[PATCH] leak in rl_filename_completion_function

[Grisha Levit]

If rl_filename_rewrite_hook returns a new string for a filename (which
I guess only happens on macOS with bash), it is in most cases not
free-d.

run() {
for ((i=0; i<=10000; i++)); do
    ((i%1000)) || ps -o rss= $BASHPID
    compgen -f . >/dev/null
done
}
$ (run)
  2160
  4576
  6864
  9040
 11232
 13424
 15584
 17712
 19856
 22000
 24144

---
diff --git a/lib/readline/complete.c b/lib/readline/complete.c
index bf7cc856..99556a35 100644
--- a/lib/readline/complete.c
+++ b/lib/readline/complete.c
@@ -2521,6 +2521,9 @@ rl_filename_completion_function (const char
*text, int state)
   convfn = dentry = 0;
   while (directory && (entry = readdir (directory)))
     {
+      if (convfn != dentry)
+        xfree (convfn);
+
       convfn = dentry = entry->d_name;
       convlen = dentlen = D_NAMLEN (entry);

@@ -2572,6 +2575,9 @@ rl_filename_completion_function (const char
*text, int state)
          users_dirname = (char *)NULL;
        }

+      if (convfn != dentry)
+        xfree (convfn);
+
       return (char *)NULL;
     }
   else