From 4d6a30a69e2036ea72bca196a871c8cbeab37cbd Mon Sep 17 00:00:00 2001
From: Daumantas Kavolis <daumantas.kavolis@sensmetry.com>
Date: Fri, 16 Jun 2023 13:15:22 +0300
Subject: [PATCH] Need to check that left row is also non-zero so that columns
 are not subtracted twice

---
 lib/src/tree_cursor.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/src/tree_cursor.c b/lib/src/tree_cursor.c
index 0512b914..7b820983 100644
--- a/lib/src/tree_cursor.c
+++ b/lib/src/tree_cursor.c
@@ -101,7 +101,7 @@ static inline Length length_sub_zero(Length a, Length b) {
   // length_sub doesn't account for 0 row subtraction, i.e. only columns
   // should be subtracted, but changing point_sub breaks other tests
   Length result = length_sub(a, b);
-  if (b.extent.row == 0) {
+  if (b.extent.row == 0 && a.extent.row != 0) {
     result.extent.column -= b.extent.column;
   }
   return result;