refactor: move vim.lsp.diagnostic to vim.diagnostic

This generalizes diagnostic handling outside of just the scope of LSP.
LSP clients are now a specific case of a diagnostic producer, but the
diagnostic subsystem is decoupled from the LSP subsystem (or will be,
eventually).

More discussion at [1].

[1]: https://github.com/neovim/neovim/pull/15585

1 files changed, 368 insertions, 1101 deletions

diff --git a/runtime/lua/vim/lsp/diagnostic.lua b/runtime/lua/vim/lsp/diagnostic.lua
index ccd325b1ac..338491701f 100644
--- a/runtime/lua/vim/lsp/diagnostic.lua
+++ b/runtime/lua/vim/lsp/diagnostic.lua
@@ -1,48 +1,4 @@
-local api = vim.api
-local validate = vim.validate
-
-local highlight = vim.highlight
 local log = require('vim.lsp.log')
-local protocol = require('vim.lsp.protocol')
-local util = require('vim.lsp.util')
-
-local if_nil = vim.F.if_nil
-
----@class DiagnosticSeverity
-local DiagnosticSeverity = protocol.DiagnosticSeverity
-
-local to_severity = function(severity)
-  if not severity then return nil end
-  return type(severity) == 'string' and DiagnosticSeverity[severity] or severity
-end
-
-local filter_to_severity_limit = function(severity, diagnostics)
-  local filter_level = to_severity(severity)
-  if not filter_level then
-    return diagnostics
-  end
-
-  return vim.tbl_filter(function(t) return t.severity == filter_level end, diagnostics)
-end
-
-local filter_by_severity_limit = function(severity_limit, diagnostics)
-  local filter_level = to_severity(severity_limit)
-  if not filter_level then
-    return diagnostics
-  end
-
-  return vim.tbl_filter(function(t) return t.severity <= filter_level end, diagnostics)
-end
-
-local to_position = function(position, bufnr)
-  vim.validate { position = {position, 't'} }
-
-  return {
-    position.line,
-    util._get_line_byte_from_position(bufnr, position)
-  }
-end
-
 
 ---@brief lsp-diagnostic
 ---
@@ -57,70 +13,9 @@ end
 
 local M = {}
 
--- Diagnostic Highlights {{{
-
--- TODO(tjdevries): Determine how to generate documentation for these
---                  and how to configure them to be easy for users.
---
---                  For now, just use the following script. It should work pretty good.
---[[
-local levels = {"Error", "Warning", "Information", "Hint" }
-
-local all_info = {
-  { "Default", "Used as the base highlight group, other highlight groups link to", },
-  { "VirtualText", 'Used for "%s" diagnostic virtual text.\n  See |vim.lsp.diagnostic.set_virtual_text()|', },
-  { "Underline", 'Used to underline "%s" diagnostics.\n  See |vim.lsp.diagnostic.set_underline()|', },
-  { "Floating", 'Used to color "%s" diagnostic messages in diagnostics float.\n  See |vim.lsp.diagnostic.show_line_diagnostics()|', },
-  { "Sign", 'Used for "%s" signs in sing column.\n  See |vim.lsp.diagnostic.set_signs()|', },
-}
-
-local results = {}
-for _, info in ipairs(all_info) do
-  for _, level in ipairs(levels) do
-    local name = info[1]
-    local description = info[2]
-    local fullname = string.format("Lsp%s%s", name, level)
-    table.insert(results, string.format(
-      "%78s", string.format("*hl-%s*", fullname))
-    )
-
-    table.insert(results, fullname)
-    table.insert(results, string.format("  %s", description))
-    table.insert(results, "")
-  end
-end
-
--- print(table.concat(results, '\n'))
-vim.fn.setreg("*", table.concat(results, '\n'))
---]]
-
-local diagnostic_severities = {
-  [DiagnosticSeverity.Error]       = { guifg = "Red" };
-  [DiagnosticSeverity.Warning]     = { guifg = "Orange" };
-  [DiagnosticSeverity.Information] = { guifg = "LightBlue" };
-  [DiagnosticSeverity.Hint]        = { guifg = "LightGrey" };
-}
-
--- Make a map from DiagnosticSeverity -> Highlight Name
-local make_highlight_map = function(base_name)
-  local result = {}
-  for k, _ in pairs(diagnostic_severities) do
-    result[k] = "LspDiagnostics" .. base_name .. DiagnosticSeverity[k]
-  end
-
-  return result
-end
-
-local default_highlight_map = make_highlight_map("Default")
-local virtual_text_highlight_map = make_highlight_map("VirtualText")
-local underline_highlight_map = make_highlight_map("Underline")
-local floating_highlight_map = make_highlight_map("Floating")
-local sign_highlight_map = make_highlight_map("Sign")
-
--- }}}
--- Diagnostic Namespaces {{{
 local DEFAULT_CLIENT_ID = -1
-local get_client_id = function(client_id)
+---@private
+local function get_client_id(client_id)
   if client_id == nil then
     client_id = DEFAULT_CLIENT_ID
   end
@@ -128,179 +23,112 @@ local get_client_id = function(client_id)
   return client_id
 end
 
