1 files changed, 26 insertions, 0 deletions
diff --git a/src/ninep/tree.zig b/src/ninep/tree.zig
index aec3cab7..414a0b6e 100644
--- a/src/ninep/tree.zig
+++ b/src/ninep/tree.zig
@@ -713,8 +713,11 @@ fn open(p: *Pardes, req: Req, target: Target) Reply {
             // closing it leaves the pane alone.
             .new => {
                 const slot = p.freeSlot() orelse return failText(req.tag, E.NOSPC, std.fmt.bufPrint(&p.fs.ename, "pane/new: " ++ pardes.Messages.no_pane_slots, .{pardes.MAX_PANES}) catch "no space for a pane");
+                p.fs.no_pane_slot = false;
                 p.newScratchFor(p.active, .fs);
                 const made = p.panes[slot] orelse return Reply.fail(req.tag, E.NFILE);
+                // No room in its column: it closes at the step's end.
+                if (p.unplaced.isSet(slot)) return failText(req.tag, E.NOSPC, p.fs.ename[0..p.fs.no_pane_slot_len]);
                 return .{ .tag = req.tag, .handle = made.serial };
             },
             .screen => .{ .snapshot = null },
@@ -1427,6 +1430,8 @@ test "editor paths resolve to the same nodes the wire serves" {
 test "at the pane cap, pane/new, look and New each say so, and look reads back empty" {
     const p = try th.withFile(testing.allocator, "x\n");
     defer p.deinit();
+    // Tall enough that the column holds every pane at its tag and two rows.
+    p.update(.{ .resize = .{ .cols = 80, .rows = pardes.MAX_PANES * 4 } });
     const new = @intFromEnum(TopFile.new);
     while (p.freeSlot() != null) try testing.expectEqual(Status.ok, call(p, .{ .tag = 1, .op = .open, .node = new }).reply.status);
     var want: [64]u8 = undefined;
@@ -1496,3 +1501,24 @@ test "look and exec read back what their own open's write touched; a fresh open
     try testing.expectEqualStrings(try std.fmt.bufPrint(&want, "{d}\n", .{said}), call(p, .{ .tag = 9, .op = .read, .node = exec, .handle = fresh, .size = 64 }).bytes);
     for ([_]u32{ mine, theirs, fresh }) |hh| _ = call(p, .{ .tag = 10, .op = .release, .node = exec, .handle = hh, .opened = true });
 }
+
+test "no placement leaves a pane shorter than its tag and two rows; a full column refuses the next" {
+    const p = try th.withFile(testing.allocator, "x\n");
+    defer p.deinit();
+    const new = @intFromEnum(TopFile.new);
+    var made: usize = 1;
+    const refused = while (made < pardes.MAX_PANES) : (made += 1) {
+        const a = call(p, .{ .tag = 1, .op = .open, .node = new });
+        if (a.reply.status == .err) break a;
+    } else return error.NeverRefused;
+    try testing.expectEqual(E.NOSPC, refused.errno());
+    try testing.expect(std.mem.indexOf(u8, refused.reply.ename, "no space for a pane in that column") != null);
+    p.sync();
+    var count: usize = 0;
+    for (p.panes) |slot| count += @intFromBool(slot != null);
+    try testing.expectEqual(made, count); // the refused one is gone
+    for (0..p.ncol) |c| for (p.col_panes[c][0..p.col_n[c]]) |k| {
+        if (p.col_n[c] > 1 and !p.panes[k].?.collapsed)
+            try testing.expect(p.rects[k].h >= p.panes[k].?.tag_rows + pardes.layout.min_body_rows);
+    };
+}