Asciidoctor has no control over this behavior. Asciidoctor delegates syntax highlighting to the source highlighter. How it handles that task is up to it. Rouge apparently requires that the JSON document be complete or else it flags it as an error. So it's best to highlight a valid JSON snippet or disable syntax highlighting (by removing the source style or using a generic language like text).

The user manual mentions linenums, for example, but I've found in Rouge the syntax is numbered, not linenums.

In truth, the name doesn't matter at all. If there is an attribute in the third position, line numbering is enabled. It could be named number-all-the-lines.

[source,json,number-all-the-lines]

But the preferred syntax is the option:

[source%linenums,json]

I'd like to split the json into parts on multiple (pdf) pages.

This sounds like an Asciidoctor PDF issue. Are you putting text between the snippets, or just breaking up a single block so that it fits on different pages? If the latter, you shouldn't need to as that's what Asciidoctor PDF already does.

Thanks again for your help, Dan!

I use asciidoctor-pdf to make slides, and there are some json examples where I want part of the json on one slide and the rest on the next slide for conceptual reasons. There is text in between (for example, the slide title). I'm pretty sure there's no way to force a page break in the middle of a code block since a code block is meant to stay together as much as possible.

It would be fine if the lexer ignored syntax errors. I brought up this issue on the Rouge page (linked earlier in the github conversation) and they are starting to agree that the lexer shouldn't necessarily highlight errors. They mentioned using a CSS rule to ignore error highlighting, but as these are PDFs, I don't think there is a way for me to control this from the asciidoctor-pdf side of things.

I could go in and make modifications to the lexer to ignore syntax errors, but that's going to be hard to maintain with my current build setup for such a small detail. For now, I will just live with it. Let me know if I'm wrong and there is something to be done.