Problem:
Diagnostic tracking used a separate bufstates table and manual
LspDetach/LspNotify autocmd management via _enable()/_refresh(),
duplicating the lifecycle logic already provided by the Capability
framework. This caused inconsistencies in how client attach/detach and
buffer teardown were handled compared to other LSP features.
Solution:
Replace the ad-hoc bufstate tracking and _enable/_refresh pattern in
vim.lsp.diagnostic with a proper Diagnostics subclass of Capability.
This cleans up a few random places in the main lsp module and client
module that were poking the diagnostics. It also fixes some pre-existing
bugs and inconsistencies that were discovered:
- Refresh diagnostics immediately on attach instead of lazily by the
first didOpen/didChange notification
- Fix Capability.active lookup in M.enable() to key by it_bufnr instead
of the filter bufnr
- Set lsp defaults before calling the _text_document_did_open_handler in
Client:on_attach() so defaults are there before any lsp notification
occurs
- Log (and return early) on any error from a diagnostic request result
instead of only returning early for server cancelled errors
Today there is a constraint that these arguments to the enable filter be
mutually exclusive, but I do not know why such a constraint exists (it
is perfectly reasonable to want to enable a capabilility for just one
buffer and just one client).
Problem:
Our LSP type system didnt have a concept of RegistrationMethods, this is where the method to dynamically register for a capability is sent to a different method endpoint then is used to call it. Eg `textDocument/semanticTokens` rather than the specific full/range/delta methods
Solution:
Extended generator to create `vim.lsp.protocol.Methods.Registration` with these registration methods. Also extend `_request_name_to_client_capability` to cover these methods. Adjust typing to suit
Problem:
Closes#31453
Solution:
Introduce `vim.lsp.Capability`, which may serve as the base class for
all LSP features that require caching data. it
- was created if there is at least one client that supports the specific method;
- was destroyed if all clients that support the method were detached.
- Apply the refactor for `folding_range.lua` and `semantic_tokens.lua`.
- Show active features in :checkhealth.
Future:
I found that these features that are expected to be refactored by
`vim.lsp.Capability` have one characteristic in common: they all send
LSP requests once the document is modified. The following code is
different, but they are all for this purpose.
- semantic tokens:
fb8dba413f/runtime/lua/vim/lsp/semantic_tokens.lua (L192-L198)
- inlay hints, folding ranges, document color
fb8dba413f/runtime/lua/vim/lsp/inlay_hint.lua (L250-L266)
I think I can sum up this characteristic as the need to keep certain
data synchronized with the latest version computed by the server.
I believe we can handle this at the `vim.lsp.Capability` level, and
I think it will be very useful.
Therefore, my next step is to implement LSP request sending and data
synchronization on `vim.lsp.Capability`, rather than limiting it to the
current create/destroy data approach.
