From 2a4071f8dcad478b7e8150a31bdff999d112c171 Mon Sep 17 00:00:00 2001
From: Glen Whitney <gwhitney@post.harvard.edu>
Date: Sat, 27 Jul 2019 23:54:16 -0400
Subject: [PATCH] Prevent some near-startup coredumps.

   Fixes #38.
---
 src/common/main.c  | 2 +-
 src/common/sheet.c | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/common/main.c b/src/common/main.c
index b9db34e..0c96e00 100644
--- a/src/common/main.c
+++ b/src/common/main.c
@@ -330,7 +330,7 @@ static void do_attribute(Sheet *cursheet, Key action)
   adj = LEFT;
   do_mark(cursheet, GET_MARK_CUR);
   onecell = SAME_LOC(cursheet->mark1, cursheet->mark2);
-  fcell = CELL_AT(cursheet, cursheet->mark1);
+  fcell = safe_cell_at(cursheet, cursheet->mark1);
   if (action != ADJUST_LOCK && onecell && locked(fcell))
   {
     line_msg(_("Cell attribute:"),_("Cell is locked"));
diff --git a/src/common/sheet.c b/src/common/sheet.c
index cbe3d14..f3f5dd8 100644
--- a/src/common/sheet.c
+++ b/src/common/sheet.c
@@ -446,6 +446,7 @@ void forceupdate(Sheet *sheet)
   Cell *cell;
 
   assert(sheet!=(Sheet*)0);
+  if (sheet->sheet == (Cell **)0) return;
   for (ALL_CELLS_IN_SHEET(sheet,i,cell))
     if (cell != NULLCELL)
       cell->updated = cell->clock_t0 = cell->clock_t1 = cell->clock_t2 = 0;