feat(lsp): initial support for dynamic capabilities (#23681)

- `client.dynamic_capabilities` is an object that tracks client register/unregister
- `client.supports_method` will additionally check if a dynamic capability supports the method, taking document filters into account. But only if the client enabled `dynamicRegistration` for the capability
- updated the default client capabilities to include dynamicRegistration for:
    - formatting
    - rangeFormatting
    - hover
    - codeAction
    - hover
    - rename

runtime/lua/vim/lsp/_dynamic.lua

@@ -0,0 +1,109 @@
+local wf = require('vim.lsp._watchfiles')
+
+--- @class lsp.DynamicCapabilities
+--- @field capabilities table<string, lsp.Registration[]>
+--- @field client_id number
+local M = {}
+
+--- @param client_id number
+function M.new(client_id)
+  return setmetatable({
+    capabilities = {},
+    client_id = client_id,
+  }, { __index = M })
+end
+
+function M:supports_registration(method)
+  local client = vim.lsp.get_client_by_id(self.client_id)
+  if not client then
+    return false
+  end
+  local capability = vim.tbl_get(client.config.capabilities, unpack(vim.split(method, '/')))
+  return type(capability) == 'table' and capability.dynamicRegistration
+end
+
+--- @param registrations lsp.Registration[]
+--- @private
+function M:register(registrations)
+  -- remove duplicates
+  self:unregister(registrations)
+  for _, reg in ipairs(registrations) do
+    local method = reg.method
+    if not self.capabilities[method] then
+      self.capabilities[method] = {}
+    end
+    table.insert(self.capabilities[method], reg)
+  end
+end
+
+--- @param unregisterations lsp.Unregistration[]
+--- @private
+function M:unregister(unregisterations)
+  for _, unreg in ipairs(unregisterations) do
+    local method = unreg.method
+    if not self.capabilities[method] then
+      return
+    end
+    local id = unreg.id
+    for i, reg in ipairs(self.capabilities[method]) do
+      if reg.id == id then
+        table.remove(self.capabilities[method], i)
+        break
+      end
+    end
+  end
+end
+
+--- @param method string
+--- @param opts? {bufnr?: number}
+--- @return lsp.Registration? (table|nil) the registration if found
+--- @private
+function M:get(method, opts)
+  opts = opts or {}
+  opts.bufnr = opts.bufnr or vim.api.nvim_get_current_buf()
+  for _, reg in ipairs(self.capabilities[method] or {}) do
+    if not reg.registerOptions then
+      return reg
+    end
+    local documentSelector = reg.registerOptions.documentSelector
+    if not documentSelector then
+      return reg
+    end
+    if M.match(opts.bufnr, documentSelector) then
+      return reg
+    end
+  end
+end
+
+--- @param method string
+--- @param opts? {bufnr?: number}
+--- @private
+function M:supports(method, opts)
+  return self:get(method, opts) ~= nil
+end
+
+--- @param bufnr number
+--- @param documentSelector lsp.DocumentSelector
+--- @private
+function M.match(bufnr, documentSelector)
+  local ft = vim.bo[bufnr].filetype
+  local uri = vim.uri_from_bufnr(bufnr)
+  local fname = vim.uri_to_fname(uri)
+  for _, filter in ipairs(documentSelector) do
+    local matches = true
+    if filter.language and ft ~= filter.language then
+      matches = false
+    end
+    if matches and filter.scheme and not vim.startswith(uri, filter.scheme .. ':') then
+      matches = false
+    end
+    if matches and filter.pattern and not wf._match(filter.pattern, fname) then
+      matches = false
+    end
+    if matches then
+      return true
+    end
+  end
+end
+
+return M

runtime/lua/vim/lsp/buf.lua

@@ -683,11 +683,7 @@ local function on_code_action_results(results, ctx, options)
     --
     local client = vim.lsp.get_client_by_id(action_tuple[1])
     local action = action_tuple[2]
-    if
-      not action.edit
-      and client
-      and vim.tbl_get(client.server_capabilities, 'codeActionProvider', 'resolveProvider')
-    then
+    if not action.edit and client and client.supports_method('codeAction/resolve') then
       client.request('codeAction/resolve', action, function(err, resolved_action)
         if err then
           vim.notify(err.code .. ': ' .. err.message, vim.log.levels.ERROR)