-local get_bufnr = function(bufnr)
+---@private
+local function get_bufnr(bufnr)
   if not bufnr then
-    return api.nvim_get_current_buf()
+    return vim.api.nvim_get_current_buf()
   elseif bufnr == 0 then
-    return api.nvim_get_current_buf()
+    return vim.api.nvim_get_current_buf()
   end
 
   return bufnr
 end
 
-
---- Create a namespace table, used to track a client's buffer local items
-local _make_namespace_table = function(namespace, api_namespace)
-  vim.validate { namespace = { namespace, 's' } }
-
-  return setmetatable({
-    [DEFAULT_CLIENT_ID] = api.nvim_create_namespace(namespace)
-  }, {
-    __index = function(t, client_id)
-      client_id = get_client_id(client_id)
-
-      if rawget(t, client_id) == nil then
-        local value = string.format("%s:%s", namespace, client_id)
-
-        if api_namespace then
-          value = api.nvim_create_namespace(value)
-        end
-
-        rawset(t, client_id, value)
-      end
-
-      return rawget(t, client_id)
-    end
-  })
-end
-
-local _diagnostic_namespaces = _make_namespace_table("vim_lsp_diagnostics", true)
-local _sign_namespaces = _make_namespace_table("vim_lsp_signs", false)
-
 ---@private
-function M._get_diagnostic_namespace(client_id)
-  return _diagnostic_namespaces[client_id]
+local function severity_lsp_to_vim(severity)
+  if type(severity) == 'string' then
+    severity = vim.lsp.protocol.DiagnosticSeverity[severity]
+  end
+  return severity
 end
 
 ---@private
-function M._get_sign_namespace(client_id)
-  return _sign_namespaces[client_id]
-end
--- }}}
--- Diagnostic Buffer & Client metatables {{{
-local bufnr_and_client_cacher_mt = {
-  __index = function(t, bufnr)
-    if bufnr == 0 or bufnr == nil then
-      bufnr = vim.api.nvim_get_current_buf()
-    end
-
-    if rawget(t, bufnr) == nil then
-      rawset(t, bufnr, {})
-    end
-
-    return rawget(t, bufnr)
-  end,
-
-  __newindex = function(t, bufnr, v)
-    if bufnr == 0 or bufnr == nil then
-      bufnr = vim.api.nvim_get_current_buf()
-    end
-
-    rawset(t, bufnr, v)
-  end,
-}
--- }}}
--- Diagnostic Saving & Caching {{{
-local _diagnostic_cleanup = setmetatable({}, bufnr_and_client_cacher_mt)
-local diagnostic_cache = setmetatable({}, bufnr_and_client_cacher_mt)
-local diagnostic_cache_extmarks = setmetatable({}, bufnr_and_client_cacher_mt)
-local diagnostic_cache_lines = setmetatable({}, bufnr_and_client_cacher_mt)
-local diagnostic_cache_counts = setmetatable({}, bufnr_and_client_cacher_mt)
-local diagnostic_attached_buffers = {}
-
--- Disabled buffers and clients
-local diagnostic_disabled = setmetatable({}, bufnr_and_client_cacher_mt)
-
-local _bufs_waiting_to_update = setmetatable({}, bufnr_and_client_cacher_mt)
-
---- Store Diagnostic[] by line
----
----@param diagnostics Diagnostic[]
----@return table<number, Diagnostic[]>
-local _diagnostic_lines = function(diagnostics)
-  if not diagnostics then return end
-
-  local diagnostics_by_line = {}
-  for _, diagnostic in ipairs(diagnostics) do
-    local start = diagnostic.range.start
-    local line_diagnostics = diagnostics_by_line[start.line]
-    if not line_diagnostics then
-      line_diagnostics = {}
-      diagnostics_by_line[start.line] = line_diagnostics
-    end
-    table.insert(line_diagnostics, diagnostic)
+local function severity_vim_to_lsp(severity)
+  if type(severity) == 'string' then
+    severity = vim.diagnostic.severity[severity]
   end
-  return diagnostics_by_line
+  return severity
 end
 
---- Get the count of M by Severity
----
----@param diagnostics Diagnostic[]
----@return table<DiagnosticSeverity, number>
-local _diagnostic_counts = function(diagnostics)
-  if not diagnostics then return end
-
-  local counts = {}
-  for _, diagnostic in pairs(diagnostics) do
-    if diagnostic.severity then
-      local val = counts[diagnostic.severity]
-      if val == nil then
-        val = 0
-      end
+---@private
+local function line_byte_from_position(lines, lnum, col, offset_encoding)
+  if offset_encoding == "utf-8" then
+    return col
+  end
 
