I am using jsoup 1.18.3 and noticed a ugly behaviour in comparison to jsoup 1.18.0.

I call jsoup like this:
Document doc = Jsoup.parse(stream, null, "");

It happens that the stream is null. This is detected by another part of my program and jsoup previously accepted the null stream. In org.jsoup.helper.DataUtil.parseInputStream(ControllableInputStream, String, String, Parser) it simply returned new Document(baseUri).

With one of the recent changes you wrap a ControllableInputStream.wrap around the stream object. Therefore the check

if (input == null) // empty body // todo reconsider?
  return new Document(baseUri);

at the top of org.jsoup.helper.DataUtil.parseInputStream(ControllableInputStream, String, String, Parser) will never return a new Document when the stream is null. Instead it crashes when detecting the charset using detectCharset from the null stream. This seems to be wrong.

Since null as a stream is supported (see @nullable in the declaration of parseInputStream, I would add this @nullable to org.jsoup.helper.DataUtil.load(InputStream, String, String) too.

Solution (not tested):
I would return null in ControllableInputStream.wrap if the stream is null.