Failure to open a file: Crash

[AmityWilder]

Attempting to open a file which, for any reason, fails to be opened (access denied, file not found, incompatible format, etc) causes an "unknown internal error" and crashes the application.

[AmityWilder]

I think it's possible that this error may arise from getScannerForFile returning null on error, followed by callers not performing null-checks before calling Scanner methods on that possible-null.