Fix golangci-lint configuration and resolve all linter errors

- Update .golangci.yml for v2 compatibility
- Add build ignore tags to test fixture files
- Fix 10 errcheck errors (unchecked os.Mkdir, os.Chmod, os.WriteFile)
- Fix 5 staticcheck errors (deprecated rand.Seed, unnecessary fmt.Sprintf)
- All tests pass, 0 linter issues

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: hegner123

.golangci.yml

@@ -1,18 +1,15 @@
-linters:
-  enable:
-    - gofmt
-    - govet
-    - errcheck
-    - staticcheck
-    - unused
-    - gosimple
-    - ineffassign
-    - typecheck
+version: 2
 
 linters-settings:
   errcheck:
     check-blank: true
 
+linters:
+  exclusions:
+    paths:
+      - "test_files/"
+      - "trash/"
+
 issues:
   exclude-use-default: false
   max-issues-per-linter: 0

main_concurrency_test.go

@@ -25,7 +25,7 @@ func TestReplaceInFile_Concurrent(t *testing.T) {
 	numFiles := 100
 	filePaths := make([]string, numFiles)
 	for i := 0; i < numFiles; i++ {
-		content := fmt.Sprintf("Line 1 contains target\nLine 2 has target\nLine 3 target here\n")
+		content := "Line 1 contains target\nLine 2 has target\nLine 3 target here\n"
 		filePaths[i] = createTestFile(t, tmpDir, fmt.Sprintf("file%03d.txt", i), content)
 	}
 
@@ -135,7 +135,9 @@ func TestReplaceInDirectories_ParallelDirectories(t *testing.T) {
 	dirs := make([]string, numDirs)
 	for i := 0; i < numDirs; i++ {
 		dir := filepath.Join(tmpDir, fmt.Sprintf("dir%03d", i))
-		os.Mkdir(dir, 0755)
+		if err := os.Mkdir(dir, 0755); err != nil {
+			t.Fatal(err)
+		}
 		dirs[i] = dir
 
 		// Create files in each directory
@@ -537,7 +539,9 @@ func TestReplaceInDirectories_ConcurrentDirs(t *testing.T) {
 	dirs := make([]string, numDirs)
 	for i := 0; i < numDirs; i++ {
 		dir := filepath.Join(tmpDir, fmt.Sprintf("dir%02d", i))
-		os.Mkdir(dir, 0755)
+		if err := os.Mkdir(dir, 0755); err != nil {
+			t.Fatal(err)
+		}
 		dirs[i] = dir
 
 		for j := 0; j < 50; j++ {

main_failure_test.go

@@ -36,7 +36,7 @@ func TestReplaceInFile_ReadOnlyFile(t *testing.T) {
 	if err := os.Chmod(filePath, 0444); err != nil {
 		t.Fatalf("Failed to chmod: %v", err)
 	}
-	defer os.Chmod(filePath, 0644) // Restore permissions for cleanup
+	defer func() { _ = os.Chmod(filePath, 0644) }() // Restore permissions for cleanup
 
 	config := Config{
 		Search:  "target",
@@ -61,7 +61,7 @@ func TestReplaceInFile_DryRunReadOnly(t *testing.T) {
 	if err := os.Chmod(filePath, 0444); err != nil {
 		t.Fatalf("Failed to chmod: %v", err)
 	}
-	defer os.Chmod(filePath, 0644)
+	defer func() { _ = os.Chmod(filePath, 0644) }()
 
 	config := Config{
 		Search:  "target",
@@ -152,7 +152,7 @@ func TestReplaceInDirectory_NoReadPermission(t *testing.T) {
 	if err := os.Chmod(subDir, 0000); err != nil {
 		t.Fatalf("Failed to chmod: %v", err)
 	}
-	defer os.Chmod(subDir, 0755) // Restore for cleanup
+	defer func() { _ = os.Chmod(subDir, 0755) }() // Restore for cleanup
 
 	config := Config{
 		Search:  "test",
@@ -226,7 +226,7 @@ func TestReplaceInFile_ConcurrentModification(t *testing.T) {
 	// This is a race condition we want to detect
 	go func() {
 		// Modify file after a brief delay
-		os.WriteFile(filePath, []byte("modified content\n"), 0644)
+		_ = os.WriteFile(filePath, []byte("modified content\n"), 0644)
 	}()
 
