feat: add custom icons to language server diagnostics

lua/config/icons.lua

@@ -0,0 +1,20 @@
+
+--
+-- Icons
+--
+-- ..............................................
+--
+-- Author: Sven Vogel
+-- Created: 08.11.2024
+-- Edited: 08.11.2024
+--
+-- ==============================================
+
+return {
+    diagnostics = {
+        error = "",
+        warn = "",
+        hint = "",
+        info = ""
+    }
+}

lua/plugins/nvim-lspconfig.lua

@@ -12,6 +12,7 @@
 -- ==============================================
 
 ui = require 'config.ui'
+icons = require 'config.icons'
 
 return {
     {
@@ -29,8 +30,6 @@ return {
                 enabled = true,
             },
             diagnostics = {
-                virtual_text = true,
-                signs = true,
                 update_in_insert = false,
                 underline = true,
                 severity_sort = false,
@@ -38,9 +37,24 @@ return {
                     border = ui.border,
                     source = 'always',
                 },
+                virtual_text = {
+                    spacing = 4,
+                    source = "if_many",
+                    -- this will set set the prefix to a function that returns the diagnostics icon based on the severity
+                    -- this only works on a recent 0.10.0 build. Will be set to "●" when not supported
+                    prefix = "icons"
+                },
+                signs = {
+                    text = {
+                        [vim.diagnostic.severity.ERROR] = icons.diagnostics.error,
+                        [vim.diagnostic.severity.WARN] = icons.diagnostics.warn,
+                        [vim.diagnostic.severity.HINT] = icons.diagnostics.hint,
+                        [vim.diagnostic.severity.INFO] = icons.diagnostics.info
+                    }
+                }
             }
         },
-        config = function(opts)
+        config = function(_, opts)
             require("mason").setup()
 
             local handlers = {
@@ -57,6 +71,31 @@ return {
 
             require("mason-lspconfig").setup({ handlers = handlers })
 
+            -- Setup diagnostic signs
+            --
+            -- Source: https://www.lazyvim.org/plugins/lsp#mason-lspconfignvim
+            -- ..............................................
+
+            -- diagnostics signs
+            if type(opts.diagnostics.signs) ~= "boolean" then
+                for severity, icon in pairs(opts.diagnostics.signs.text) do
+                    local name = vim.diagnostic.severity[severity]:lower():gsub("^%l", string.upper)
+                    name = "DiagnosticSign" .. name
+                    vim.fn.sign_define(name, { text = icon, texthl = name, numhl = "" })
+                end
+            end
+
+            -- diagnostic sign as prefix for virtual text
+            if type(opts.diagnostics.virtual_text) == "table" and opts.diagnostics.virtual_text.prefix == "icons" then
+                opts.diagnostics.virtual_text.prefix = vim.fn.has("nvim-0.10.0") == 0 and "●" or function(diagnostic)
+                    for d, icon in pairs(icons.diagnostics) do
+                        if diagnostic.severity == vim.diagnostic.severity[d:upper()] then
+                            return icon
+                        end
+                    end
+                end
+            end
+
             -- Setup diagnostic user interface
             --
             -- Source: https://vonheikemen.github.io/devlog/tools/setup-nvim-lspconfig-plus-nvim-cmp