fix: Remove line length limit on MacOS for input prompts (#839)

This caused inputs to be truncated on MacOS terminals.

cli/cliui/cliui_darwin.go

@@ -0,0 +1,31 @@
+//go:build darwin
+// +build darwin
+
+package cliui
+
+import (
+	"golang.org/x/sys/unix"
+
+	"golang.org/x/xerrors"
+)
+
+func removeLineLengthLimit(inputFD int) (func(), error) {
+	termios, err := unix.IoctlGetTermios(inputFD, unix.TIOCGETA)
+	if err != nil {
+		return nil, xerrors.Errorf("get termios: %w", err)
+	}
+	newState := *termios
+	// MacOS has a default line limit of 1024. See:
+	// https://unix.stackexchange.com/questions/204815/terminal-does-not-accept-pasted-or-typed-lines-of-more-than-1024-characters
+	//
+	// This removes canonical input processing, so deletes will not function
+	// as expected. This _seems_ fine for most use-cases, but is unfortunate.
+	newState.Lflag &^= unix.ICANON
+	err = unix.IoctlSetTermios(inputFD, unix.TIOCSETA, &newState)
+	if err != nil {
+		return nil, xerrors.Errorf("set termios: %w", err)
+	}
+	return func() {
+		_ = unix.IoctlSetTermios(inputFD, unix.TIOCSETA, termios)
+	}, nil
+}

cli/cliui/cliui_other.go

@@ -0,0 +1,10 @@
+//go:build !darwin
+// +build !darwin
+
+package cliui
+
+import "golang.org/x/xerrors"
+
+func removeLineLengthLimit(_ int) (func(), error) {
+	return nil, xerrors.New("not implemented")
+}

cli/cliui/prompt.go

@@ -8,6 +8,7 @@ import (
 	"io"
 	"os"
 	"os/signal"
+	"runtime"
 	"strings"
 
 	"github.com/bgentry/speakeasy"
@@ -42,10 +43,21 @@ func Prompt(cmd *cobra.Command, opts PromptOptions) (string, error) {
 	go func() {
 		var line string
 		var err error
+
 		inFile, valid := cmd.InOrStdin().(*os.File)
 		if opts.Secret && valid && isatty.IsTerminal(inFile.Fd()) {
 			line, err = speakeasy.Ask("")
 		} else {
+			if runtime.GOOS == "darwin" && valid {
+				var restore func()
+				restore, err = removeLineLengthLimit(int(inFile.Fd()))
+				if err != nil {
+					errCh <- err
+					return
+				}
+				defer restore()
+			}
+
 			reader := bufio.NewReader(cmd.InOrStdin())
 			line, err = reader.ReadString('\n')