 	// Try to replace
@@ -285,7 +285,9 @@ func TestReplaceInDirectory_SkipsSubdirectories(t *testing.T) {
 	// Create files and subdirectory
 	createTestFile(t, tmpDir, "file1.txt", "target\n")
 	subDir := filepath.Join(tmpDir, "subdir")
-	os.Mkdir(subDir, 0755)
+	if err := os.Mkdir(subDir, 0755); err != nil {
+		t.Fatal(err)
+	}
 	createTestFile(t, subDir, "file2.txt", "target\n")
 
 	config := Config{
@@ -422,8 +424,10 @@ func TestReplaceInDirectory_PartialFailure(t *testing.T) {
 
 	badPath := filepath.Join(tmpDir, "bad.txt")
 	createTestFile(t, tmpDir, "bad.txt", "target\n")
-	os.Chmod(badPath, 0000)
-	defer os.Chmod(badPath, 0644)
+	if err := os.Chmod(badPath, 0000); err != nil {
+		t.Fatal(err)
+	}
+	defer func() { _ = os.Chmod(badPath, 0644) }()
 
 	config := Config{
 		Search:  "target",
@@ -449,7 +453,9 @@ func TestReplaceInDirectories_MixedValidInvalid(t *testing.T) {
 	defer cleanupTestDir(t, tmpDir)
 
 	validDir := filepath.Join(tmpDir, "valid")
-	os.Mkdir(validDir, 0755)
+	if err := os.Mkdir(validDir, 0755); err != nil {
+		t.Fatal(err)
+	}
 	createTestFile(t, validDir, "test.txt", "target\n")
 
 	config := Config{

main_fuzz_test.go

@@ -200,12 +200,12 @@ func TestReplaceInLine_RandomInputs(t *testing.T) {
 		t.Skip("Skipping randomized test in short mode")
 	}
 
-	rand.Seed(42) // Deterministic randomness
+	r := rand.New(rand.NewSource(42)) // Deterministic randomness
 
 	for i := 0; i < 1000; i++ {
-		line := randomString(rand.Intn(1000))
-		search := randomString(rand.Intn(50))
-		replace := randomString(rand.Intn(50))
+		line := randomString(r.Intn(1000))
+		search := randomString(r.Intn(50))
+		replace := randomString(r.Intn(50))
 
 		// Should not panic
 		func() {
@@ -235,11 +235,11 @@ func TestContainsWholeWord_RandomInputs(t *testing.T) {
 		t.Skip("Skipping randomized test in short mode")
 	}
 
-	rand.Seed(42)
+	r := rand.New(rand.NewSource(42))
 
 	for i := 0; i < 1000; i++ {
-		text := randomString(rand.Intn(500))
-		word := randomString(rand.Intn(50))
+		text := randomString(r.Intn(500))
+		word := randomString(r.Intn(50))
 
 		func() {
 			defer func() {
@@ -269,12 +269,12 @@ func TestWholeWordReplace_RandomInputs(t *testing.T) {
 		t.Skip("Skipping randomized test in short mode")
 	}
 
-	rand.Seed(42)
+	r := rand.New(rand.NewSource(42))
 
 	for i := 0; i < 500; i++ {
-		line := randomString(rand.Intn(500))
-		search := randomString(rand.Intn(30))
-		replace := randomString(rand.Intn(30))
+		line := randomString(r.Intn(500))
+		search := randomString(r.Intn(30))
+		replace := randomString(r.Intn(30))
 
 		func() {
 			defer func() {
@@ -300,11 +300,11 @@ func TestCountReplacements_RandomInputs(t *testing.T) {
 		t.Skip("Skipping randomized test in short mode")
 	}
 
-	rand.Seed(42)
+	r := rand.New(rand.NewSource(42))
 
 	for i := 0; i < 1000; i++ {
-		line := randomString(rand.Intn(500))
-		search := randomString(rand.Intn(30))
+		line := randomString(r.Intn(500))
+		search := randomString(r.Intn(30))
 
 		func() {
 			defer func() {

main_test.go

@@ -423,8 +423,12 @@ func TestReplaceInDirectories_MultiDir(t *testing.T) {
 
 	dir1 := filepath.Join(tmpDir, "dir1")
 	dir2 := filepath.Join(tmpDir, "dir2")
-	os.Mkdir(dir1, 0755)
-	os.Mkdir(dir2, 0755)
+	if err := os.Mkdir(dir1, 0755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.Mkdir(dir2, 0755); err != nil {
+		t.Fatal(err)
+	}
 
 	createTestFile(t, dir1, "test1.txt", "hello world\n")
 	createTestFile(t, dir2, "test2.txt", "hello again\n")

test_files/pkg1/handler.go

@@ -1,3 +1,5 @@
+//go:build ignore
+
 package pkg1
 
 import (

test_files/pkg1/types.go

@@ -1,3 +1,5 @@
+//go:build ignore
+
 package pkg1
 
 import (

test_files/pkg2/search.go

@@ -1,3 +1,5 @@
+//go:build ignore
+
 package pkg2
 
 import (

test_files/pkg2/utils.go

@@ -1,3 +1,5 @@
+//go:build ignore
+
 package pkg2
 
 import "strings"

trash/test_data/test2.go

@@ -1,3 +1,5 @@
+//go:build ignore
+
 package main
 
 func newFunction() {