diagnostics: support sending ALE output to Neovim's diagnostics API

[mathstuf]

Closes #4005

This resurrects #4135. I'll roll with it locally to test it out more (especially to see if that off-by-one is actually fixed or not). Other than test suite bits, the review comments from there have been addressed.

Pulling the TODO item from the original PR description:

• Fix off by 1 issue reported by @daliusd below
• Maybe good idea to add a test test_linting_sets_signs.vader or test_sign_placement.vader that tests ALE signs are disabled when neovim diagnostics are enabled.
• Also maybe add a test to test_cursor_warnings.vader that tests cursor messages is not echoed when neovim diagnostics are enabled.
• Figure out if it's OK to disable loclist/quickfix like we do currently
• Fix issue with g:ale_virtualtext_cursor reported below

No tests yet (beyond updating the existing config one for the new option).

[w0rp]

If you can address the remaining TODO items here, I'll merge this one. I'm not working on it myself because I'm not a regular NeoVim user. (I'm waiting until NeoVim is named 1.0 and has some promises to not change default configuration for some time.)

[mathstuf]

I've been running with it for a while now and it works AFAICT. However, I still need to investigate these items to see if they're a problem yet. Not sure when I'll get time for that though.

I'm waiting until NeoVim is named 1.0 and has some promises to not change default configuration for some time.

FWIW, I've only needed to set two things (that I should have been setting anyways) when migrating. That's other than the massive s/vim/nvim/g changes that needed to be done.

[bluz71]

If you can address the remaining TODO items here, I'll merge this one. I'm not working on it myself because I'm not a regular NeoVim user. (I'm waiting until NeoVim is named 1.0 and has some promises to not change default configuration for some time.)

Neovim 1.0 could be years away.
Current stable release is 0.8.
Current development release is 0.9.
Since 0.5 release, Neovim is releasing a stable version (0.6, 0.7, 0.8) on a six month cadence (give or take).

0.5 --> 0.6 had major LSP API changes, basically a new module vim.diagnostic was extracted out of vim.lsp.

With respect to ALE, I am very confident that the APIs provided by Neovim that ALE would need to use to satisfy the PR are stable now and are very unlikely to change.

Best regards.

[w0rp]

If you can address the remaining TODO items here, I'll merge this one. I'm not working on it myself because I'm not a regular NeoVim user. (I'm waiting until NeoVim is named 1.0 and has some promises to not change default configuration for some time.)

Neovim 1.0 could be years away. Current stable release is 0.8. Current development release is 0.9. Since 0.5 release, Neovim is releasing a stable version (0.6, 0.7, 0.8) on a six month cadence (give or take).

0.5 --> 0.6 had major LSP API changes, basically a new module vim.diagnostic was extracted out of vim.lsp.

With respect to ALE, I am very confident that the APIs provided by Neovim that ALE would need to use to satisfy the PR are stable now and are very unlikely to change.

Best regards.

That's good. I was speaking about my personal editor of choice. I'll be using Vim until Neovim hits 1.0.

[w0rp]

I and @Angelchev are fixing this now.

[w0rp]

@hsanson I'm going to disable ALE signs when sending messages to Neovim diagnostics is enabled, as there are ways of getting signs to appear for Neovim diagnostics. We can look into that later.