Support starting PTY with a size

code-asher · code-asher · commit a8360d1dae77 · 2023-07-20T18:27:11.000-08:00
You get unexpected padding in screen if you try to resize afterward.
diff --git a/pty/pty.go b/pty/pty.go
@@ -80,13 +80,19 @@ type WithFlags interface {
 	EchoEnabled() (bool, error)
 }
 
-// Options represents a an option for a PTY.
+// Options represents an option for a PTY.
 type Option func(*ptyOptions)
 
+type Winsize struct {
+	Height uint16
+	Width  uint16
+}
+
 type ptyOptions struct {
 	logger    *log.Logger
 	sshReq    *ssh.Pty
 	setGPGTTY bool
+	size      *Winsize
 }
 
 // WithSSHRequest applies the ssh.Pty request to the PTY.
@@ -113,6 +119,13 @@ func WithGPGTTY() Option {
 	}
 }
 
+// WithSize sets the initial size at which to spawn the PTY.
+func WithSize(size *Winsize) Option {
+	return func(opts *ptyOptions) {
+		opts.size = size
+	}
+}
+
 // New constructs a new Pty.
 func New(opts ...Option) (PTY, error) {
 	return newPty(opts...)
diff --git a/pty/pty_other.go b/pty/pty_other.go
@@ -26,6 +26,12 @@ func newPty(opt ...Option) (retPTY *otherPty, err error) {
 	if err != nil {
 		return nil, err
 	}
+	if opts.size != nil {
+		_ = pty.Setsize(ptyFile, &pty.Winsize{
+			Rows: opts.size.Height,
+			Cols: opts.size.Width,
+		})
+	}
 	opty := &otherPty{
 		pty:  ptyFile,
 		tty:  ttyFile,
