Intermittent NullPointerException: link-destination

[damianw]

• Markwon version: 4.1.1

We are occasionally seeing reports of the following error during rendering. It's very intermittent, and is probably some kind of race condition (we are rendering multiple documents in parallel using the same Markwon instance as previously mentioned in this other issue). I don't think I can really provide more information as I haven't yet been able to reproduce it manually.

Caused by java.lang.NullPointerException: link-destination
       at io.noties.markwon.Prop.require(Prop.java:52)
       at io.noties.markwon.core.factory.LinkSpanFactory.getSpans(LinkSpanFactory.java:18)
       at io.noties.markwon.MarkwonVisitorImpl.setSpansForNodeOptional(MarkwonVisitorImpl.java:261)
       at io.noties.markwon.MarkwonVisitorImpl.setSpansForNodeOptional(MarkwonVisitorImpl.java:254)
       at io.noties.markwon.core.CorePlugin$15.visit(CorePlugin.java:514)
       at io.noties.markwon.core.CorePlugin$15.visit(CorePlugin.java:502)
       at io.noties.markwon.MarkwonVisitorImpl.visit(MarkwonVisitorImpl.java:172)
       at io.noties.markwon.MarkwonVisitorImpl.visit(MarkwonVisitorImpl.java:125)
       at org.commonmark.node.Link.accept(Link.java:38)
       at io.noties.markwon.MarkwonVisitorImpl.visitChildren(MarkwonVisitorImpl.java:203)
       at io.noties.markwon.core.CorePlugin$14.visit(CorePlugin.java:474)
       at io.noties.markwon.core.CorePlugin$14.visit(CorePlugin.java:463)
       at io.noties.markwon.MarkwonVisitorImpl.visit(MarkwonVisitorImpl.java:172)
       at io.noties.markwon.MarkwonVisitorImpl.visit(MarkwonVisitorImpl.java:140)
       at org.commonmark.node.Paragraph.accept(Paragraph.java:7)
       at io.noties.markwon.MarkwonVisitorImpl.visitChildren(MarkwonVisitorImpl.java:203)
       at io.noties.markwon.MarkwonVisitorImpl.visit(MarkwonVisitorImpl.java:174)
       at io.noties.markwon.MarkwonVisitorImpl.visit(MarkwonVisitorImpl.java:75)
       at org.commonmark.node.Document.accept(Document.java:7)
       at io.noties.markwon.MarkwonImpl.render(MarkwonImpl.java:66)

[noties]

Hello @damianw !

Thank you for the hint. RenderProps were still re-used between multiple render calls. I've fixed that and published 4.1.2-SNAPSHOT version

[noties]

Hello @damianw !

As you can imagine this kind of issue is hard to track. I could not reproduce it with code, but there is a big chance that this behavior was caused by RenderProps being shared between multiple visitors. This was an oversight and I think this should be fixed in 4.1.2 release that I had just published 🙌

[damianw]

Thanks @noties! I will update and see if it fixes the issue. 👍