Commenting using `gc` loads copilot-chat syntax in unrelated markdown buffers

[liskin]

Reproducer:

1. nvim x.md
2. add two lines:

   a/b
   x
   

3. go to the "x" line and comment it using the gc mapping
4. observe that "/b" is suddenly highlighted as CopilotChatPrompt despite this being a normal markdown buffer

Cause:

CopilotChat.nvim/plugin/CopilotChat.lua

Line 127 in 2025f92

vim.treesitter.language.register('markdown', 'copilot-chat')

CopilotChat.nvim/plugin/CopilotChat.lua

Lines 39 to 49 in 2025f92

	vim.api.nvim_create_autocmd('FileType', {
	pattern = 'copilot-chat',
	group = group,
	callback = vim.schedule_wrap(function()
	vim.cmd.syntax('match CopilotChatResource "#\\S\\+"')
	vim.cmd.syntax('match CopilotChatTool "@\\S\\+"')
	vim.cmd.syntax('match CopilotChatPrompt "/\\S\\+"')
	vim.cmd.syntax('match CopilotChatModel "\\$\\S\\+"')
	vim.cmd.syntax('match CopilotChatUri "##\\S\\+"')
	end),
	})

https://github.com/neovim/neovim/blob/release-0.12/runtime/lua/vim/_comment.lua#L47-L49

vim.filetype.get_option triggers FileType autocommands the first time it's called for a given filetype, so the first markdown buffer where gc is used will have syntax rules for copilot-chat unfortunately.

One might argue that this is a neovim bug actually - using all filetypes associated with markdown, even if we know the exact filetype in that buffer, seems quite stupid. I'm not sure what the right way to fix this is, yet.

[liskin]

Oh, actually, I think it's the vim.schedule_wrap in plugin/CopilotChat.lua that causes this. nvim_get_option_value correctly creates a separate buffer to avoid this, but CopilotChat's vim.schedule_wrap breaks this. 100% a CopilotChat bug then.

[liskin]

A crude workaround:

diff --git ./plugin/CopilotChat.lua ./plugin/CopilotChat.lua
index db83d5b..eb60b18 100644
--- ./plugin/CopilotChat.lua
+++ ./plugin/CopilotChat.lua
@@ -39,13 +39,19 @@ setup_highlights()
 vim.api.nvim_create_autocmd('FileType', {
   pattern = 'copilot-chat',
   group = group,
-  callback = vim.schedule_wrap(function()
-    vim.cmd.syntax('match CopilotChatResource "#\\S\\+"')
-    vim.cmd.syntax('match CopilotChatTool "@\\S\\+"')
-    vim.cmd.syntax('match CopilotChatPrompt "/\\S\\+"')
-    vim.cmd.syntax('match CopilotChatModel "\\$\\S\\+"')
-    vim.cmd.syntax('match CopilotChatUri "##\\S\\+"')
-  end),
+  callback = function()
+    local bufnr = vim.api.nvim_get_current_buf()
+    vim.schedule(function()
+      -- nvim_get_option_value workaround
+      if bufnr ~= vim.api.nvim_get_current_buf() then return end
+
+      vim.cmd.syntax('match CopilotChatResource "#\\S\\+"')
+      vim.cmd.syntax('match CopilotChatTool "@\\S\\+"')
+      vim.cmd.syntax('match CopilotChatPrompt "/\\S\\+"')
+      vim.cmd.syntax('match CopilotChatModel "\\$\\S\\+"')
+      vim.cmd.syntax('match CopilotChatUri "##\\S\\+"')
+    end)
+  end,
 })
 
 -- Setup commands

I hope a better solution exists but this works for now.