A word at /tagexec or a column's exec that makes, acts on and focuses no pane reads back nothing

Newcol written to /tagexec read back `1`, the pane with the keyboard, which
the word never touched. That was a pane word's fallback (a pane's exec
answers the pane it ran at) applied to a tag no pane owns. A word in a
column's or the workspace's tag now answers the pane it made, refilled, went
to or focused, and otherwise nothing.

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

2 files changed, 19 insertions, 0 deletions

diff --git a/src/ninep/cols.zig b/src/ninep/cols.zig
index c049e0f3..b1ca954c 100644
--- a/src/ninep/cols.zig
+++ b/src/ninep/cols.zig
@@ -227,6 +227,19 @@ test "New written to a column's exec makes its scratch in the session's director
     try testing.expectEqualStrings("/project/src/+New", p.panes[p.active].?.file.?.path);
 }
 
+test "a tagexec word that makes, acts on and focuses no pane reads back nothing" {
+    const p = try th.withFile(testing.allocator, "x\n");
+    defer p.deinit();
+    const tagexec = @intFromEnum(tree.TopFile.tagexec);
+    try testing.expectEqual(tree.Status.ok, th.wr(p, tagexec, "Newcol\n").reply.status);
+    try testing.expectEqualStrings("", th.rd(p, tagexec, 0, 64).bytes);
+    // A column's New makes one, and answers it.
+    const col_exec = tree.Node.ofCol(layout.columnSerial(p, 0), .exec);
+    try testing.expectEqual(tree.Status.ok, th.wr(p, col_exec, "New\n").reply.status);
+    var want: [16]u8 = undefined;
+    try testing.expectEqualStrings(try std.fmt.bufPrint(&want, "{d}\n", .{p.panes[p.active].?.serial}), th.rd(p, col_exec, 0, 64).bytes);
+}
+
 test "New written to a column's ctl reads back the new pane alone, as its exec does" {
     const p = try th.withFile(testing.allocator, "x\n");
     defer p.deinit();
diff --git a/src/ninep/ctl.zig b/src/ninep/ctl.zig
index d6230308..d86d6047 100644
--- a/src/ninep/ctl.zig
+++ b/src/ninep/ctl.zig
@@ -93,6 +93,12 @@ pub fn run(p: *Pardes, id: usize, exec: bool, text: []const u8, in_tag: bool) vo
     // touched.
     if (p.fs.refilled) |serial| if (p.paneBySerial(serial) != null) return noteResult(p, serial);
     if (went) |dst| if (p.panes[dst]) |pane| return noteResult(p, pane.serial);
+    // A word in a column's or the workspace's tag ran at no pane: it
+    // answers one only if it focused one (Newcol answers nothing).
+    if (p.exec_header) {
+        if (p.active != id) if (p.panes[p.active]) |pane| noteResult(p, pane.serial);
+        return;
+    }
     noteResult(p, if (exec) context else (p.panes[p.active] orelse return).serial);
 }