Empty URL markdown link causes java.lang.NullPointerException

[marklacroix]

Gitbucket version	4.8
Gitbucket Gist plugin version	4.4
OS	Windows, Linux

When a link with an empty URL is specified in markdown (e.g. [empty link]()), the snippet summary page (/gist) and user snippet summary page (/gist/user) fails to render with a java.lang.NullPointerException stack trace. Viewing the snippet directly does not encounter this issue.

It appears to be an issue with gitbucket core (the fixUrl method), but I am unable to replicate it in the core features of gitbucket.

Please let me know if I should open this as an issue on the main gitbucket project.

[takezoe]

Sorry for very delayed reaction. This is a bug of Markdown rendering in the side of GitBucket core. It's going to be fixed in gitbucket/gitbucket#2189.