[LyX/master] Fix lyx2lyx issue reported on ML

[Scott Kostyshak]

commit 77fc67d3f01576070bb51cedc4d578c0457f5bce
Author: Scott Kostyshak <skostysh at lyx.org>
Date:   Wed Sep 6 13:05:07 2023 -0400

    Fix lyx2lyx issue reported on ML
    
    The issue was reported on lyx-users by Chris Menzel [1].
    
    Patch is from José Matos [2].
    
    [1] https://www.mail-archive.com/search?l=mid&q=BD744D7E-54B4-4E95-A4E3-6B28F4987DE1%40gmail.com
    [2] https://www.mail-archive.com/search?l=mid&q=c2ac54c2322d24051f171558ad8487ea4f7078ed.camel%40gmail.com
---
 lib/lyx2lyx/parser_tools.py |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/lib/lyx2lyx/parser_tools.py b/lib/lyx2lyx/parser_tools.py
index cc22236..96abb1c 100644
--- a/lib/lyx2lyx/parser_tools.py
+++ b/lib/lyx2lyx/parser_tools.py
@@ -689,7 +689,8 @@ def count_pars_in_inset(lines, i):
   pars = 0
   for j in range(ins[1], ins[2]):
       m = re.match(r'\\begin_layout (.*)', lines[j])
-      if m and get_containing_inset(lines, j)[1] == ins[1]:
+      found_inset = get_containing_inset(lines, j)
+      if m and found_inset and found_inset[1] == ins[1]:
           pars += 1
 
   return pars