Incremental output rendering

[sudo-tee]

[cameronr]

The code is still pretty rough but I was (just this morning) able to use it while working on it, so that's a milestone :)

I'll keep cranking away on it and here are the things on my todo list:

• diff rendering isn't rendering all of the highlights when streaming
• the scrolling gets wonky (at least in my config) sometimes i think this is fixed now
• first pass on lifecycle management
• i think extmarks are off by one in tool rendering (no space after tool block and next section header)?
• wrong type for _calculate_revert_stats (state.messages is {info: Message, parts: MessagePart[]}[]|nil)
• autodiscover json files to test
• fix / commands
• update next/prev_message to work with renderer
• hook contextual actions back up
• add appropriate type annotations
• significant code cleanup: a bunch of the code is really gross, particularly how the streaming renderer works with session formatter. once the streaming code is good enough, a bunch of session formatting code can be removed. my plan is to try and just replay all of the events from the session fetch through the streaming renderer.
• message/part caches: it prolly makes sense to have a unified way to track things we have rendered so we know what thing corresponds to which lines.
• the message/part removed code has never been tested (but replacing parts has been)
• testing error handling
• look at undo / redo / snapshots
• highlighting mentions
• robustify network canceling
• don't render empty assistant message at the end (i think just from stats / tokens update)?
• more complex usage testing
• fix FIXMEs

Testing

tests/manual/README.md covers how to use the replay system.

When I see something that doesn't look right, I save the streamed events and then check them in the replay tool. Once the issue is fixed, I use :ReplaySave to save the desired output and add a unit test

I also have a keymap for reformatting the session using session_formatter:

 ['<leader>aR'] = { function() require('opencode.ui.ui').render_output(true) end },

As I fix more bugs, there should be less and less need for that.

(moving my todo list from the pr to this issue for tracking)

[sudo-tee]

Incremental rendering has been merged