Crash with ansible language server

[fredericgiquel]

Thanks for this program. It works well for all language servers I tested with lsp-mode, with the exception of ansible.

How to reproduce

1. Be sure that ansible-language-server is installed and in your PATH
2. export LSP_USE_PLISTS=true
3. Launch Emacs with following minimal init.el

;; Initialize package sources
(require 'package)

(setq package-archives '(("gnu" . "https://elpa.gnu.org/packages/")
                         ("nongnu" . "https://elpa.nongnu.org/nongnu/")
                         ("melpa" . "https://melpa.org/packages/")))

(package-initialize)
(unless package-archive-contents
  (package-refresh-contents))

(require 'use-package)
(setq use-package-always-ensure t)

;; Install packages
(use-package lsp-mode
  :config
  (setq lsp-log-io t))

(use-package yaml-mode)

(use-package ansible
  :after lsp-mode yaml-mode
  :hook
  (yaml-mode . ansible)
  (ansible . lsp))

;; Copied from https://github.com/blahgeek/emacs-lsp-booster#configure-lsp-mode
(defun lsp-booster--advice-json-parse (old-fn &rest args)
  "Try to parse bytecode instead of json."
  (or
   (when (equal (following-char) ?#)
     (let ((bytecode (read (current-buffer))))
       (when (byte-code-function-p bytecode)
         (funcall bytecode))))
   (apply old-fn args)))
(advice-add (if (progn (require 'json)
                       (fboundp 'json-parse-buffer))
                'json-parse-buffer
              'json-read)
            :around
            #'lsp-booster--advice-json-parse)

(defun lsp-booster--advice-final-command (old-fn cmd &optional test?)
  "Prepend emacs-lsp-booster command to lsp CMD."
  (let ((orig-result (funcall old-fn cmd test?)))
    (if (and (not test?)                             ;; for check lsp-server-present?
             (not (file-remote-p default-directory)) ;; see lsp-resolve-final-command, it would add extra shell wrapper
             lsp-use-plists
             (not (functionp 'json-rpc-connection))  ;; native json-rpc
             (executable-find "emacs-lsp-booster"))
        (progn
          (message "Using emacs-lsp-booster for %s!" orig-result)
          (cons "emacs-lsp-booster" orig-result))
      orig-result)))
(advice-add 'lsp-resolve-final-command :around #'lsp-booster--advice-final-command)

4. Open a yaml file and, if necessary, import project root in lsp-mode

Logs

*ansible-ls::stderr buffer:

[2024-01-17T21:06:08Z INFO  emacs_lsp_booster::app] Running server "/home/fred/.local/bin/ansible-language-server" "--stdio"
[2024-01-17T21:06:08Z INFO  emacs_lsp_booster::app] Will convert server json to bytecode! bytecode options: BytecodeOptions { object_type: Plist, null_value: Nil, false_value: Nil }
thread '<unnamed>' panicked at /github/workspace/src/app.rs:145:18:
called `Result::unwrap()` on an `Err` value: Server->client read thread failed

Caused by:
    Invalid header format
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Process ansible-ls stderr finished

Last exchange in *lsp-log: ansible-ls* buffer:

[Trace - 10:06:08 ] Received request 'workspace/configuration - (2).
Params: {
  "items": [
    {
      "scopeUri": "file:///home/fred/ansible-test/ansible.yml",
      "section": "ansible"
    }
  ]
}


[Trace - 10:06:08 ] Sending response 'workspace/configuration - (2)'. Processing request took 0ms
Params: {
  "jsonrpc": "2.0",
  "id": 2,
  "result": [
    {
      "ansible": {
        "path": "ansible",
        "useFullyQualifiedCollectionNames": true
      },
      "validation": {
        "enabled": true,
        "lint": {
          "arguments": "",
          "enabled": true,
          "path": "ansible-lint"
        }
      },
      "completion": {
        "provideRedirectModules": true,
        "provideModuleOptionAliases": true
      },
      "executionEnvironment": {
        "containerEngine": "auto",
        "enabled": false,
        "image": "quay.io/ansible/creator-ee:latest",
        "pull": {
          "policy": "missing",
          "arguments": ""
        },
        "containerOptions": "",
        "volumeMounts": []
      },
      "python": {
        "interpreterPath": "",
        "activationScript": ""
      }
    }
  ]
}

[blahgeek]

Thanks for your report.

I can reproduce this issue in my side. Apparently the ansible language server sends unexpected content to stdout so emacs-lsp-booster cannot correctly handle it. Seems to be the same issue as ansible/ansible-language-server#21 According to the discussion, disabling the ansible-lint feature may fix this issue.

I will also try to see if emacs-lsp-booster could be more tolerant to this kind of error

[fredericgiquel]

You're right. The problem comes from ansible language server that writes debug messages to stdout. This has been fixed recently (in ansible/ansible-language-server#604) but there has been no new release since.
I tested with a server built from the last commit and there is no crash anymore.