JETLS: `DataFrame` is not defined

New to Julia
,
1

How can I avoid these kinds of errors? My understanding is that JETLS is not starting in my current environment. How can I make it start? Or should I add DataFrames to the main Julia environment?

2

More context helps others understand your problem. Please see below.

3

I use eglot in emacs with JETLS. My main julia environment does not have DataFrames. I make separate packages for each project and install DataFrames separately in each project. My config details below. For JETLS install, I’m using the documentation.

Emacs init and Julia pkg details 
;; Julia REPL
(use-package julia-repl
  :ensure t
  :hook (julia-ts-mode . julia-repl-mode)
  :config
  (julia-repl-set-terminal-backend 'vterm)
  (setq julia-repl-executable-records '((default "julia" :basedir "/Users/foo/applications/julia/usr/share/julia/base/")))
  (setq julia-repl-executable-key 'default)
)

;;
;; Eglot
;;
(use-package sideline-eglot
  :ensure t
  :init
  (setq sideline-backends-right '(sideline-eglot)))

;; Set up the Language Server Protocol (LSP) servers using Eglot.
(use-package eglot
  :ensure t
  :hook ((eglot-mode . sideline-mode)
         (ess-r-mode . eglot-ensure))
  :commands (eglot-ensure
             eglot-rename
             eglot-format-buffer))

(with-eval-after-load 'eglot
  (add-to-list 'eglot-server-programs
               '(((julia-mode :language-id "julia")
                  (julia-ts-mode :language-id "julia"))
                 "jetls"
                 "--threads=auto"
                 "--"
                 "serve"
                 "--socket"
                 :autoport))
  (add-to-list 'eglot-server-programs
               '(ess-r-mode . ("R" "--slave" "--args" "-e" "languageserver::run()"))))

(use-package consult-eglot
  :ensure t)

(use-package consult-eglot-embark
  :ensure t)

(with-eval-after-load 'embark
  (with-eval-after-load 'consult-eglot
    (require 'consult-eglot-embark)
    (consult-eglot-embark-mode)))


(@v1.13) pkg> st
Status `~/.julia/environments/v1.13/Project.toml`
  [2b0e0bc5] LanguageServer v6.0.1
  [295af30f] Revise v3.17.2

(@v1.13) pkg> app status
[a3b70258] JETLS v2026.10.4 `https://github.com/aviatesk/JETLS.jl#release`
  jetls ~/applications/julia/usr/bin/julia
[62bfec6d] Runic v1.13.0
  git-runic ~/applications/julia/usr/bin/julia
  runic ~/applications/julia/usr/bin/julia