[breaking change] make it work for nvim 0.5.1

In nvim 0.5.1, the lsp handler signature has changed, see https://github.com/neovim/neovim/pull/15504
and LunarVim/LunarVim#1484.

README.md

@@ -22,7 +22,7 @@ add it to your own Nvim config.
 See [doc here](docs/README.md) on how to install Nvim's dependencies, Nvim
 itself, and how to set up on different platforms (Linux, macOS and Windows).
 
-**This config is tested against Nvim 0.5.0 release. No backward compatibility
+**This config is tested against Nvim 0.5.1 release. No backward compatibility
 is guaranteed.**
 
 # Features #

lua/config/lsp.lua

@@ -166,10 +166,14 @@ vim.lsp.handlers["textDocument/publishDiagnostics"] = vim.lsp.with(vim.lsp.diagn
 })
 
 -- Refs: https://github.com/neovim/nvim-lspconfig/wiki/UI-customization#show-source-in-diagnostics
-vim.lsp.handlers["textDocument/publishDiagnostics"] = function(_, _, params, client_id, _)
-  local uri = params.uri
-  local bufnr = vim.uri_to_bufnr(uri)
+vim.lsp.handlers["textDocument/publishDiagnostics"] = function(_, result, context, _)
+  -- result contains diagnostics and uri
+  -- context contains client_id and method, but not always buf_nr
+  local client_id = context.client_id
+  local diagnostics = result.diagnostics
+  local uri = result.uri
 
+  local bufnr = vim.uri_to_bufnr(uri)
   if not bufnr then
     return
   end
@@ -178,7 +182,7 @@ vim.lsp.handlers["textDocument/publishDiagnostics"] = function(_, _, params, cli
     return
   end
 
-  local diagnostics = params.diagnostics
+  -- change diagnostics format
   for i, v in ipairs(diagnostics) do
     diagnostics[i].message = string.format("%s: %s", v.source, v.message)
   end