Python LSP server completely stops working after a cancel notification is received

[hugorichard]

I installed pylsp and all required modules.
When using python-lsp-server I see the following warning
"2021-11-14 15:12:47,855 CET - WARNING - pylsp_jsonrpc.endpoint - Received cancel notification for unknown message id 10"
and then everything stops working : the auto-completions, linting, signature help.

I am a spacemacs user (=emacs). A lot of other users (including some people using different IDE) have experienced this issue. See:
palantir/python-jsonrpc-server#17
python-lsp/python-lsp-jsonrpc#5
emacs-lsp/lsp-mode#1731
palantir/python-jsonrpc-server#17

Any ideas on what could be the problem ?

Best,
Hugo

[m0wer]

Same here from using nvim 0.6.1 with the following config:

nvim_lsp.pylsp.setup(require('coq').lsp_ensure_capabilities({
    settings = {
        pylsp = {
            configurationSources = {'flake8', 'pycodestyle'},
            plugins = {
                jedi_completion = {
                    fuzzy = true,
                },
                flake8 = {
                    enabled = true,
                    config = ".flake8",
                },
                pycodestyle = {
                    enabled = true,
                },
                mccabe = {
                    enabled = true,
                },
                preload = {
                    enabled = false,
                },
                pydocstyle = {
                    enabled = true,
                },
                pylint = {
                    enabled = false,
                },
                pyflakes = {
                    enabled = false,
                },
                rope_completion = {
                    enabled = true,
                },
                yapf = {
                    enabled = false,
                },
            },
        },
    },
    flags = {
      debounce_text_changes = 150,
    },
  }))

The process pylsp uses 100% of CPU and logs (~/.cache/nvim/lsp.log) show something like this:

[ERROR][2022-06-14 10:55:40] .../vim/lsp/rpc.lua:420	"rpc"	"pylsp"	"stderr"	"2022-06-14 10:55:40,342 +03 - WARNING - pylsp_jsonrpc.endpoint - Received cancel notification for unknown message id 129\n"
[ERROR][2022-06-14 10:55:46] .../vim/lsp/rpc.lua:420	"rpc"	"pylsp"	"stderr"	"2022-06-14 10:55:46,355 +03 - WARNING - pylsp_jsonrpc.endpoint - Received cancel notification for unknown message id 130\n"
[ERROR][2022-06-14 10:55:50] .../vim/lsp/rpc.lua:420	"rpc"	"pylsp"	"stderr"	"2022-06-14 10:55:50,056 +03 - WARNING - pylsp_jsonrpc.endpoint - Received cancel notification for unknown message id 131\n"
[ERROR][2022-06-14 10:55:53] .../vim/lsp/rpc.lua:420	"rpc"	"pylsp"	"stderr"	"2022-06-14 10:55:53,421 +03 - WARNING - pylsp_jsonrpc.endpoint - Received cancel notification for unknown message id 132\n"

[ccordoba12]

@m0wer, please describe step by step how to set up a Neovim instance with LSP and this server working. That way I could reproduce this error on my side and then try to fix it.

[Noborita9]

Hi, I started having this problem yesterday,
I updated my plugins with PackerSync and the python-language-server started being slow, in just around 20s it stops sending suggestions, it just gives syntax errors and its super slow. If any more information is needed i would like to contribute to solve this

[satyajeet-sundial]

@ccordoba12 this is quite easily reproducible in emacs with lsp-mode with quite a minimal setup

[satyajeet-sundial]

This is what the sample log lines in my log looks like:

2023-05-17 11:17:33,077 IST - WARNING - pylsp_jsonrpc.endpoint - Received cancel notification for unknown message id 4073
2023-05-17 11:17:33,106 IST - WARNING - pylsp_jsonrpc.endpoint - Received cancel notification for unknown message id 4074
2023-05-17 11:17:34,681 IST - WARNING - pylsp_jsonrpc.endpoint - Received cancel notification for unknown message id 4072
2023-05-17 11:17:34,698 IST - WARNING - pylsp_jsonrpc.endpoint - Received cancel notification for unknown message id 4078

[carlos-gtz]

I'm having the same issue with neovim nvim-lspconfig. All those "WARNING - pylsp_jsonrpc.endpoint" messages are being spammed on lsp log

My configuration is:

{
   settings = {
      pylsp = {
         plugins = {
            configurationSources = { "flake8" },

            autopep8 = { enabled = false },
            flake8 = { enabled = true },
            mccabe = { enabled = false },
            preload = { enabled = false },
            pycodestyle = { enabled = false },
            pydocstyle = { enabled = false },
            pyflakes = { enabled = false },
            pylint = { enabled = false },
            yapf = { enabled = false },

            -- https://github.com/python-rope/pylsp-rope
            rope_auto_import = { enabled = false, memory = false },
            rope_completion = { enabled = false, eager = false },

            -- 3rd party plugins
            -- https://github.com/Richardk2n/pylsp-mypy
            pylsp_mypy = {
               live_mode = false,
               report_progress = true,
               dmypy = true,
            },

            isort = { enabled = true },
            black = { enabled = true, cache_config = true },
            ruff = { enabled = true },

            -- Jedi configuration
            jedi_hover = { enabled = true },
            jedi_signature_help = { enabled = true },
            jedi_references = { enabled = true },
            jedi_symbols = { enabled = true },
            jedi_definition = {
               enabled = true,
               follow_imports = true,
               follow_builtin_imports = true,
               follow_builtin_definitions = true,
            },
            jedi_completion = {
               enabled = true,
               include_params = true,
               include_class_objects = false,
               include_function_objects = false,
               fuzzy = false,
               eager = false,
               resolve_at_most = 25,
               cache_for = {
                  "pandas",
                  "numpy",
                  "tensorflow",
                  "matplotlib",
                  "pydantic",
                  "fastapi",
                  "flask",
                  "sqlalchemy",
                  "dagster",
               },
            },
         },
      },
   },
}

[malashinroman]

same issue with neovim 0.8.3 or 0.9.1

[fecet]

same issue with neovim nightly

[ccordoba12]

We'll see what we can do about this problem in our next version.