A command line runs as its own command pane unless it is clicked at a shell's prompt

A middle click, an exec write or a tag word that no builtin knows was typed
into some terminal for the pane's directory, sharing whatever state that
shell was in and answering nothing, so a misspelling vanished into a shell.
Now only a line clicked at an interactive terminal's prompt is typed there.
From anywhere else it runs as a command pane: a terminal whose child is
$SHELL -c the line in the pane's directory, full emulation, which shows its
output and then exit N from the host's reaping of the child, and stays. A
finished command pane is the next command's for its directory, which runs
below what it showed after a '% line' line (acme appends to +Errors and never
clears it, util.c:213); a running one gets a second pane. Kill ends a command
pane's whole process group, the log records run and exit, exec reads back the
command pane's serial, and a line is at most 1 KB, read off the pane as the
host forks rather than carried in every spawn effect. ttyForDir's search for
a free shell is gone. The goldens of chordcut, cmdword and layout-open change
where a file's exec now opens a command pane, and ttytaken is rewritten to
exec from the terminal itself; docs/open-questions.md records the decision.

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

1 files changed, 7 insertions, 1 deletions

diff --git a/src/ninep/ctl.zig b/src/ninep/ctl.zig
index c1cfa1f6..deb64565 100644
--- a/src/ninep/ctl.zig
+++ b/src/ninep/ctl.zig
@@ -67,7 +67,12 @@ fn run(p: *Pardes, id: usize, exec: bool, text: []const u8) void {
         return noteResult(p, context);
     }
     const before = Serials.snapshot(p);
-    if (exec) _ = pardes.exec.execute(p, id, text) else look.lookAt(p, id, text);
+    // An exec answers the pane it went to: a command pane it reused, or
+    // the terminal it typed into.
+    const went: ?usize = if (exec) pardes.exec.execute(p, id, text) else blk: {
+        look.lookAt(p, id, text);
+        break :blk null;
+    };
     const after = Serials.snapshot(p);
     var created = false;
     for (after.list[0..after.len]) |serial| if (std.mem.indexOfScalar(u32, before.list[0..before.len], serial) == null) {
@@ -75,6 +80,7 @@ fn run(p: *Pardes, id: usize, exec: bool, text: []const u8) void {
         created = true;
     };
     if (created) return;
+    if (went) |dst| if (p.panes[dst]) |pane| return noteResult(p, pane.serial);
     noteResult(p, if (exec) context else (p.panes[p.active] orelse return).serial);
 }