From bf57d0c60691963e597408827b74646d368658ec Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= <daniel@ekloef.se>
Date: Tue, 9 Jun 2020 17:32:34 +0200
Subject: [PATCH] csi: \E[3J: reset render.last_cursor.row if necessary

This fixes a crash that occurred when the last rendered cursor cell
had scrolled off screen, and \E[3J (clear scrollback) was executed.
---
 CHANGELOG.md | 2 ++
 csi.c        | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7ac1f035..d11caa1b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -55,6 +55,8 @@
 * Glyphs overflowing into surrounding cells
   (https://codeberg.org/dnkl/foot/issues/21).
 * Sixel images being erased when printing text next to them.
+* Crash when last rendered cursor cell had scrolled off screen and
+  `\E[J3` was executed.
 
 
 ### Security
diff --git a/csi.c b/csi.c
index 56346e6e..37400953 100644
--- a/csi.c
+++ b/csi.c
@@ -506,6 +506,9 @@ csi_dispatch(struct terminal *term, uint8_t final)
                             continue;
                     }
 
+                    if (term->render.last_cursor.row == term->grid->rows[i])
+                        term->render.last_cursor.row = NULL;
+
                     grid_row_free(term->grid->rows[i]);
                     term->grid->rows[i] = NULL;
                 }