Add support for the secondary device attributes control code (DA2)

kitty/screen.py

@@ -832,10 +832,20 @@ class Screen(QObject):
 
         .. versionadded:: 0.5.0
         """
-        # We only implement "primary" DA which is the only DA request
-        # VT102 understood, see ``VT102ID`` in ``linux/drivers/tty/vt.c``.
-        if mode == 0:
-            self.write_process_input(ctrl.CSI + b"?6c")
+        # Use the same responses as libvte v0.46 running in termite
+        # Ignore mode since vte seems to ignore it
+        if kwargs.get('secondary') == '>':
+            # http://www.vt100.net/docs/vt510-rm/DA2.html
+            # If you implement xterm keycode querying you can change this to
+            # mimic xterm instead (>41;327;0c) then vim wont need terminfo to
+            # get keycodes (see :help xterm-codes)
+            self.write_process_input(ctrl.CSI + b'>1;4600;0c')
+        else:
+            # xterm gives: [[?64;1;2;6;9;15;18;21;22c
+            # use the simpler vte response, since we dont support
+            # windowing/horizontal scrolling etc.
+            # [[?64;1;2;6;9;15;18;21;22c
+            self.write_process_input(ctrl.CSI + b"?62c")
 
     def report_device_status(self, mode):
         """Reports terminal status or cursor position.

pyte/streams.py

@@ -297,7 +297,7 @@ class Stream(object):
                 #        arguments.
                 params = []
                 current = bytearray()
-                private = False
+                private = secondary = False
                 while True:
                     char = yield
                     if char == b"?":
@@ -305,8 +305,7 @@ class Stream(object):
                     elif char in ALLOWED_IN_CSI:
                         basic_dispatch[char]()
                     elif char in SP_OR_GT:
-                        # We don't handle secondary DA atm.
-                        pass
+                        secondary = char.decode('ascii')  # Added by Kovid
                     elif char in CAN_OR_SUB:
                         # If CAN or SUB is received during a sequence, the
                         # current sequence is aborted; terminal displays
@@ -325,7 +324,10 @@ class Stream(object):
                             if private:
                                 csi_dispatch[char](*params, private=True)
                             else:
-                                csi_dispatch[char](*params)
+                                if secondary:  # Added by Kovid
+                                    csi_dispatch[char](*params, secondary=secondary)
+                                else:
+                                    csi_dispatch[char](*params)
                             break  # CSI is finished.
             elif char == OSC:
                 code = yield