asciidoc writer, checklists fix

[ricnorr]

Requesting a code review. See issue #7798

[jgm]

In general this looks very good.

Some questions: I checked the asciidoc documentation for task lists, and found this:
https://docs.asciidoctor.org/asciidoc/latest/lists/checklist/
This suggests that

1. task lists are a built-in feature of asciidoc, not an extension that would make sense to disable, and
2. they only work for bullet lists, not ordered lists.

I might be wrong in one of these impressions -- in which case correct me.
But if these things are right, then I think the code for task lists should be removed from the clause for OrderedList. And either we should make task_lists part of the default extensions for asciidoc (not just "all extensions"), or we should make this code unconditional so that it is not sensitive to an extension. (Either of these would also avoid something I thought was awkward in the test suite, using "all extensions" as if it is a default in defopts.)

[ricnorr]

In general this looks very good.

Some questions: I checked the asciidoc documentation for task lists, and found this: https://docs.asciidoctor.org/asciidoc/latest/lists/checklist/ This suggests that

1. task lists are a built-in feature of asciidoc, not an extension that would make sense to disable, and
2. they only work for bullet lists, not ordered lists.

I might be wrong in one of these impressions -- in which case correct me. But if these things are right, then I think the code for task lists should be removed from the clause for OrderedList. And either we should make task_lists part of the default extensions for asciidoc (not just "all extensions"), or we should make this code unconditional so that it is not sensitive to an extension. (Either of these would also avoid something I thought was awkward in the test suite, using "all extensions" as if it is a default in defopts.)

Yes, you are right, review fix please

[jgm]

This should be formatted like the others, so the = lines up.

[jgm]

If we leave task_lists as an extension that can be disabled, then it makes sense to test what happens when it is disabled. But I'm still not sure why we should make task list rendering something you can disable with an extension.

So, I'd favor

• removing task_list from the available extensions for asciidoc.
• changing the code to do the task list transformation if asciidoctorVariant is set in WriterState, otherwise not. (A cursory glance through the original asciidoc user guide https://asciidoc-py.github.io/userguide.html doesn't show anything about checklists, so it seems to be an asciidoctor-only feature.)

With these changes, task list syntax will be used automatically with -t asciidoctor but not with -t asciidoc, which I think is what we want. Extensions should be used only when it makes sense to disable them.

[ricnorr]

Fixed, review please

[jgm]

I'd like to avoid the API change this would require.
Why not just call handleTaskListItem, and add Ext_task_lists to the extensions parameter when calling it?

[ricnorr]

done

[jgm]

Great, thanks!