fix(diagnostics): add fallback to signs on nvim v0.10+ (#1741)

Author: pynappo

README.md

@@ -158,7 +158,21 @@ return {
     -----@type neotree.Config
     --opts = {},
     config = function()
-      -- If you want icons for diagnostic errors, you'll need to define them somewhere:
+      -- If you want icons for diagnostic errors, you'll need to define them somewhere.
+      -- In Neovim v0.10+, you can configure them in vim.diagnostic.config(), like:
+      --
+      -- vim.diagnostic.config({
+      --   signs = {
+      --     text = {
+      --       [vim.diagnostic.severity.ERROR] = '',
+      --       [vim.diagnostic.severity.WARN] = '',
+      --       [vim.diagnostic.severity.INFO] = '',
+      --       [vim.diagnostic.severity.HINT] = '󰌵',
+      --     },
+      --   }
+      -- })
+      --
+      -- In older versions, you can define the signs manually:
       -- vim.fn.sign_define("DiagnosticSignError", { text = " ", texthl = "DiagnosticSignError" })
       -- vim.fn.sign_define("DiagnosticSignWarn", { text = " ", texthl = "DiagnosticSignWarn" })
       -- vim.fn.sign_define("DiagnosticSignInfo", { text = " ", texthl = "DiagnosticSignInfo" })

doc/neo-tree.txt

@@ -1183,6 +1183,29 @@ display the highest severity level for files, and errors only for directories.
 If you want to use symbols instead of "E", "W", "I", and H", you'll need to
 define those somewhere in your nvim configuration. Here is an example:
 
+>lua
+    vim.diagnostic.config({
+      signs = {
+        text = {
+          [vim.diagnostic.severity.ERROR] = '',
+          [vim.diagnostic.severity.WARN] = '',
+          [vim.diagnostic.severity.INFO] = '',
+          [vim.diagnostic.severity.HINT] = '󰌵',
+        },
+      }
+    })
+<
+
+If you don't change the `signs` option from its default, e.g.:
+
+>lua
+    vim.diagnostic.config({
+      signs = true
+    })
+<
+
+or are on Neovim v0.9 and below, then this will work instead:
+
 >lua
     vim.fn.sign_define("DiagnosticSignError",
         {text = " ", texthl = "DiagnosticSignError"})
@@ -1216,7 +1239,8 @@ neo-tree setup call like this:
         },
       }
     })
->
+<
+
 Anything not specified in the `default_component_configs` will fallback to the
 `sign_define` method.
 

lua/neo-tree/sources/common/components.lua

@@ -120,40 +120,61 @@ end
 ---`sign_getdefined` based wrapper with compatibility
 ---@param severity string
 ---@return vim.fn.sign_getdefined.ret.item
-local function get_defined_sign(severity)
-  local defined
+local get_legacy_sign = function(severity)
+  local sign = vim.fn.sign_getdefined("DiagnosticSign" .. severity)
+  if vim.tbl_isempty(sign) then
+    -- backwards compatibility...
+    local old_severity = severity
+    if severity == "Warning" then
+      old_severity = "Warn"
+    elseif severity == "Information" then
+      old_severity = "Info"
+    end
+    sign = vim.fn.sign_getdefined("LspDiagnosticsSign" .. old_severity)
+  end
+  return sign and sign[1]
+end
+
+local nvim_0_10 = vim.fn.has("nvim-0.10") > 0
+---Returns the sign corresponding to the given severity
+---@param severity string
+---@return vim.fn.sign_getdefined.ret.item
+local function get_diagnostic_sign(severity)
+  local sign
+
+  if nvim_0_10 then
+    local signs = vim.diagnostic.config().signs
+
+    if type(signs) == "function" then
+      --TODO: Find a better way to get a namespace
+      local namespaces = vim.diagnostic.get_namespaces()
+      if not vim.tbl_isempty(namespaces) then
+        local ns_id = next(namespaces)
+        ---@cast ns_id -nil
+        signs = signs(ns_id, 0)
+      end
+    end
 
-  if vim.fn.has("nvim-0.10") > 0 then
-    local signs_config = vim.diagnostic.config().signs
-    if type(signs_config) == "table" then
+    if type(signs) == "table" then
       local identifier = severity:sub(1, 1)
       if identifier == "H" then
         identifier = "N"
       end
-      defined = {
-        text = (signs_config.text or {})[vim.diagnostic.severity[identifier]],
+      sign = {
+        text = (signs.text or {})[vim.diagnostic.severity[identifier]],
         texthl = "DiagnosticSign" .. severity,
       }
+    elseif signs == true then
+      sign = get_legacy_sign(severity)
     end
   else -- before 0.10
-    defined = vim.fn.sign_getdefined("DiagnosticSign" .. severity)
-    if vim.tbl_isempty(defined) then
-      -- backwards compatibility...
-      local old_severity = severity
-      if severity == "Warning" then
-        old_severity = "Warn"
-      elseif severity == "Information" then
-        old_severity = "Info"
-      end
-      defined = vim.fn.sign_getdefined("LspDiagnosticsSign" .. old_severity)
-    end
-    defined = defined and defined[1]
+    sign = get_legacy_sign(severity)
   end
 
-  if type(defined) ~= "table" then
-    defined = {}
+  if type(sign) ~= "table" then
+    sign = {}
   end
-  return defined
+  return sign
 end
 
 ---@class (exact) neotree.Component.Common.Diagnostics : neotree.Component
@@ -178,23 +199,23 @@ M.diagnostics = function(config, node, state)
   end
   ---@type string
   local severity = diag_state.severity_string
-  local defined = get_defined_sign(severity)
+  local sign = get_diagnostic_sign(severity)
 
   -- check for overrides in the component config
   local severity_lower = severity:lower()
   if config.symbols and config.symbols[severity_lower] then
-    defined.texthl = defined.texthl or ("Diagnostic" .. severity)
-    defined.text = config.symbols[severity_lower]
+    sign.texthl = sign.texthl or ("Diagnostic" .. severity)
+    sign.text = config.symbols[severity_lower]
   end
   if config.highlights and config.highlights[severity_lower] then
-    defined.text = defined.text or severity:sub(1, 1)
-    defined.texthl = config.highlights[severity_lower]
+    sign.text = sign.text or severity:sub(1, 1)
+    sign.texthl = config.highlights[severity_lower]
   end
 
-  if defined.text and defined.texthl then
+  if sign.text and sign.texthl then
     return {
-      text = make_two_char(defined.text),
-      highlight = defined.texthl,
+      text = make_two_char(sign.text),
+      highlight = sign.texthl,
     }
   else
     return {