get multiple JSON messages working

kitty/fonts/list.py

@@ -40,10 +40,10 @@ def handle_io(from_kitten: BinaryIO, to_kitten: BinaryIO) -> None:
     def send_to_kitten(x: Any) -> None:
         to_kitten.write(json.dumps(x).encode())
         to_kitten.write(b'\n')
+        to_kitten.flush()
 
     try:
         send_to_kitten(create_family_groups(add_variable_data=True))
-        to_kitten.write(as_json().encode())
         for line in from_kitten:
             cmd = json.loads(line)
             action = cmd['action']
@@ -54,6 +54,7 @@ def handle_io(from_kitten: BinaryIO, to_kitten: BinaryIO) -> None:
 
 
 def main(argv: Sequence[str]) -> None:
+    import os
     import subprocess
     import sys
     from threading import Thread
@@ -62,7 +63,10 @@ def main(argv: Sequence[str]) -> None:
     argv = list(argv)
     if '--psnames' in argv:
         argv.remove('--psnames')
-    p = subprocess.Popen([kitten_exe(), '__list_fonts__'], stdin=subprocess.PIPE, stdout=subprocess.PIPE)
+    pass_fds = []
+    if os.environ.get('KITTY_STDIO_FORWARDED'):
+        pass_fds.append(int(os.environ['KITTY_STDIO_FORWARDED']))
+    p = subprocess.Popen([kitten_exe(), '__list_fonts__'], stdin=subprocess.PIPE, stdout=subprocess.PIPE, pass_fds=pass_fds)
     Thread(target=handle_io, args=(p.stdout, p.stdin), daemon=True).start()
     try:
         raise SystemExit(p.wait())

tools/cmd/list_fonts/main.go

@@ -12,8 +12,16 @@ import (
 
 var _ = fmt.Print
 var debugprintln = tty.DebugPrintln
+
 var json_decoder *json.Decoder
 
+func json_decode(v any) error {
+	if err := json_decoder.Decode(v); err != nil {
+		return fmt.Errorf("Failed to decode JSON from kitty with error: %w", err)
+	}
+	return nil
+}
+
 func main() (rc int, err error) {
 	json_decoder = json.NewDecoder(os.Stdin)
 	lp, err := loop.New()

tools/cmd/list_fonts/ui.go

@@ -187,7 +187,7 @@ func (h *handler) initialize() {
 	h.rl = readline.New(h.lp, readline.RlInit{DontMarkPrompts: true, Prompt: "Family: "})
 	h.draw_screen()
 	go func() {
-		h.set_worker_error(json_decoder.Decode(&h.fonts))
+		h.set_worker_error(json_decode(&h.fonts))
 		h.lp.WakeupMainThread()
 	}()
 }