Diagnostic

QUICKSTART diagnostic-quickstart

vim.diagnostic.get(0, { severity = vim.diagnostic.severity.WARN })

vim.diagnostic.get(0, { severity = { min = vim.diagnostic.severity.WARN } })

vim.diagnostic.get(0, { severity = {
    vim.diagnostic.severity.WARN,
    vim.diagnostic.severity.INFO,
} })

HANDLERS diagnostic-handlers

function(namespace, bufnr, diagnostics, opts)

function(namespace, bufnr)

-- It's good practice to namespace custom handlers to avoid collisions
vim.diagnostic.handlers["my/notify"] = {
  show = function(namespace, bufnr, diagnostics, opts)
    -- In our example, the opts table has a "log_level" option
    local level = opts["my/notify"].log_level
    local name = vim.diagnostic.get_namespace(namespace).name
    local msg = string.format("%d diagnostics in buffer %d from %s",
                              #diagnostics,
                              bufnr,
                              name)
    vim.notify(msg, level)
  end,
}
-- Users can configure the handler
vim.diagnostic.config({
  ["my/notify"] = {
    log_level = vim.log.levels.INFO,
    -- This handler will only receive "error" diagnostics.
    severity = vim.diagnostic.severity.ERROR,
  }
})

-- Create a custom namespace. This will aggregate signs from all other
-- namespaces and only show the one with the highest severity on a
-- given line
local ns = vim.api.nvim_create_namespace("my_namespace")
-- Get a reference to the original signs handler
local orig_signs_handler = vim.diagnostic.handlers.signs
-- Override the built-in signs handler
vim.diagnostic.handlers.signs = {
  show = function(_, bufnr, _, opts)
    -- Get all diagnostics from the whole buffer rather than just the
    -- diagnostics passed to the handler
    local diagnostics = vim.diagnostic.get(bufnr)
    -- Find the "worst" diagnostic per line
    local max_severity_per_line = {}
    for _, d in pairs(diagnostics) do
      local m = max_severity_per_line[d.lnum]
      if not m or d.severity < m.severity then
        max_severity_per_line[d.lnum] = d
      end
    end
    -- Pass the filtered diagnostics (with our custom namespace) to
    -- the original handler
    local filtered_diagnostics = vim.tbl_values(max_severity_per_line)
    orig_signs_handler.show(ns, bufnr, filtered_diagnostics, opts)
  end,
  hide = function(_, bufnr)
    orig_signs_handler.hide(ns, bufnr)
  end,
}

vim.keymap.set('n', 'gK', function()
  local new_config = not vim.diagnostic.config().virtual_lines
  vim.diagnostic.config({ virtual_lines = new_config })
end, { desc = 'Toggle diagnostic virtual_lines' })

vim.diagnostic.handlers.loclist = {
  show = function(_, _, _, opts)
    -- Generally don't want it to open on every update
    opts.loclist.open = opts.loclist.open or false
    local winid = vim.api.nvim_get_current_win()
    vim.diagnostic.setloclist(opts.loclist)
    vim.api.nvim_set_current_win(winid)
  end
}

-- Open the location list on every diagnostic change (warnings/errors only).
vim.diagnostic.config({
  loclist = {
    open = true,
    severity = { min = vim.diagnostic.severity.WARN },
  }
})

HIGHLIGHTS diagnostic-highlights

highlight DiagnosticError guifg="BrightRed"

SIGNS diagnostic-signs

-- Highlight entire line for errors
-- Highlight the line number for warnings
vim.diagnostic.config({
    signs = {
        text = {
            [vim.diagnostic.severity.ERROR] = '',
            [vim.diagnostic.severity.WARN] = '',
        },
        linehl = {
            [vim.diagnostic.severity.ERROR] = 'ErrorMsg',
        },
        numhl = {
            [vim.diagnostic.severity.WARN] = 'WarningMsg',
        },
    },
})

EVENTS diagnostic-events

vim.api.nvim_create_autocmd('DiagnosticChanged', {
  callback = function(args)
    local diagnostics = args.data.diagnostics
    vim.print(diagnostics)
  end,
})

Lua module: vim.diagnostic diagnostic-api

vim.diagnostic.config({ virtual_text = true })

vim.diagnostic.set(ns, 0, diagnostics, { virtual_text = false })

vim.diagnostic.enable(not vim.diagnostic.is_enabled())

WARNING filename:27:3: Variable 'foo' does not exist

local s = "WARNING filename:27:3: Variable 'foo' does not exist"
local pattern = "^(%w+) %w+:(%d+):(%d+): (.+)$"
local groups = { "severity", "lnum", "col", "message" }
vim.diagnostic.match(s, pattern, groups, { WARNING = vim.diagnostic.WARN })