What a root ctl write says is the session's in the log, msg -, not the active pane's

A session builtin written to /ctl runs at the active pane, so its messages were logged under that pane's serial, as if the pane had said them. They are now `msg -`, and still shown on the active pane.

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

3 files changed, 21 insertions, 1 deletions

diff --git a/src/Messages.zig b/src/Messages.zig
index ea62041f..cc4b3656 100644
--- a/src/Messages.zig
+++ b/src/Messages.zig
@@ -407,7 +407,7 @@ pub fn blendRgb(from: [3]u8, to: [3]u8, amount: f32) [3]u8 {
 
 fn logMessage(p: *Pardes, id: usize, text: []const u8) void {
     if (text.len == 0) return;
-    const serial: u32 = if (id < MAX_PANES) if (p.panes[id]) |pane| pane.serial else 0 else 0;
+    const serial: u32 = if (p.fs.session_write) 0 else if (id < MAX_PANES) if (p.panes[id]) |pane| pane.serial else 0 else 0;
     const kept = text[0..@min(text.len, LoggedMessage.cap)];
     // /log hears every one: a client that retried and failed the same way
     // is waiting on that second line. Only the +Messages view collapses.
diff --git a/src/fs.zig b/src/fs.zig
index 2dc3394b..42d761ca 100644
--- a/src/fs.zig
+++ b/src/fs.zig
@@ -1260,6 +1260,9 @@ pub const Namespace = struct {
     /// the first error one reports (`failure`) fails the write, as acme's
     /// ctl answers a command's error (editors/acme/xfid.c:700).
     no_prompt: bool = false,
+    /// The root ctl is running a session builtin: its messages are the
+    /// session's, logged `msg -`, though shown on the active pane.
+    session_write: bool = false,
     refused: bool = false,
     failure: [256]u8 = undefined,
     failure_len: u16 = 0,
diff --git a/src/ninep/ctl.zig b/src/ninep/ctl.zig
index 8b73e8f7..bb562672 100644
--- a/src/ninep/ctl.zig
+++ b/src/ninep/ctl.zig
@@ -344,6 +344,8 @@ pub fn writeRoot(p: *Pardes, req: Req) Reply {
                 continue;
             }
             if (p.panes[p.active] == null) return Reply.fail(req.tag, E.NOENT);
+            p.fs.session_write = true;
+            defer p.fs.session_write = false;
             if (runBuiltin(p, req, p.active, line)) |refusal| return refusal;
         }
     }
@@ -742,6 +744,21 @@ test "a second lock is refused until the holder unlocks or closes, and binds nob
     for (p.fs.opens) |o| try testing.expect(o.node == 0);
 }
 
+test "a message from a root ctl write is the session's in the log" {
+    const p = try withFile(testing.allocator, "x\n");
+    defer p.deinit();
+    p.update(.tick); // the pane's `new` is logged before the log is opened
+    while (p.nextEffect()) |_| {}
+    const log = @intFromEnum(tree.TopFile.log);
+    const f = call(p, .{ .tag = 1, .op = .open, .node = log }).reply.handle;
+    const frozen = call(p, .{ .tag = 2, .op = .read, .node = log, .handle = f, .size = 8192 }).bytes.len;
+    _ = call(p, .{ .tag = 3, .op = .write, .node = log, .handle = f, .data = "follow" });
+    try testing.expectEqual(Status.ok, wr(p, @intFromEnum(tree.TopFile.ctl), "Kill\n").reply.status);
+    // The builtin's name, then what it said: both the session's.
+    try testing.expectEqualStrings("msg - Kill\n", call(p, .{ .tag = 4, .op = .read, .node = log, .handle = f, .off = frozen, .size = 4096 }).bytes);
+    try testing.expectEqualStrings("msg - Kill: nothing running\n", call(p, .{ .tag = 5, .op = .read, .node = log, .handle = f, .off = frozen, .size = 4096 }).bytes);
+}
+
 test "a look takes acme's :addr and file:addr, and a miss changes nothing" {
     const gpa = testing.allocator;
     const p = try withFile(gpa, "foo x foo y\nbar\n");