From 4dfed34c1076c58949d1e895b7b229247939f8d6 Mon Sep 17 00:00:00 2001
From: Ching Pei Yang <badnam3o.0@gmail.com>
Date: Wed, 20 May 2026 16:20:48 +0200
Subject: [PATCH] lsp/lsp-signature: prevent error spam

---
 .../lsp/lsp-signature/lsp-signature.nix       | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/modules/plugins/lsp/lsp-signature/lsp-signature.nix b/modules/plugins/lsp/lsp-signature/lsp-signature.nix
index 45890180..2b843a6f 100644
--- a/modules/plugins/lsp/lsp-signature/lsp-signature.nix
+++ b/modules/plugins/lsp/lsp-signature/lsp-signature.nix
@@ -1,11 +1,40 @@
 {lib, ...}: let
-  inherit (lib.options) mkEnableOption;
-  inherit (lib.nvim.types) mkPluginSetupOption;
+  inherit (lib.options) mkEnableOption mkOption;
+  inherit (lib.nvim.types) mkPluginSetupOption luaInline;
+  inherit (lib.generators) mkLuaInline;
 in {
   options.vim.lsp = {
     lspSignature = {
       enable = mkEnableOption "lsp signature viewer";
-      setupOpts = mkPluginSetupOption "lsp-signature" {};
+      setupOpts = mkPluginSetupOption "lsp-signature" {
+        ignore_error = mkOption {
+          type = luaInline;
+          description = "Custom error filter.";
+          # https://github.com/NotAShelf/nvf/pull/1545#discussion_r3253920092
+          defaultText = "Filters out errors that occur more than once, per client";
+          default = mkLuaInline ''
+            function(err, ctx, config)
+              if ctx and ctx.client_id then
+                -- upstream default
+                local client = vim.lsp.get_client_by_id(ctx.client_id)
+                if client and vim.tbl_contains({"rust-analyzer", "clangd"}, client.name) then
+                  return true
+                end
+
+                -- prevents error spam
+                _LSP_SIG_IGNORE_ERR = _LSP_SIG_IGNORE_ERR or {}
+                _LSP_SIG_IGNORE_ERR[ctx.client_id] = _LSP_SIG_IGNORE_ERR[ctx.client_id]
+                  or {}
+                if _LSP_SIG_IGNORE_ERR[ctx.client_id][err.code] then
+                  return true
+                end
+
+                _LSP_SIG_IGNORE_ERR[ctx.client_id][err.code] = true
+              end
+            end
+          '';
+        };
+      };
     };
   };
 }