How to Fix Emacs Eglot Errors — LSP Client Not Connecting

In this tutorial, you'll learn about How to Fix Emacs Eglot Errors. We cover key concepts, practical examples, and best practices.

The Problem

Eglot fails to start:

eglot: LSP server is not responding

or:

eglot: Could not find language server for /path/to/file.py

Quick Fix

Step 1: Install a language server

pip install python-lsp-server
npm install -g typescript typescript-language-server
rustup component add rust-analyzer
go install golang.org/x/tools/gopls@latest

Step 2: Verify the language server is in PATH

which pylsp

If not, add the directory to Emacs' exec-path:

(add-to-list 'exec-path "/path/to/language-server/bin")

Step 3: Start Eglot automatically

(use-package eglot
  :ensure t
  :hook ((python-mode . eglot-ensure)
         (rust-mode . eglot-ensure)))

Step 4: Configure Eglot

(use-package eglot
  :ensure t
  :bind (:map eglot-mode-map
              ("C-c d" . eldoc)
              ("C-c r" . eglot-rename))
  :config
  (setq eglot-autoshutdown t))

Step 5: Check Eglot logs

M-x eglot-show-workspace-configuration
M-x eglot-events-buffer

Prevention

• Install language servers before using Eglot.
• Use eglot-ensure in mode hooks for automatic startup.
• Check the Eglot events buffer if something is not working.

Common Mistakes with eglot error

1. Non-exhaustive pattern matches that compile with warnings then crash at runtime
2. Misunderstanding that String is [Char] with poor performance for large text operations
3. Using foldl instead of foldl' causing stack overflow on large lists

These mistakes appear frequently in real-world EMACS code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

FAQ