From 1eea4571449ced812a03f5d5658785bb16564c5e Mon Sep 17 00:00:00 2001
From: cmp-cmdline-fix <noreply@github.com>
Date: Wed, 5 Nov 2025 03:33:11 -0500
Subject: [PATCH] Fix: Handle vim.fn.getcompletion errors gracefully with pcall

vim.fn.getcompletion() can throw errors when the cmdline contains
malformed or incomplete patterns (e.g., unmatched braces like 'HEAD@{}',
incomplete regex patterns like '\(foo', etc).

This causes crashes with error messages like:
- E220: Missing }
- E54: Unmatched \(
- E869: Unknown operator

This fix wraps the getcompletion call with pcall to handle errors
gracefully, returning an empty completion list instead of crashing.

Fixes #73
Fixes #101
Related to #102
---
 lua/cmp_cmdline/init.lua | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/lua/cmp_cmdline/init.lua b/lua/cmp_cmdline/init.lua
index 53e7593..d69d860 100644
--- a/lua/cmp_cmdline/init.lua
+++ b/lua/cmp_cmdline/init.lua
@@ -133,15 +133,18 @@ local definitions = {
       --- create items.
       local items = {}
       local escaped = cmdline:gsub([[\\]], [[\\\\]]);
-      for _, word_or_item in ipairs(vim.fn.getcompletion(escaped, 'cmdline')) do
-        local word = type(word_or_item) == 'string' and word_or_item or word_or_item.word
-        local item = { label = word }
-        table.insert(items, item)
-        if is_option_name_completion and is_boolean_option(word) then
-          table.insert(items, vim.tbl_deep_extend('force', {}, item, {
-            label = 'no' .. word,
-            filterText = word,
-          }))
+      local ok, completions = pcall(vim.fn.getcompletion, escaped, 'cmdline')
+      if ok then
+        for _, word_or_item in ipairs(completions) do
+          local word = type(word_or_item) == 'string' and word_or_item or word_or_item.word
+          local item = { label = word }
+          table.insert(items, item)
+          if is_option_name_completion and is_boolean_option(word) then
+            table.insert(items, vim.tbl_deep_extend('force', {}, item, {
+              label = 'no' .. word,
+              filterText = word,
+            }))
+          end
         end
       end