diff --git a/internal/machine/caddyconfig/controller.go b/internal/machine/caddyconfig/controller.go
index 5f5a65bd..f1051741 100644
--- a/internal/machine/caddyconfig/controller.go
+++ b/internal/machine/caddyconfig/controller.go
@@ -242,8 +242,8 @@ func (c *Controller) writeCaddyfileIfChanged(caddyfile string) error {
 // caddyfileBody returns the Caddyfile content without its first line, which carries a generation timestamp that
 // rotates on every regeneration.
 func caddyfileBody(caddyfile string) string {
-	if i := strings.IndexByte(caddyfile, '\n'); i >= 0 {
-		return caddyfile[i+1:]
+	if _, after, ok := strings.Cut(caddyfile, "\n"); ok {
+		return after
 	}
 	return caddyfile
 }
diff --git a/internal/machine/caddyconfig/controller_test.go b/internal/machine/caddyconfig/controller_test.go
index a394a82f..86135258 100644
--- a/internal/machine/caddyconfig/controller_test.go
+++ b/internal/machine/caddyconfig/controller_test.go
@@ -30,8 +30,7 @@ func TestContainerFingerprint_EqualCoversAllFields(t *testing.T) {
 	assert.True(t, base.Equal(base), "base fingerprint must be equal to itself")
 
 	rt := reflect.TypeOf(base)
-	for i := 0; i < rt.NumField(); i++ {
-		field := rt.Field(i)
+	for field := range rt.Fields() {
 		t.Run(field.Name, func(t *testing.T) {
 			t.Parallel()
 
diff --git a/internal/machine/caddyconfig/mocks_test.go b/internal/machine/caddyconfig/mocks_test.go
index ca0f73f4..38401b3c 100644
--- a/internal/machine/caddyconfig/mocks_test.go
+++ b/internal/machine/caddyconfig/mocks_test.go
@@ -62,7 +62,7 @@ type MockCaddyfileValidator_Validate_Call struct {
 // Validate is a helper method to define mock.On call
 //   - ctx context.Context
 //   - caddyfile string
-func (_e *MockCaddyfileValidator_Expecter) Validate(ctx interface{}, caddyfile interface{}) *MockCaddyfileValidator_Validate_Call {
+func (_e *MockCaddyfileValidator_Expecter) Validate(ctx any, caddyfile any) *MockCaddyfileValidator_Validate_Call {
 	return &MockCaddyfileValidator_Validate_Call{Call: _e.mock.On("Validate", ctx, caddyfile)}
 }
 
diff --git a/internal/machine/docker/server.go b/internal/machine/docker/server.go
index 2a4ff65e..813f15c1 100644
--- a/internal/machine/docker/server.go
+++ b/internal/machine/docker/server.go
@@ -683,9 +683,7 @@ func (s *Server) CreateServiceContainer(
 		// Apply the pre-deploy hook overrides.
 		config.Cmd = spec.PreDeploy.Command
 
-		for k, v := range spec.PreDeploy.Env {
-			envVars[k] = v
-		}
+		maps.Copy(envVars, spec.PreDeploy.Env)
 		envVars["UNCLOUD_HOOK_PRE_DEPLOY"] = "true"
 		config.Env = envVars.ToSlice()
 
diff --git a/pkg/client/logmerger_test.go b/pkg/client/logmerger_test.go
index 570c9e73..daf5835d 100644
--- a/pkg/client/logmerger_test.go
+++ b/pkg/client/logmerger_test.go
@@ -227,7 +227,7 @@ func TestLogMerger_ZeroTimestampForwarding(t *testing.T) {
 	merger := NewLogMerger([]<-chan api.ServiceLogEntry{ch}, LogMergerOptions{})
 	output := merger.Stream()
 
-	for i := 0; i < zeroCount; i++ {
+	for range zeroCount {
 		ch <- testEntry(api.LogStreamStdout, time.Time{}, "zero")
 	}
 	t1 := time.Now()
@@ -237,7 +237,7 @@ func TestLogMerger_ZeroTimestampForwarding(t *testing.T) {
 	results := collectEntries(t, output, 0)
 	require.Len(t, results, zeroCount+1)
 
-	for i := 0; i < zeroCount; i++ {
+	for i := range zeroCount {
 		assert.True(t, results[i].Timestamp.IsZero(), "entry %d should have zero timestamp", i)
 		assert.Equal(t, "zero", string(results[i].Message))
 	}