fix(lsp): workaround for inlay hint rendering + fix serverStatus handler

CHANGELOG.md

@@ -6,6 +6,17 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Fixed
+
+- LSP: If inlay hints are enabled for a buffer, force Neovim
+  to redraw them when rust-analyzer has fully initialized.
+  This is a workaround for [neovim/26511](https://github.com/neovim/neovim/issues/26511).
+- LSP: On client stop, reset the `experimental/serverStatus` handler's
+  internal state for the respective client, so that the handler can be
+  rerun on restart.
+
 ## [3.15.0] - 2024-01-11
 
 ### Added

lua/rustaceanvim/lsp.lua

@@ -4,6 +4,7 @@ local config = require('rustaceanvim.config.internal')
 local compat = require('rustaceanvim.compat')
 local types = require('rustaceanvim.types.internal')
 local rust_analyzer = require('rustaceanvim.rust_analyzer')
+local server_status = require('rustaceanvim.server_status')
 local joinpath = compat.joinpath
 
 local function override_apply_text_edits()
@@ -172,7 +173,7 @@ M.start = function(bufnr)
   lsp_start_opts.capabilities = vim.tbl_deep_extend('force', capabilities, lsp_start_opts.capabilities or {})
 
   local custom_handlers = {}
-  custom_handlers['experimental/serverStatus'] = require('rustaceanvim.server_status').handler
+  custom_handlers['experimental/serverStatus'] = server_status.handler
 
   if config.tools.hover_actions.replace_builtin_hover then
     custom_handlers['textDocument/hover'] = require('rustaceanvim.hover_actions').handler
@@ -221,6 +222,12 @@ M.stop = function(bufnr)
   bufnr = bufnr or vim.api.nvim_get_current_buf()
   local clients = rust_analyzer.get_active_rustaceanvim_clients(bufnr)
   vim.lsp.stop_client(clients)
+  if type(clients) == 'table' then
+    ---@cast clients lsp.Client[]
+    for _, client in ipairs(clients) do
+      server_status.reset_client_state(client.id)
+    end
+  end
   return clients
 end
 

lua/rustaceanvim/server_status.lua

@@ -2,16 +2,38 @@ local config = require('rustaceanvim.config.internal')
 
 local M = {}
 
-local _ran_once = false
+---@type { [integer]: boolean }
+local _ran_once = {}
 
 ---@param result RustAnalyzerInitializedStatusInternal
-function M.handler(_, result)
-  if result.quiescent and not _ran_once then
-    if config.tools.on_initialized then
-      config.tools.on_initialized(result)
+function M.handler(_, result, ctx, _)
+  -- quiescent means the full set of results is ready.
+  if not result.quiescent or _ran_once[ctx.client_id] then
+    return
+  end
+  -- rust-analyzer may provide incomplete/empty inlay hints by the time Neovim
+  -- calls the `on_attach` callback.
+  -- [https://github.com/neovim/neovim/issues/26511]
+  -- This workaround forces Neovim to redraw inlay hints if they are enabled,
+  -- as soon as rust-analyzer has fully initialized.
+  if type(vim.lsp.inlay_hint) == 'table' then
+    for _, bufnr in ipairs(vim.lsp.get_buffers_by_client_id(ctx.client_id)) do
+      if vim.lsp.inlay_hint.is_enabled(bufnr) then
+        vim.lsp.inlay_hint.enable(bufnr, false)
+        vim.lsp.inlay_hint.enable(bufnr, true)
+      end
     end
-    _ran_once = true
   end
+  -- Load user on_initialized
+  if config.tools.on_initialized then
+    config.tools.on_initialized(result)
+  end
+  _ran_once[ctx.client_id] = true
+end
+
+---@param client_id integer
+function M.reset_client_state(client_id)
+  _ran_once[client_id] = false
 end
 
 return M