-      counts[diagnostic.severity] = val + 1
-    end
+  local line = lines[lnum + 1]
+  local ok, result = pcall(vim.str_byteindex, line, col, offset_encoding == "utf-16")
+  if ok then
+    return result
   end
 
-  return counts
+  return col
 end
 
 ---@private
---- Set the different diagnostic cache after `textDocument/publishDiagnostics`
----@param diagnostics Diagnostic[]
----@param bufnr number
----@param client_id number
----@return nil
-local function set_diagnostic_cache(diagnostics, bufnr, client_id)
-  client_id = get_client_id(client_id)
-
-  -- https://microsoft.github.io/language-server-protocol/specifications/specification-current/#diagnostic
-  --
-  -- The diagnostic's severity. Can be omitted. If omitted it is up to the
-  -- client to interpret diagnostics as error, warning, info or hint.
-  -- TODO: Replace this with server-specific heuristics to infer severity.
-  local buf_line_count = vim.api.nvim_buf_line_count(bufnr)
-  for _, diagnostic in ipairs(diagnostics) do
-    if diagnostic.severity == nil then
-      diagnostic.severity = DiagnosticSeverity.Error
-    end
-    -- Account for servers that place diagnostics on terminating newline
-    if buf_line_count > 0 then
-      diagnostic.range.start.line = math.max(math.min(
-        diagnostic.range.start.line, buf_line_count - 1
-      ), 0)
-      diagnostic.range["end"].line = math.max(math.min(
-        diagnostic.range["end"].line, buf_line_count - 1
-      ), 0)
-    end
+local function get_buf_lines(bufnr)
+  if vim.api.nvim_buf_is_loaded(bufnr) then
+    return vim.api.nvim_buf_get_lines(bufnr, 0, -1, false)
   end
 
-  diagnostic_cache[bufnr][client_id] = diagnostics
-  diagnostic_cache_lines[bufnr][client_id] = _diagnostic_lines(diagnostics)
-  diagnostic_cache_counts[bufnr][client_id] = _diagnostic_counts(diagnostics)
+  local filename = vim.api.nvim_buf_get_name(bufnr)
+  local f = io.open(filename)
+  local lines = vim.split(f:read("*a"), "\n")
+  f:close()
+  return lines
 end
 
+---@private
+local function diagnostic_lsp_to_vim(diagnostics, bufnr, client_id)
+  local buf_lines = get_buf_lines(bufnr)
+  local client = vim.lsp.get_client_by_id(client_id)
+  local offset_encoding = client and client.offset_encoding or "utf-16"
+  return vim.tbl_map(function(diagnostic)
+    local start = diagnostic.range.start
+    local _end = diagnostic.range["end"]
+    return {
+      lnum = start.line,
+      col = line_byte_from_position(buf_lines, start.line, start.character, offset_encoding),
+      end_lnum = _end.line,
+      end_col = line_byte_from_position(buf_lines, _end.line, _end.character, offset_encoding),
+      severity = severity_lsp_to_vim(diagnostic.severity),
+      message = diagnostic.message
+    }
+  end, diagnostics)
+end
 
 ---@private
---- Clear the cached diagnostics
----@param bufnr number
----@param client_id number
-local function clear_diagnostic_cache(bufnr, client_id)
-  client_id = get_client_id(client_id)
+local function diagnostic_vim_to_lsp(diagnostics)
+  return vim.tbl_map(function(diagnostic)
+    return {
+      range = {
+        start = {
+          line = diagnostic.lnum,
+          character = diagnostic.col,
+        },
+        ["end"] = {
+          line = diagnostic.end_lnum,
+          character = diagnostic.end_col,
+        },
+      },
+      severity = severity_vim_to_lsp(diagnostic.severity),
+      message = diagnostic.message,
+    }
+  end, diagnostics)
+end
 
-  diagnostic_cache[bufnr][client_id] = nil
-  diagnostic_cache_lines[bufnr][client_id] = nil
-  diagnostic_cache_counts[bufnr][client_id] = nil
+local _client_namespaces = {}
+
+--- Get the diagnostic namespace associated with an LSP client |vim.diagnostic|.
+---
+---@param client_id number The id of the LSP client
+function M.get_namespace(client_id)
+  vim.validate { client_id = { client_id, 'n' } }
+  if not _client_namespaces[client_id] then
+    local name = string.format("vim.lsp.client-%d", client_id)
+    _client_namespaces[client_id] = vim.api.nvim_create_namespace(name)
+  end
+  return _client_namespaces[client_id]
 end
 
