Fix lint errors

- Remove Go 1.22+ unnecessary loop variable copy (copyloopvar)
- Replace unused parameters with _ (revive)
- Add nolint directive for FinishEarly naming (staticcheck ST1012)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: znull

pipe/memorylimit_test.go

@@ -150,7 +150,7 @@ func testMemoryLimit(t *testing.T, mbs int, limit uint64, stage pipe.Stage) (str
 	p.Add(
 		pipe.Function(
 			"write-to-less",
-			func(ctx context.Context, _ pipe.Env, _ io.Reader, stdout io.Writer) error {
+			func(_ context.Context, _ pipe.Env, _ io.Reader, stdout io.Writer) error {
 				// Write some nonsense data to less.
 				var bytes [1_000_000]byte
 				for i := 0; i < mbs; i++ {
@@ -185,7 +185,7 @@ func testMemoryLimitWithObserver(t *testing.T, mbs int, limit uint64, stage pipe
 	p.Add(
 		pipe.Function(
 			"write-to-less",
-			func(ctx context.Context, _ pipe.Env, _ io.Reader, stdout io.Writer) error {
+			func(_ context.Context, _ pipe.Env, _ io.Reader, stdout io.Writer) error {
 				var bytes [1_000_000]byte
 				for i := 0; i < mbs; i++ {
 					_, err := stdout.Write(bytes[:])

pipe/pipe_matching_test.go

@@ -360,8 +360,6 @@ func TestPipeTypes(t *testing.T) {
 			},
 		},
 	} {
-		tc := tc
-
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
 

pipe/pipeline.go

@@ -29,6 +29,7 @@ type Env struct {
 // and is not reported to the caller.
 //
 //revive:disable:error-naming
+//nolint:staticcheck // ST1012: FinishEarly is the intentional name for this sentinel error
 var FinishEarly = errors.New("finish stage early")
 
 //revive:enable:error-naming
@@ -68,7 +69,7 @@ type Pipeline struct {
 	panicHandler StagePanicHandler
 }
 
-var emptyEventHandler = func(e *Event) {}
+var emptyEventHandler = func(_ *Event) {}
 
 type NewPipeFn func(opts ...Option) *Pipeline
 

pipe/pipeline_test.go

@@ -1007,7 +1007,7 @@ func BenchmarkMoreDataUnbuffered(b *testing.B) {
 		p.Add(
 			pipe.Function(
 				"seq",
-				func(ctx context.Context, _ pipe.Env, stdin io.Reader, stdout io.Writer) error {
+				func(_ context.Context, _ pipe.Env, _ io.Reader, stdout io.Writer) error {
 					for i := 1; i <= 100000; i++ {
 						fmt.Fprintln(stdout, i)
 					}
@@ -1025,7 +1025,7 @@ func BenchmarkMoreDataUnbuffered(b *testing.B) {
 			pipe.Command("cat"),
 			pipe.LinewiseFunction(
 				"count",
-				func(ctx context.Context, _ pipe.Env, line []byte, stdout *bufio.Writer) error {
+				func(_ context.Context, _ pipe.Env, _ []byte, _ *bufio.Writer) error {
 					count++
 					return nil
 				},
@@ -1052,7 +1052,7 @@ func BenchmarkMoreDataBuffered(b *testing.B) {
 		p.Add(
 			pipe.Function(
 				"seq",
-				func(ctx context.Context, _ pipe.Env, stdin io.Reader, stdout io.Writer) error {
+				func(_ context.Context, _ pipe.Env, _ io.Reader, stdout io.Writer) error {
 					out := bufio.NewWriter(stdout)
 					for i := 1; i <= 1000000; i++ {
 						fmt.Fprintln(out, i)
@@ -1071,7 +1071,7 @@ func BenchmarkMoreDataBuffered(b *testing.B) {
 			pipe.Command("cat"),
 			pipe.LinewiseFunction(
 				"count",
-				func(ctx context.Context, _ pipe.Env, line []byte, stdout *bufio.Writer) error {
+				func(_ context.Context, _ pipe.Env, _ []byte, stdout *bufio.Writer) error {
 					count++
 					return nil
 				},