A program that asked for focus reports (1004) hears CSI I when its pane takes the keyboard and CSI O when it gives it up, to another pane, a tag or another window

The core has a window-focus event now, from SDL's window focus and from
the tty's own focus reports (vaxis turns 1004 on outside); the detached
wire carries it: version 10. The test shell's ESC]777;mouse;focus;<1|0>
fakes the window's.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 7 insertions, 4 deletions

diff --git a/src/detached/wire.zig b/src/detached/wire.zig
index 9a1ab608..c9d9b578 100644
--- a/src/detached/wire.zig
+++ b/src/detached/wire.zig
@@ -12,7 +12,7 @@ const ShaderAnimation = pardes.config.Runtime.ShaderAnimation;
 /// to be refused, which is what this number is for.
 /// 8: one layer type: a tag band carries all its rows (not a layer per
 /// line), and a frame carries the core's placed regions after its layers.
-pub const version: u16 = 9;
+pub const version: u16 = 10;
 
 /// The Chrome palette is carried field by field as its declaration lists
 /// them, so any change to it changes the wire: bump `version`, then this.
@@ -58,6 +58,7 @@ pub const ClientTag = enum(u8) {
     pinch = 0x1b,
     touch_scroll = 0x1c,
     pointer_leave = 0x1d,
+    focus = 0x1e,
 };
 
 // Session control precedes display-local effects.
@@ -1076,6 +1077,7 @@ pub fn encodeClient(out: []u8, msg: ClientMsg) Error![]const u8 {
             .pinch => |v| try w.putF32(v),
             .touch_scroll => |v| try w.putF32(v),
             .pointer_leave => {},
+            .focus => |focused| try w.putBool(focused),
             // See `clientTag`: no tag, so nothing to encode.
             .output, .eof, .exited, .lsp_resp, .pipe_resp, .file_changed, .tick => unreachable,
         },
@@ -1138,6 +1140,7 @@ pub fn decodeClient(tag: u8, payload: []const u8) Error!ClientMsg {
         .pinch => .{ .event = .{ .pinch = try r.getF32() } },
         .touch_scroll => .{ .event = .{ .touch_scroll = try r.getF32() } },
         .pointer_leave => .{ .event = .pointer_leave },
+        .focus => .{ .event = .{ .focus = try r.getBool() } },
     };
     try r.end();
     return msg;
@@ -1222,7 +1225,7 @@ pub fn clientBound(msg: ClientMsg) usize {
     return msg_slack + switch (msg) {
         .hello, .bye => 0,
         .event => |ev| switch (ev) {
-            .mouse, .resize, .pdf_scroll, .pinch, .touch_scroll, .pointer_leave => 0,
+            .mouse, .resize, .pdf_scroll, .pinch, .touch_scroll, .pointer_leave, .focus => 0,
             .key => |k| k.text.len,
             .paste => |b| b.len,
             .command => |line| line.len,
@@ -1455,7 +1458,7 @@ test "detached wire: a session is never told to do a frontend's remembering" {
     // Adding a name here is meant to be an ARGUMENT, not a formality, and the
     // bar is one sentence: A HUMAN DID IT. A keystroke, a click, a pinch, a
     // window resized, a paste, a command line executed, a pointer leaving the
-    // window — plus the two session words that say who is speaking. A pty's
+    // window, the window's focus — plus the two session words that say who is speaking. A pty's
     // output, a worker's answer, a watched file's new bytes and an animation
     // tick all fail that bar the same way: nobody did them, a machine reported
     // them, and the machine that reports them is the one already holding the
@@ -1468,7 +1471,7 @@ test "detached wire: a session is never told to do a frontend's remembering" {
         "resize",        "paste",
         "command",       "pdf_scroll",
         "pinch",         "touch_scroll",
-        "pointer_leave",
+        "pointer_leave", "focus",
     };
 
     // One: the tag set is exactly that, named rather than counted, so