Hi,

love-0.10 and 11 ship with Polyline.cpp which has a loop that can
access array at -1 offset as it doesn't check for vertex_count. I found
this in 2 games (Arco, Moonring) and there may be more. Upstream
accepted my PR [1], so best to fix our port, too!

ok?

[1] https://github.com/love2d/love/pull/2097
Index: 0.10/Makefile
===================================================================
RCS file: /cvs/ports/games/love/0.10/Makefile,v
diff -u -p -r1.4 Makefile
--- 0.10/Makefile	28 Aug 2024 15:34:10 -0000	1.4
+++ 0.10/Makefile	22 Oct 2024 03:42:44 -0000
@@ -1,6 +1,6 @@
 VERSION =		0.10.2
 USE_LUAJIT =		No
-REVISION =		2
+REVISION =		3
 
 SHARED_LIBS=		love-${VERSION}	0.0
 
Index: 0.10/patches/patch-src_modules_graphics_opengl_Polyline_cpp
===================================================================
RCS file: 0.10/patches/patch-src_modules_graphics_opengl_Polyline_cpp
diff -N 0.10/patches/patch-src_modules_graphics_opengl_Polyline_cpp
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ 0.10/patches/patch-src_modules_graphics_opengl_Polyline_cpp	22 Oct 2024 03:42:44 -0000
@@ -0,0 +1,14 @@
+backport of https://github.com/love2d/love/pull/2097
+
+Index: src/modules/graphics/opengl/Polyline.cpp
+--- src/modules/graphics/opengl/Polyline.cpp.orig
++++ src/modules/graphics/opengl/Polyline.cpp
+@@ -104,7 +104,7 @@ void Polyline::render(const float *coords, size_t coun
+ 	}
+ 
+ 	// Add the degenerate triangle strip.
+-	if (extra_vertices)
++	if (extra_vertices && vertex_count > 0)
+ 	{
+ 		vertices[vertex_count + 0] = vertices[vertex_count - 1];
+ 		vertices[vertex_count + 1] = vertices[overdraw_vertex_start];
Index: 11/Makefile
===================================================================
RCS file: /cvs/ports/games/love/11/Makefile,v
diff -u -p -r1.7 Makefile
--- 11/Makefile	28 Aug 2024 15:34:10 -0000	1.7
+++ 11/Makefile	22 Oct 2024 03:42:44 -0000
@@ -3,7 +3,7 @@
 NOT_FOR_ARCHS =		${BE_ARCHS}
 
 VERSION =		11.5
-REVISION =		1
+REVISION =		2
 
 SHARED_LIBS =		love-${VERSION}	0.0
 
Index: 11/patches/patch-src_modules_graphics_Polyline_cpp
===================================================================
RCS file: 11/patches/patch-src_modules_graphics_Polyline_cpp
diff -N 11/patches/patch-src_modules_graphics_Polyline_cpp
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ 11/patches/patch-src_modules_graphics_Polyline_cpp	22 Oct 2024 03:42:44 -0000
@@ -0,0 +1,14 @@
+backport of https://github.com/love2d/love/pull/2097
+
+Index: src/modules/graphics/Polyline.cpp
+--- src/modules/graphics/Polyline.cpp.orig
++++ src/modules/graphics/Polyline.cpp
+@@ -100,7 +100,7 @@ void Polyline::render(const Vector2 *coords, size_t co
+ 	}
+ 
+ 	// Add the degenerate triangle strip.
+-	if (extra_vertices)
++	if (extra_vertices && vertex_count > 0)
+ 	{
+ 		vertices[vertex_count + 0] = vertices[vertex_count - 1];
+ 		vertices[vertex_count + 1] = vertices[overdraw_vertex_start];

• love-polyline-fix.diff (3K)