runtime/lua/vim/lsp/handlers.lua

@@ -118,22 +118,30 @@ end
 
 --see: https://microsoft.github.io/language-server-protocol/specifications/specification-current/#client_registerCapability
 M['client/registerCapability'] = function(_, result, ctx)
-  local log_unsupported = false
+  local client_id = ctx.client_id
+  ---@type lsp.Client
+  local client = vim.lsp.get_client_by_id(client_id)
+
+  client.dynamic_capabilities:register(result.registrations)
+  for bufnr, _ in ipairs(client.attached_buffers) do
+    vim.lsp._set_defaults(client, bufnr)
+  end
+
+  ---@type string[]
+  local unsupported = {}
   for _, reg in ipairs(result.registrations) do
     if reg.method == 'workspace/didChangeWatchedFiles' then
       require('vim.lsp._watchfiles').register(reg, ctx)
-    else
-      log_unsupported = true
+    elseif not client.dynamic_capabilities:supports_registration(reg.method) then
+      unsupported[#unsupported + 1] = reg.method
     end
   end
-  if log_unsupported then
-    local client_id = ctx.client_id
+  if #unsupported > 0 then
     local warning_tpl = 'The language server %s triggers a registerCapability '
-      .. 'handler despite dynamicRegistration set to false. '
+      .. 'handler for %s despite dynamicRegistration set to false. '
       .. 'Report upstream, this warning is harmless'
-    local client = vim.lsp.get_client_by_id(client_id)
     local client_name = client and client.name or string.format('id=%d', client_id)
-    local warning = string.format(warning_tpl, client_name)
+    local warning = string.format(warning_tpl, client_name, table.concat(unsupported, ', '))
     log.warn(warning)
   end
   return vim.NIL
@@ -141,6 +149,10 @@ end
 
 --see: https://microsoft.github.io/language-server-protocol/specifications/specification-current/#client_unregisterCapability
 M['client/unregisterCapability'] = function(_, result, ctx)
+  local client_id = ctx.client_id
+  local client = vim.lsp.get_client_by_id(client_id)
+  client.dynamic_capabilities:unregister(result.unregisterations)
+
   for _, unreg in ipairs(result.unregisterations) do
     if unreg.method == 'workspace/didChangeWatchedFiles' then
       require('vim.lsp._watchfiles').unregister(unreg, ctx)

runtime/lua/vim/lsp/protocol.lua

@@ -697,7 +697,7 @@ function protocol.make_client_capabilities()
         didSave = true,
       },
       codeAction = {
-        dynamicRegistration = false,
+        dynamicRegistration = true,
 
         codeActionLiteralSupport = {
           codeActionKind = {
@@ -714,6 +714,12 @@ function protocol.make_client_capabilities()
           properties = { 'edit' },
         },
       },
+      formatting = {
+        dynamicRegistration = true,
+      },
+      rangeFormatting = {
+        dynamicRegistration = true,
+      },
       completion = {
         dynamicRegistration = false,
         completionItem = {
@@ -747,6 +753,7 @@ function protocol.make_client_capabilities()
       },
       definition = {
         linkSupport = true,
+        dynamicRegistration = true,
       },
       implementation = {
         linkSupport = true,
@@ -755,7 +762,7 @@ function protocol.make_client_capabilities()
         linkSupport = true,
       },
       hover = {
-        dynamicRegistration = false,
+        dynamicRegistration = true,
         contentFormat = { protocol.MarkupKind.Markdown, protocol.MarkupKind.PlainText },
       },
       signatureHelp = {
@@ -790,7 +797,7 @@ function protocol.make_client_capabilities()
         hierarchicalDocumentSymbolSupport = true,
       },
       rename = {
-        dynamicRegistration = false,
+        dynamicRegistration = true,
         prepareSupport = true,
       },
       publishDiagnostics = {

runtime/lua/vim/lsp/types.lua

@@ -35,3 +35,31 @@
 ---@field source string
 ---@field tags? lsp.DiagnosticTag[]
 ---@field relatedInformation DiagnosticRelatedInformation[]
+
+--- @class lsp.DocumentFilter
+--- @field language? string
+--- @field scheme? string
+--- @field pattern? string
+
+--- @alias lsp.DocumentSelector lsp.DocumentFilter[]
+
+--- @alias lsp.RegisterOptions any | lsp.StaticRegistrationOptions | lsp.TextDocumentRegistrationOptions
+
+--- @class lsp.Registration
+--- @field id string
+--- @field method string
+--- @field registerOptions? lsp.RegisterOptions
+
+--- @alias lsp.RegistrationParams {registrations: lsp.Registration[]}
+
+--- @class lsp.StaticRegistrationOptions
+--- @field id? string
+
+--- @class lsp.TextDocumentRegistrationOptions
+--- @field documentSelector? lsp.DocumentSelector
+
+--- @class lsp.Unregistration
+--- @field id string
+--- @field method string
+
+--- @alias lsp.UnregistrationParams {unregisterations: lsp.Unregistration[]}