fix: provide a fix for *nix and windows executors

internal/lefthook/run/exec/execute_unix.go

@@ -28,18 +28,11 @@ type executeArgs struct {
 	interactive, useStdin bool
 }
 
-type nullReader struct{}
-
-func (nullReader) Read(b []byte) (int, error) {
-	if len(b) == 0 {
-		return 0, nil
-	}
-
-	return 0, io.EOF
-}
-
 func (e CommandExecutor) Execute(ctx context.Context, opts Options, out io.Writer) error {
 	var in io.Reader = nullReader{}
+	if opts.UseStdin {
+		in = os.Stdin
+	}
 	if opts.Interactive && !isatty.IsTerminal(os.Stdin.Fd()) {
 		tty, err := os.Open("/dev/tty")
 		if err == nil {

internal/lefthook/run/exec/execute_windows.go

@@ -29,8 +29,13 @@ func (e CommandExecutor) Execute(ctx context.Context, opts Options, out io.Write
 		)
 	}
 
+	var in io.Reader = nullReader{}
+	if opts.Interactive || opts.UseStdin {
+		in = os.Stdin
+	}
+
 	args := &executeArgs{
-		in:   os.Stdin,
+		in:   in,
 		out:  out,
 		envs: envs,
 		root: root,

internal/lefthook/run/exec/nullReader.go

@@ -0,0 +1,10 @@
+package exec
+
+import "io"
+
+// nullReader always returns EOF.
+type nullReader struct{}
+
+func (nullReader) Read(b []byte) (int, error) {
+	return 0, io.EOF
+}