 --- Save diagnostics to the current buffer.
@@ -309,86 +137,146 @@ end
 ---@param diagnostics Diagnostic[]
 ---@param bufnr number
 ---@param client_id number
+---@private
 function M.save(diagnostics, bufnr, client_id)
-  validate {
-    diagnostics = {diagnostics, 't'},
-    bufnr = {bufnr, 'n'},
-    client_id = {client_id, 'n', true},
-  }
+  local namespace = M.get_namespace(client_id)
+  vim.diagnostic.set(namespace, bufnr, diagnostic_lsp_to_vim(diagnostics, bufnr, client_id))
+end
+-- }}}
+
+--- |lsp-handler| for the method "textDocument/publishDiagnostics"
+---
+--- See |vim.diagnostic.config()| for configuration options. Handler-specific
+--- configuration can be set using |vim.lsp.with()|:
+--- <pre>
+--- vim.lsp.handlers["textDocument/publishDiagnostics"] = vim.lsp.with(
+---   vim.lsp.diagnostic.on_publish_diagnostics, {
+---     -- Enable underline, use default values
+---     underline = true,
+---     -- Enable virtual text, override spacing to 4
+---     virtual_text = {
+---       spacing = 4,
+---     },
+---     -- Use a function to dynamically turn signs off
+---     -- and on, using buffer local variables
+---     signs = function(bufnr, client_id)
+---       return vim.bo[bufnr].show_signs == false
+---     end,
+---     -- Disable a feature
+---     update_in_insert = false,
+---   }
+--- )
+--- </pre>
+---
+---@param config table Configuration table (see |vim.diagnostic.config()|).
+function M.on_publish_diagnostics(_, result, ctx, config)
+  local client_id = ctx.client_id
+  local uri = result.uri
+  local bufnr = vim.uri_to_bufnr(uri)
 
-  if not diagnostics then return end
+  if not bufnr then
+    return
+  end
 
-  bufnr = get_bufnr(bufnr)
   client_id = get_client_id(client_id)
+  local namespace = M.get_namespace(client_id)
+  local diagnostics = result.diagnostics
 
-  if not _diagnostic_cleanup[bufnr][client_id] then
-    _diagnostic_cleanup[bufnr][client_id] = true
+  if config then
+    if vim.F.if_nil(config.severity_sort, false) then
+      table.sort(diagnostics, function(a, b) return a.severity > b.severity end)
+    end
 
-    -- Clean up our data when the buffer unloads.
-    api.nvim_buf_attach(bufnr, false, {
-      on_detach = function(_, b)
-        clear_diagnostic_cache(b, client_id)
-        _diagnostic_cleanup[b][client_id] = nil
+    for _, opt in pairs(config) do
+      if type(opt) == 'table' then
+        if not opt.severity and opt.severity_limit then
+          opt.severity = {min=severity_lsp_to_vim(opt.severity_limit)}
+        end
       end
-    })
+    end
+
+    vim.diagnostic.config(config, namespace)
   end
 
-  set_diagnostic_cache(diagnostics, bufnr, client_id)
+  vim.diagnostic.set(namespace, bufnr, diagnostic_lsp_to_vim(diagnostics, bufnr, client_id))
+
+  -- Keep old autocmd for back compat. This should eventually be removed.
+  vim.api.nvim_command("doautocmd <nomodeline> User LspDiagnosticsChanged")
+end
+
+--- Clear diagnotics and diagnostic cache.
+---
+--- Diagnostic producers should prefer |vim.diagnostic.reset()|. However,
+--- this method signature is still used internally in some parts of the LSP
+--- implementation so it's simply marked @private rather than @deprecated.
+---
+---@param client_id number
+---@param buffer_client_map table map of buffers to active clients
+---@private
+function M.reset(client_id, buffer_client_map)
+  buffer_client_map = vim.deepcopy(buffer_client_map)
+  vim.schedule(function()
+    for bufnr, client_ids in pairs(buffer_client_map) do
+      if client_ids[client_id] then
+        local namespace = M.get_namespace(client_id)
+        vim.diagnostic.reset(namespace, bufnr)
+      end
+    end
+  end)
 end
--- }}}
--- Diagnostic Retrieval {{{
 
+-- Deprecated Functions {{{
 
 --- Get all diagnostics for clients
 ---
+---@deprecated Prefer |vim.diagnostic.get()|
+---
 ---@param client_id number Restrict included diagnostics to the client
 ---                        If nil, diagnostics of all clients are included.
 ---@return table with diagnostics grouped by bufnr (bufnr: Diagnostic[])
 function M.get_all(client_id)
-  local diagnostics_by_bufnr = {}
-  for bufnr, buf_diagnostics in pairs(diagnostic_cache) do
-    diagnostics_by_bufnr[bufnr] = {}
-    for cid, client_diagnostics in pairs(buf_diagnostics) do
-      if client_id == nil or cid == client_id then
-        vim.list_extend(diagnostics_by_bufnr[bufnr], client_diagnostics)
-      end
-    end
+  local result = {}
+  local namespace
+  if client_id then
+    namespace = M.get_namespace(client_id)
+  end
+  for _, bufnr in ipairs(vim.api.nvim_list_bufs()) do
+    local diagnostics = diagnostic_vim_to_lsp(vim.diagnostic.get(bufnr, {namespace = namespace}))
+    result[bufnr] = diagnostics
   end
-  return diagnostics_by_bufnr
+  return result
 end
 
