a suggestion of implementation of stop_word.c

Hi, I found a fragile code in implementation of stop_word.c that may occur null pointer dereference, and I have shown the execution sequence of the program that may generate the bug on the figure below. The red text illustrates the steps that generate the bug, the file path can be seen in the blue framed section.

if a guard is here to provide this case, just like line 97-line 99 in above figure, i think it good for robustness of project
Although the code shown is for version 10.3 but is still exist in current version

would you can help to check if this?thank you for your effort and patience!