sdl: main + tests additions

2 files changed, 37 insertions, 0 deletions

diff --git a/main.zig b/main.zig
index 3db83d94..732a4710 100644
--- a/main.zig
+++ b/main.zig
@@ -481,9 +481,24 @@ fn forkTerm(gpa: std.mem.Allocator, init_cols: u16, init_rows: u16, cwd: ?[*:0]c
         .rows = init_rows,
     };
     t.stream = t.term.vtStream();
+    // Answer terminal QUERIES back into the pty. Apps (nushell/reedline, helix, fzf
+    // — anything on crossterm) send a DSR cursor-position report (ESC[6n) at startup
+    // and BLOCK waiting for the reply. ghostty computes the reply but drops it unless
+    // this effect is wired, so the app spins forever ("nushell never opens"). Only
+    // real terminals need it (file/image stubs read no pty). See ptyReport.
+    t.stream.handler.effects.write_pty = ptyReport;
     return t;
 }
 
+// ghostty calls this with a reply (cursor-position report, operating status, ...)
+// to send back to the child. The handler's `terminal` is our Term.term field, so
+// recover the owning Term and echo the bytes into its pty as if the child typed
+// them. termWrite no-ops on a closed pty, so a late report after EOF is harmless.
+fn ptyReport(handler: *ghostty_vt.TerminalStream.Handler, data: [:0]const u8) void {
+    const t: *Term = @fieldParentPtr("term", handler.terminal);
+    termWrite(t, data);
+}
+
 // peel a trailing :NNN (or :NNN:) line suffix: main.zig:100 -> {main.zig, 100}.
 fn parsePathLine(tok: []const u8) struct { path: []const u8, line: usize } {
     var sep: usize = 0;
diff --git a/tests.zig b/tests.zig
index 83e42dad..0a81feb6 100644
--- a/tests.zig
+++ b/tests.zig
@@ -589,4 +589,26 @@ pub fn main(init: std.process.Init) !void {
             return error.ColumnCollapseReflow;
         }
     }
+
+    // 18. DEVICE-QUERY REPLIES: full-screen apps (nushell/reedline, helix, fzf — all
+    //     crossterm) send a DSR cursor-position report (ESC[6n) at startup and BLOCK
+    //     until the terminal answers. pardes must reply into the pty; without the
+    //     write_pty effect the reply is dropped and the app spins forever ("nushell
+    //     never opens"). Mode-independent. Run a command that (in raw mode, like a
+    //     real app) emits ESC[6n and only echoes its marker AFTER it reads the reply
+    //     — the marker appears only if pardes answered the query.
+    {
+        var hs8 = try Harness.init(gpa, exe.ptr, 24, 80);
+        defer hs8.deinit();
+        try hs8.expectWaitFor("build.zig", 8000, "fresh terminal never auto-ls'd");
+        try hs8.send("\x02"); // normal -> tty
+        try hs8.pump(600);
+        // -icanon so the reply's bytes reach `read` without a newline; read until the
+        // reply terminator 'R' (ESC[<row>;<col>R) with a timeout, and print the marker
+        // ONLY if the read SUCCEEDS (a reply arrived). The marker is split with ''
+        // so it appears solely in the command's OUTPUT, never in the echoed command
+        // line — otherwise the on-screen command text would false-match it.
+        try hs8.send("stty -icanon -echo min 1 time 0; printf '\\033[6n'; read -r -d R -t 3 _c && printf 'ZZCPR''OK\\n'; stty sane\r");
+        try hs8.expectWaitFor("ZZCPROK", 8000, "app blocked on its ESC[6n query — pardes dropped the reply (device queries not answered)");
+    }
 }