"messages error, type: %s, message: %s: %w",
+				e.Type,
+				e.Message,
+				err,
+			)
 		}
-		return nil, err
+		return nil, fmt.Errorf("messages error: %w", err)
 	}
 
 	if writeErr != nil {