 --- Return associated diagnostics for bufnr
 ---
+---@deprecated Prefer |vim.diagnostic.get()|
+---
 ---@param bufnr number
 ---@param client_id number|nil If nil, then return all of the diagnostics.
 ---                            Else, return just the diagnostics associated with the client_id.
 ---@param predicate function|nil Optional function for filtering diagnostics
 function M.get(bufnr, client_id, predicate)
+  predicate = predicate or function() return true end
   if client_id == nil then
     local all_diagnostics = {}
-    for iter_client_id, _ in pairs(diagnostic_cache[bufnr]) do
-      local iter_diagnostics = M.get(bufnr, iter_client_id, predicate)
-
+    vim.lsp.for_each_buffer_client(bufnr, function(_, iter_client_id, _)
+      local iter_diagnostics = vim.tbl_filter(predicate, M.get(bufnr, iter_client_id))
       for _, diagnostic in ipairs(iter_diagnostics) do
         table.insert(all_diagnostics, diagnostic)
       end
-    end
-
-    return all_diagnostics
+    end)
+    return diagnostic_vim_to_lsp(all_diagnostics)
   end
 
-  predicate = predicate or function(_) return true end
-  local client_diagnostics = {}
-  for _, diagnostic in ipairs(diagnostic_cache[bufnr][client_id] or {}) do
-    if predicate(diagnostic) then
-      table.insert(client_diagnostics, diagnostic)
-    end
-  end
-  return client_diagnostics
+  local namespace = M.get_namespace(client_id)
+  return diagnostic_vim_to_lsp(vim.tbl_filter(predicate, vim.diagnostic.get(bufnr, {namespace=namespace})))
 end
 
 --- Get the diagnostics by line
 ---
+--- Marked private as this is used internally by the LSP subsystem, but
+--- most users should instead prefer |vim.diagnostic.get()|.
+---
 ---@param bufnr number|nil The buffer number
 ---@param line_nr number|nil The line number
 ---@param opts table|nil Configuration keys
@@ -398,216 +286,134 @@ end
 ---             - Limit severity of diagnostics found. E.g. "Warning" means { "Error", "Warning" } will be valid.
 ---@param client_id|nil number the client id
 ---@return table Table with map of line number to list of diagnostics.
---               Structured: { [1] = {...}, [5] = {.... } }
+---              Structured: { [1] = {...}, [5] = {.... } }
+---@private
 function M.get_line_diagnostics(bufnr, line_nr, opts, client_id)
   opts = opts or {}
-
-  bufnr = bufnr or vim.api.nvim_get_current_buf()
-  line_nr = line_nr or vim.api.nvim_win_get_cursor(0)[1] - 1
-
-  local client_get_diags = function(iter_client_id)
-    return (diagnostic_cache_lines[bufnr][iter_client_id] or {})[line_nr] or {}
+  if opts.severity then
+    opts.severity = severity_lsp_to_vim(opts.severity)
+  elseif opts.severity_limit then
+    opts.severity = {min=severity_lsp_to_vim(opts.severity_limit)}
   end
 
-  local line_diagnostics
-  if client_id == nil then
-    line_diagnostics = {}
-    for iter_client_id, _ in pairs(diagnostic_cache_lines[bufnr]) do
-      for _, diagnostic in ipairs(client_get_diags(iter_client_id)) do
-        table.insert(line_diagnostics, diagnostic)
-      end
-    end
-  else
-    line_diagnostics = vim.deepcopy(client_get_diags(client_id))
+  if client_id then
+    opts.namespace = M.get_namespace(client_id)
   end
 
-  if opts.severity then
-    line_diagnostics = filter_to_severity_limit(opts.severity, line_diagnostics)
-  elseif opts.severity_limit then
-    line_diagnostics = filter_by_severity_limit(opts.severity_limit, line_diagnostics)
+  if not line_nr then
+    line_nr = vim.api.nvim_win_get_cursor(0)[1] - 1
   end
 
-  table.sort(line_diagnostics, function(a, b) return a.severity < b.severity end)
+  opts.lnum = line_nr
 
-  return line_diagnostics
+  return diagnostic_vim_to_lsp(vim.diagnostic.get(bufnr, opts))
 end
 
