commit e0cbaa50fa7e97a8b7404041a59caac47b3949a5
author Roberto Ierusalimschy <roberto@inf.puc-rio.br> Tue Dec 17 10:49:55 2019 -0300
committer Roberto Ierusalimschy <roberto@inf.puc-rio.br> Tue Dec 17 10:49:55 2019 -0300
tree aca8070ca14b0823b2bec895610f43d0013feffe
parent 37474873203f247552021ab5856ab69d777166a2

Added test for NULL in string.format("%p")

ISO C states that standard library functions should not be called
with NULL arguments, unless stated otherwise. 'sprintf' does not
state otherwise, and it doesn't hurt to be on the safe side.

lstrlib.c

diff --git a/lstrlib.c b/lstrlib.c
index 586e0d7..e47a1d8 100644
--- a/lstrlib.c
+++ b/lstrlib.c
@@ -1271,6 +1271,8 @@
         }
         case 'p': {
           const void *p = lua_topointer(L, arg);
+          if (p == NULL)
+            p = "(null)";  /* NULL not a valid parameter in ISO C 'printf' */
           nb = l_sprintf(buff, maxitem, form, p);
           break;
         }