Neovim Slow With Large Files? Fix Blink.pairs Issue

Experiencing performance issues with Neovim when working with large files, even after disabling blink.pairs? You're not alone. Many users have encountered slowdowns and freezes, especially when scrolling through large files. This article delves into a specific issue related to the blink.pairs plugin and provides steps to diagnose and potentially resolve the problem. Let's explore the depths of this issue and find a solution that brings back the smooth performance you expect from Neovim. We will cover everything from identifying the problem, understanding the configuration, and potential fixes to make your Neovim experience seamless again.

Understanding the Neovim Slowdown with Large Files

When dealing with large files in Neovim, performance can sometimes take a hit. Identifying the cause is the first step to resolving the issue. In this case, users have reported significant slowdowns even after attempting to disable the blink.pairs plugin, which is designed to highlight matching pairs of characters like parentheses and brackets. The slowdown typically manifests as lag when scrolling through the file or when making edits. This can be incredibly frustrating, especially when working on projects with extensive codebases or large datasets. It's crucial to pinpoint whether the problem genuinely stems from blink.pairs or if other factors are at play, such as other plugins, Neovim configuration, or system resource limitations.

The core issue reported is that despite setting vim.b.pairs = false or adding the filetype to disabled_filetypes, the slowdown persists. This suggests that the plugin might still be active or that some residual functionality is affecting performance. To confirm this, users have tried disabling the plugin entirely through their plugin manager (e.g., lazy.nvim) and observing whether the slowdown disappears. If disabling the plugin resolves the issue, it strongly indicates that blink.pairs is indeed the culprit. The challenge then becomes understanding why the intended disabling methods are not working as expected. This might involve examining the plugin's configuration, Neovim's autocommand settings, and the interaction between blink.pairs and other installed plugins.

Diagnosing the Issue: Steps to Reproduce

To accurately diagnose the problem, following a consistent set of steps is essential. Here’s a breakdown of how to reproduce the slowdown:

1. Install blink.pairs via a plugin manager: Use a plugin manager like lazy.nvim to install the blink.pairs plugin. This ensures that the plugin is correctly set up and managed within your Neovim environment.
2. Attempt to disable blink.pairs: There are two primary methods to disable the plugin: either by setting vim.b.pairs = false in a BufReadPre autocmd or by adding the relevant filetype to the mappings.disabled_filetypes configuration within the plugin's settings. The goal here is to prevent the plugin from activating for specific files or filetypes.
3. Open a large file: Open a file that is significantly large (e.g., 100 MB or more). The size of the file is critical because the slowdown is more noticeable with larger files due to the increased processing load.
4. Scroll through the file: Use navigation keys like hjkl or <C-u> and <C-d> to scroll through the file. Pay attention to any lag or freezes that occur during scrolling. Repeatedly pressing the scroll keys can help accentuate the slowdown.
5. Disable the plugin entirely: If the slowdown is observed, disable blink.pairs directly through your plugin manager. This completely removes the plugin from Neovim's active plugins.
6. Repeat the scrolling test: After disabling the plugin, repeat the scrolling test on the same large file. If the slowdown disappears, it confirms that blink.pairs was indeed the cause.

By following these steps, you can consistently reproduce the issue and verify whether the attempted disabling methods are effective. This diagnostic process is crucial for understanding the root cause and implementing the correct solution.

Configuration and Relevant Settings

The configuration settings for blink.pairs play a crucial role in its behavior, and understanding these settings is key to troubleshooting performance issues. The user in this scenario has provided their configuration, which offers valuable insights into how the plugin is set up and where potential conflicts might arise.

Here’s a breakdown of the relevant configuration:

• Plugin Manager (lazy.nvim): The plugin is managed via lazy.nvim, which is a popular plugin manager for Neovim. This indicates that the plugin is loaded and managed as part of Neovim's plugin ecosystem.
• Event Trigger: The plugin is set to load on the User FilePost event. This means that blink.pairs is initialized after a file is opened. While this approach aims to delay the plugin's activation, it might still interfere with performance if the file is very large.
• Dependencies: blink.pairs has a dependency on saghen/blink.download, which suggests that it relies on another plugin for certain functionalities. This dependency could potentially introduce additional overhead.
• Options (opts): The plugin's options are defined in a separate file, configs.blink_pairs, which contains the specific configuration settings for blink.pairs.

configs.blink_pairs Configuration

The configs.blink_pairs file contains the core configuration for the plugin. Here’s a detailed look at the settings:

--- @module 'blink.pairs'
--- @type blink.pairs.Config
local M = {
  mappings = {
    disabled_filetypes = {
      "snacks_picker_input",
      "vim",
      "bigfile",
    },
  },
  highlights = {
    groups = {
      "BlinkPairsOrange",
      "BlinkPairsPurple",
      "BlinkPairsBlue",
      "BlinkPairsYellow",
      "BlinkPairsViolet",
    },
  },
}

return M

• mappings.disabled_filetypes: This setting is intended to disable blink.pairs for specific filetypes. The configuration includes `