 --- Get the counts for a particular severity
 ---
---- Useful for showing diagnostic counts in statusline. eg:
----
---- <pre>
---- function! LspStatus() abort
----   let sl = ''
----   if luaeval('not vim.tbl_isempty(vim.lsp.buf_get_clients(0))')
----     let sl.='%#MyStatuslineLSP#E:'
----     let sl.='%#MyStatuslineLSPErrors#%{luaeval("vim.lsp.diagnostic.get_count(0, [[Error]])")}'
----     let sl.='%#MyStatuslineLSP# W:'
----     let sl.='%#MyStatuslineLSPWarnings#%{luaeval("vim.lsp.diagnostic.get_count(0, [[Warning]])")}'
----   else
----       let sl.='%#MyStatuslineLSPErrors#off'
----   endif
----   return sl
---- endfunction
---- autocmd BufWinEnter * let &l:statusline = '%#MyStatuslineLSP#LSP '.LspStatus()
---- </pre>
+---@deprecated Prefer |vim.diagnostic.get_count()|
 ---
 ---@param bufnr number The buffer number
 ---@param severity DiagnosticSeverity
 ---@param client_id number the client id
 function M.get_count(bufnr, severity, client_id)
-  if client_id == nil then
-    local total = 0
-    for iter_client_id, _ in pairs(diagnostic_cache_counts[bufnr]) do
-      total = total + M.get_count(bufnr, severity, iter_client_id)
-    end
-
-    return total
-  end
-
-  return (diagnostic_cache_counts[bufnr][client_id] or {})[DiagnosticSeverity[severity]] or 0
-end
-
-
--- }}}
--- Diagnostic Movements {{{
-
---- Helper function to find the next diagnostic relative to a position
----@return table the next diagnostic if found
-local _next_diagnostic = function(position, search_forward, bufnr, opts, client_id)
-  position[1] = position[1] - 1
-  bufnr = bufnr or vim.api.nvim_get_current_buf()
-  local wrap = if_nil(opts.wrap, true)
-  local line_count = vim.api.nvim_buf_line_count(bufnr)
-  for i = 0, line_count do
-    local offset = i * (search_forward and 1 or -1)
-    local line_nr = position[1] + offset
-    if line_nr < 0 or line_nr >= line_count then
-      if not wrap then
-        return
-      end
-      line_nr = (line_nr + line_count) % line_count
-    end
-    local line_diagnostics = M.get_line_diagnostics(bufnr, line_nr, opts, client_id)
-    if line_diagnostics and not vim.tbl_isempty(line_diagnostics) then
-      local sort_diagnostics, is_next
-      if search_forward then
-        sort_diagnostics = function(a, b) return a.range.start.character < b.range.start.character end
-        is_next = function(diagnostic) return diagnostic.range.start.character > position[2] end
-      else
-        sort_diagnostics = function(a, b) return a.range.start.character > b.range.start.character end
-        is_next = function(diagnostic) return diagnostic.range.start.character < position[2] end
-      end
-      table.sort(line_diagnostics, sort_diagnostics)
-      if i == 0 then
-        for _, v in pairs(line_diagnostics) do
-          if is_next(v) then
-            return v
-          end
-        end
-      else
-        return line_diagnostics[1]
-      end
-    end
-  end
-end
-
----@private
---- Helper function to return a position from a diagnostic
----
----@return table {row, col}
-local function _diagnostic_pos(opts, diagnostic)
-  opts = opts or {}
-
-  local win_id = opts.win_id or vim.api.nvim_get_current_win()
-  local bufnr = vim.api.nvim_win_get_buf(win_id)
-
-  if not diagnostic then return false end
-
-  return to_position(diagnostic.range.start, bufnr)
-end
-
----@private
--- Move to the diagnostic position
-local function _diagnostic_move_pos(name, opts, pos)
-  opts = opts or {}
-
-  local enable_popup = if_nil(opts.enable_popup, true)
-  local win_id = opts.win_id or vim.api.nvim_get_current_win()
-
-  if not pos then
-    print(string.format("%s: No more valid diagnostics to move to.", name))
-    return
+  severity = severity_lsp_to_vim(severity)
+  local opts = { severity = severity }
+  if client_id ~= nil then
+    opts.namespace = M.get_namespace(client_id)
   end
 
-  vim.api.nvim_win_set_cursor(win_id, {pos[1] + 1, pos[2]})
-
-  if enable_popup then
-    -- This is a bit weird... I'm surprised that we need to wait til the next tick to do this.
-    vim.schedule(function()
-      M.show_position_diagnostics(opts.popup_opts, vim.api.nvim_win_get_buf(win_id))
-    end)
-  end
+  return #vim.diagnostic.get(bufnr, opts)
 end
 
 --- Get the previous diagnostic closest to the cursor_position
 ---
+---@deprecated Prefer |vim.diagnostic.get_prev()|
+---
 ---@param opts table See |vim.lsp.diagnostic.goto_next()|
 ---@return table Previous diagnostic
 function M.get_prev(opts)
-  opts = opts or {}
-
-  local win_id = opts.win_id or vim.api.nvim_get_current_win()
-  local bufnr = vim.api.nvim_win_get_buf(win_id)
-  local cursor_position = opts.cursor_position or vim.api.nvim_win_get_cursor(win_id)
-
-  return _next_diagnostic(cursor_position, false, bufnr, opts, opts.client_id)
+  if opts then
+    if opts.severity then
+      opts.severity = severity_lsp_to_vim(opts.severity)
+    elseif opts.severity_limit then
+      opts.severity = {min=severity_lsp_to_vim(opts.severity_limit)}
+    end
+  end
+  return diagnostic_vim_to_lsp({vim.diagnostic.get_prev(opts)})[1]
 end
 
