From f67fec978a9296c651ec06bd2f43686d34ff86ee Mon Sep 17 00:00:00 2001
From: Gabriel Schneider <gbrls@0x4200.cafe>
Date: Fri, 14 Aug 2026 13:40:29 -0300
Subject: look: richer path/range parsing, pdf rendering, corner-drag and
 stepgrain snapshots

---
 src/tty/tty.zig | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

(limited to 'src/tty/tty.zig')

diff --git a/src/tty/tty.zig b/src/tty/tty.zig
index eadc3a9d..f6d095e5 100644
--- a/src/tty/tty.zig
+++ b/src/tty/tty.zig
@@ -456,6 +456,11 @@ pub fn run(init: std.process.Init, opts: pardes.Options) !void {
     // per-slot spawn generation: a reused pane id ignores the old shell's
     // late pty_eof (which would otherwise close the NEW pty on that slot)
     var gens: [pardes.MAX_PANES]u32 = @splat(0);
+    // ...and the core's one way to ask about those ptys: is a pane's tty still
+    // the prompt we forked? Installed here rather than polled per frame (see
+    // the cwd loop) and re-installed on a replay core, which owns a fresh set
+    // of panes over this same table.
+    core.tty_query = .{ .ctx = &ptys, .taken = &ttyTakenAt };
     // the single in-flight language query (see the .lsp effect)
     var lsp_task: ?std.Io.Future(anyerror!void) = null;
     // Selection filters may overlap: a second submit supersedes the first in
@@ -811,6 +816,7 @@ pub fn run(init: std.process.Init, opts: pardes.Options) !void {
             while (image_iterator.next()) |handle| vx.freeImage(tty.writer(), handle.id);
             kitty_handles.clearRetainingCapacity();
             nc.native_images = vx.caps.kitty_graphics;
+            nc.tty_query = .{ .ctx = &ptys, .taken = &ttyTakenAt };
             core.deinit();
             core = nc;
             if (comptime pardes.pdf_enabled) {
@@ -822,7 +828,10 @@ pub fn run(init: std.process.Init, opts: pardes.Options) !void {
             }
         }
 
-        // live cwd for tags/look: cheap per-pane lookup, per frame
+        // live cwd for tags/look: cheap per-pane lookup, per frame. Whether the
+        // pane's tty still belongs to the prompt we forked is NOT polled here —
+        // it is a walk through /proc and nothing draws it, so the core pulls it
+        // through ttyQuery below, at the Exec that cares.
         for (&ptys, 0..) |*slot, id| if (slot.*) |pt| {
             var lbuf: [1024]u8 = undefined;
             if (look.shellCwd(pt.pid, &lbuf)) |cwd| core.setCwd(id, cwd);
@@ -989,7 +998,9 @@ fn drainEffects(
             }
             const child = forkShell(core.shellBin(), cwd_z, core.screen_h, core.screen_w);
             ptys[sp.pane] = .{ .file = child.file, .pid = child.pid, .reader = .{ .any_future = null, .result = {} } };
-            // report the pane's starting directory back to the core (tags)
+            // report the pane's starting directory back to the core (tags). The
+            // slot needs no occupancy reset: nothing is remembered, and the next
+            // Exec asks about the shell that is there now.
             var lbuf: [1024]u8 = undefined;
             if (look.shellCwd(child.pid, &lbuf)) |wd| core.setCwd(sp.pane, wd);
             if (threads_ok) {
@@ -1275,6 +1286,17 @@ fn winchWatch(loop: *Loop, vx: *vaxis.Vaxis, tty: *vaxis.Tty) void {
     }
 }
 
+/// The core's `tty_query`: answer for one pane out of this host's pty table.
+/// Lazy by construction — it runs only where the core is about to type a
+/// command line, so the /proc walk costs nothing on an ordinary frame. A pane
+/// with no pty of ours (a document, a slot whose shell already died) is not a
+/// terminal a program can be holding.
+fn ttyTakenAt(ctx: ?*anyopaque, pane: usize) bool {
+    const table: *const [pardes.MAX_PANES]?Pty = @ptrCast(@alignCast(ctx orelse return false));
+    const pt = table[pane] orelse return false;
+    return look.ttyTaken(pt.pid, pt.file.handle);
+}
+
 fn forkShell(bin: []const u8, cwd: ?[*:0]const u8, rows: u16, cols: u16) struct { file: std.Io.File, pid: posix.pid_t } {
     var master: c_int = undefined;
     // resolved BEFORE the fork, into this frame, which the child inherits:
-- 
cgit v1.3