A Newcol refused because the panes' tags would not fit logs its err alone and spends no column serial

Newcol tries its column before keeping it: the new column is inserted,
the panes' rows are shared out again, and where a pane would be left
under its tag and two rows the column is taken back. The trial showed.
insertColumn logged `newcol N` and the take-back `delcol N`, so a
follower saw a column come and go around the err. Laying the column out
also gave it a serial, so the next column made skipped one. The trial is
now unannounced, since insert and drop have unlogged forms. A refusal puts
the serial counter back where it was, after first giving every existing
column its serial so the trial's is the only one spent. Only a column
that stays is logged, and it gets the next serial.

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

1 files changed, 10 insertions, 2 deletions

diff --git a/src/pardes.zig b/src/pardes.zig
index f0d22d57..f61ba797 100644
--- a/src/pardes.zig
+++ b/src/pardes.zig
@@ -4971,8 +4971,13 @@ pub const Pardes = struct {
         // An empty window (Delcol took the last column): its first column.
         if (layout.firstColumn(p)) |c| return tagline.enterHeader(p, c);
         const col = p.keyboardColumn(from_id) orelse return;
+        // A trial: laying it out gives it a serial (layout.compute), which a
+        // refusal takes back. Every other column has its own already, so
+        // the counter as it is now is the trial's to return to.
+        for (0..p.ncol) |k| _ = layout.columnSerial(p, k);
+        const unspent = p.next_column_serial;
         // Said, not silently nothing: "no space" is 9ns's word for ENOSPC.
-        const c = layout.insertColumn(p, col, false) orelse {
+        const c = layout.insertColumnUnannounced(p, col, false) orelse {
             var said: [96]u8 = undefined;
             return p.reportFailure(from_id, if (p.ncol >= MAX_COLS)
                 std.fmt.bufPrint(&said, "Newcol: no space for a column: {d} max", .{MAX_COLS}) catch "Newcol: no space for a column"
@@ -4984,10 +4989,13 @@ pub const Pardes = struct {
         // out again, and where they cannot hold every minimum there is no
         // new column, as a size too small is refused.
         for (0..p.ncol) |k| if (!layout.columnAtMinimums(p, k) and !layout.shareColumn(p, k)) {
-            layout.dropColumn(p, c);
+            layout.dropColumnUnannounced(p, c);
+            p.next_column_serial = unspent;
             layout.compute(p);
             return p.reportFailure(from_id, "Newcol: no space for a column: the panes' tags would not fit");
         };
+        // Kept: now it has a serial, and the log hears of it.
+        layout.noteColumn(p, "newcol", layout.columnSerial(p, c));
         tagline.enterHeader(p, c);
     }