 --- Return the pos, {row, col}, for the prev diagnostic in the current buffer.
+---
+---@deprecated Prefer |vim.diagnostic.get_prev_pos()|
+---
 ---@param opts table See |vim.lsp.diagnostic.goto_next()|
 ---@return table Previous diagnostic position
 function M.get_prev_pos(opts)
-  return _diagnostic_pos(
-    opts,
-    M.get_prev(opts)
-  )
+  if opts then
+    if opts.severity then
+      opts.severity = severity_lsp_to_vim(opts.severity)
+    elseif opts.severity_limit then
+      opts.severity = {min=severity_lsp_to_vim(opts.severity_limit)}
+    end
+  end
+  return vim.diagnostic.get_prev_pos(opts)
 end
 
 --- Move to the previous diagnostic
+---
+---@deprecated Prefer |vim.diagnostic.goto_prev()|
+---
 ---@param opts table See |vim.lsp.diagnostic.goto_next()|
 function M.goto_prev(opts)
-  return _diagnostic_move_pos(
-    "DiagnosticPrevious",
-    opts,
-    M.get_prev_pos(opts)
-  )
+  if opts then
+    if opts.severity then
+      opts.severity = severity_lsp_to_vim(opts.severity)
+    elseif opts.severity_limit then
+      opts.severity = {min=severity_lsp_to_vim(opts.severity_limit)}
+    end
+  end
+  return vim.diagnostic.goto_prev(opts)
 end
 
 --- Get the next diagnostic closest to the cursor_position
+---
+---@deprecated Prefer |vim.diagnostic.get_next()|
+---
 ---@param opts table See |vim.lsp.diagnostic.goto_next()|
 ---@return table Next diagnostic
 function M.get_next(opts)
-  opts = opts or {}
-
-  local win_id = opts.win_id or vim.api.nvim_get_current_win()
-  local bufnr = vim.api.nvim_win_get_buf(win_id)
-  local cursor_position = opts.cursor_position or vim.api.nvim_win_get_cursor(win_id)
-
-  return _next_diagnostic(cursor_position, true, bufnr, opts, opts.client_id)
+  if opts then
+    if opts.severity then
+      opts.severity = severity_lsp_to_vim(opts.severity)
+    elseif opts.severity_limit then
+      opts.severity = {min=severity_lsp_to_vim(opts.severity_limit)}
+    end
+  end
+  return diagnostic_vim_to_lsp({vim.diagnostic.get_next(opts)})[1]
 end
 
 --- Return the pos, {row, col}, for the next diagnostic in the current buffer.
+---
+---@deprecated Prefer |vim.diagnostic.get_next_pos()|
+---
 ---@param opts table See |vim.lsp.diagnostic.goto_next()|
 ---@return table Next diagnostic position
 function M.get_next_pos(opts)
-  return _diagnostic_pos(
-    opts,
-    M.get_next(opts)
-  )
+  if opts then
+    if opts.severity then
+      opts.severity = severity_lsp_to_vim(opts.severity)
+    elseif opts.severity_limit then
+      opts.severity = {min=severity_lsp_to_vim(opts.severity_limit)}
+    end
+  end
+  return vim.diagnostic.get_next_pos(opts)
 end
 
 --- Move to the next diagnostic
+---
+---@deprecated Prefer |vim.diagnostic.goto_next()|
+---
 ---@param opts table|nil Configuration table. Keys:
 ---         - {client_id}: (number)
 ---             - If nil, will consider all clients attached to buffer.
@@ -626,17 +432,20 @@ end
 ---         - {win_id}: (number, default 0)
 ---             - Window ID
 function M.goto_next(opts)
-  return _diagnostic_move_pos(
-    "DiagnosticNext",
-    opts,
-    M.get_next_pos(opts)
-  )
+  if opts then
+    if opts.severity then
+      opts.severity = severity_lsp_to_vim(opts.severity)
+    elseif opts.severity_limit then
+      opts.severity = {min=severity_lsp_to_vim(opts.severity_limit)}
+    end
+  end
+  return vim.diagnostic.goto_next(opts)
 end
--- }}}
--- Diagnostic Setters {{{
 
 --- Set signs for given diagnostics
 ---
+---@deprecated Prefer |vim.diagnostic._set_signs()|
+---
 --- Sign characters can be customized with the following commands:
 ---
 --- <pre>
@@ -654,35 +463,12 @@ end
 ---             - severity_limit (DiagnosticSeverity):
 ---                 - Limit severity of diagnostics found. E.g. "Warning" means { "Error", "Warning" } will be valid.
 function M.set_signs(diagnostics, bufnr, client_id, sign_ns, opts)
-  opts = opts or {}
-  sign_ns = sign_ns or M._get_sign_namespace(client_id)
-
-  if not diagnostics then
-    diagnostics = diagnostic_cache[bufnr][client_id]
-  end
-
-  if not diagnostics then
-    return
-  end
-
-  bufnr = get_bufnr(bufnr)
-  diagnostics = filter_by_severity_limit(opts.severity_limit, diagnostics)
-
-  local ok = true
-  for _, diagnostic in ipairs(diagnostics) do
-
-    ok = ok and pcall(vim.fn.sign_place,
-      0,
-      sign_ns,
-      sign_highlight_map[diagnostic.severity],
-      bufnr,
-      {
-        priority = opts.priority,
-        lnum = diagnostic.range.start.line + 1
-      }
-    )
+  local namespace = M.get_namespace(client_id)
+  if opts and not opts.severity and opts.severity_limit then
+    opts.severity = {min=severity_lsp_to_vim(opts.severity_limit)}
   end
 
+  local ok = vim.diagnostic._set_signs(namespace, bufnr, diagnostic_lsp_to_vim(diagnostics, bufnr, client_id), opts)
   if not ok then
     log.debug("Failed to place signs:", diagnostics)
   end
@@ -690,6 +476,8 @@ end
 
 --- Set underline for given diagnostics
 ---
+---@deprecated Prefer |vim.diagnostic._set_underline()|
+---
 --- Underline highlights can be customized by changing the following |:highlight| groups.
 ---
 --- <pre>
@@ -707,34 +495,17 @@ end
 ---             - severity_limit (DiagnosticSeverity):
 ---                 - Limit severity of diagnostics found. E.g. "Warning" means { "Error", "Warning" } will be valid.
 function M.set_underline(diagnostics, bufnr, client_id, diagnostic_ns, opts)
-  opts = opts or {}
-
-  diagnostic_ns = diagnostic_ns or M._get_diagnostic_namespace(client_id)
-  diagnostics = filter_by_severity_limit(opts.severity_limit, diagnostics)
-
-  for _, diagnostic in ipairs(diagnostics) do
-    local start = diagnostic.range["start"]
-    local finish = diagnostic.range["end"]
-    local higroup = underline_highlight_map[diagnostic.severity]
-
-    if higroup == nil then
-      -- Default to error if we don't have a highlight associated
-      higroup = underline_highlight_map[DiagnosticSeverity.Error]
-    end
-
-    highlight.range(
-      bufnr,
-      diagnostic_ns,
-      higroup,
-      to_position(start, bufnr),
-      to_position(finish, bufnr)
-    )
+  local namespace = M.get_namespace(client_id)
+  if opts and not opts.severity and opts.severity_limit then
+    opts.severity = {min=severity_lsp_to_vim(opts.severity_limit)}
   end
+  return vim.diagnostic._set_underline(namespace, bufnr, diagnostic_lsp_to_vim(diagnostics, bufnr, client_id), opts)
 end
 
--- Virtual Text {{{
 --- Set virtual text given diagnostics
 ---
+---@deprecated Prefer |vim.diagnostic._set_virtual_text()|
+---
 --- Virtual text highlights can be customized by changing the following |:highlight| groups.
 ---
 --- <pre>
@@ -754,35 +525,17 @@ end
 ---             - severity_limit (DiagnosticSeverity):
 ---                 - Limit severity of diagnostics found. E.g. "Warning" means { "Error", "Warning" } will be valid.
 function M.set_virtual_text(diagnostics, bufnr, client_id, diagnostic_ns, opts)
-  opts = opts or {}
-
-  client_id = get_client_id(client_id)
-  diagnostic_ns = diagnostic_ns or M._get_diagnostic_namespace(client_id)
-
-  local buffer_line_diagnostics
-  if diagnostics then
-    buffer_line_diagnostics = _diagnostic_lines(diagnostics)
-  else
-    buffer_line_diagnostics = diagnostic_cache_lines[bufnr][client_id]
-  end
-
-  if not buffer_line_diagnostics then
-    return nil
-  end
-
-  for line, line_diagnostics in pairs(buffer_line_diagnostics) do
-    line_diagnostics = filter_by_severity_limit(opts.severity_limit, line_diagnostics)
-    local virt_texts = M.get_virtual_text_chunks_for_line(bufnr, line, line_diagnostics, opts)
-
-    if virt_texts then
-      api.nvim_buf_set_extmark(bufnr, diagnostic_ns, line, 0, {
-        virt_text = virt_texts,
-      })
-    end
+  local namespace = M.get_namespace(client_id)
+  if opts and not opts.severity and opts.severity_limit then
+    opts.severity = {min=severity_lsp_to_vim(opts.severity_limit)}
   end
+  return vim.diagnostic._set_virtual_text(namespace, bufnr, diagnostic_lsp_to_vim(diagnostics, bufnr, client_id), opts)
 end
 
 --- Default function to get text chunks to display using |nvim_buf_set_extmark()|.
+---