Error on every cursor movement using eglot with clangd: error in process filter: eglot--hover-info: Buffer is read-only: #<killed buffer>

[jbulow]

I get the following error on every movement of the cursor:

error in process filter: eglot--hover-info: Buffer is read-only: #<killed buffer>
error in process filter: Buffer is read-only: #<killed buffer>
error in process filter: eglot--hover-info: Buffer is read-only: #<killed buffer>
error in process filter: Buffer is read-only: #<killed buffer>

I'm using eglot with clangd:

(use-package eglot
  :ensure t
  :commands (eglot eglot-ensure)
  :hook ((rust-mode . eglot-ensure)
         (c-mode . eglot-ensure)
         (c++-mode . eglot-ensure))
  :config
  (add-to-list 'eglot-server-programs '((c++-mode c-mode) "clangd" "--log=error"
                                        "-j=8"
                                        "--malloc-trim"
                                        "--background-index"
                                        "--clang-tidy"
                                        "--cross-file-rename"
                                        "--completion-style=detailed"
                                        "--pch-storage=memory"
                                        "--header-insertion=never"
                                        "--header-insertion-decorators=0"))

  (add-hook 'c-mode-hook 'eglot-ensure)
  (add-hook 'c++-mode-hook 'eglot-ensure))

(add-hook 'eglot-managed-mode-hook #'eglot-inlay-hints-mode)

Besides the error messages it seems to work fine but the error messages slows down editing a lot and a lot of keystrokes are lost when typing at the same time as the error pops up.

Enabling debug in emacs does not give any more information. No stacktrace is shown.

Any hints on how I can debug this problem?

[joaotavora]

Any hints on how I can debug this problem?

Follow the steps in https://joaotavora.github.io/eglot/#Troubleshooting-Eglot. You can skip step 3. Do not skip steps 5, 6 and especially 7.

[notcancername]

To reproduce:

Install the latest nightly version of Zig.
Install the latest ZLS from master.

Run this code in an emacs -Q -f package-initialize:

(toggle-debug-on-error)
(find-file "/tmp/temp.zig")
(insert "const std = @import(\"std\")\n\npub fn main() void {\n    const a = 1;\n}\n")
(eglot-ensure)
(previous-line)
(previous-line)
(forward-char)
(forward-char)
(forward-char)
(forward-char)
(forward-char)
(forward-char)
(forward-char)
(forward-char)
(forward-char)
(sleep-for 1)
(forward-char)

event log

[internal] Thu Jun 13 11:37:50 2024:
(:message "Running language server: zls")
[client-request] (id:1) Thu Jun 13 11:37:50 2024:
(:jsonrpc "2.0" :id 1 :method "initialize" :params
	  (:processId 204670 :clientInfo
		      (:name "Eglot")
		      :rootPath "/tmp/" :rootUri "file:///tmp" :initializationOptions #s(hash-table size 1 test eql rehash-size 1.5 rehash-threshold 0.8125 data
												    ())
		      :capabilities
		      (:workspace
		       (:applyEdit t :executeCommand
				   (:dynamicRegistration :json-false)
				   :workspaceEdit
				   (:documentChanges t)
				   :didChangeWatchedFiles
				   (:dynamicRegistration t)
				   :symbol
				   (:dynamicRegistration :json-false)
				   :configuration t :workspaceFolders t)
		       :textDocument
		       (:synchronization
			(:dynamicRegistration :json-false :willSave t :willSaveWaitUntil t :didSave t)
			:completion
			(:dynamicRegistration :json-false :completionItem
					      (:snippetSupport t :deprecatedSupport t :resolveSupport
							       (:properties
								["documentation" "details" "additionalTextEdits"])
							       :tagSupport
							       (:valueSet
								[1]))
					      :contextSupport t)
			:hover
			(:dynamicRegistration :json-false :contentFormat
					      ["markdown" "plaintext"])
			:signatureHelp
			(:dynamicRegistration :json-false :signatureInformation
					      (:parameterInformation
					       (:labelOffsetSupport t)
					       :documentationFormat
					       ["markdown" "plaintext"]
					       :activeParameterSupport t))
			:references
			(:dynamicRegistration :json-false)
			:definition
			(:dynamicRegistration :json-false :linkSupport t)
			:declaration
			(:dynamicRegistration :json-false :linkSupport t)
			:implementation
			(:dynamicRegistration :json-false :linkSupport t)
			:typeDefinition
			(:dynamicRegistration :json-false :linkSupport t)
			:documentSymbol
			(:dynamicRegistration :json-false :hierarchicalDocumentSymbolSupport t :symbolKind
					      (:valueSet
					       [1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26]))
			:documentHighlight
			(:dynamicRegistration :json-false)
			:codeAction
			(:dynamicRegistration :json-false :codeActionLiteralSupport
					      (:codeActionKind
					       (:valueSet
						["quickfix" "refactor" "refactor.extract" "refactor.inline" "refactor.rewrite" "source" "source.organizeImports"]))
					      :isPreferredSupport t)
			:formatting
			(:dynamicRegistration :json-false)
			:rangeFormatting
			(:dynamicRegistration :json-false)
			:rename
			(:dynamicRegistration :json-false)
			:inlayHint
			(:dynamicRegistration :json-false)
			:publishDiagnostics
			(:relatedInformation :json-false :codeDescriptionSupport :json-false :tagSupport
					     (:valueSet
					      [1 2])))
		       :window
		       (:workDoneProgress t)
		       :general
		       (:positionEncodings
			["utf-32" "utf-8" "utf-16"])
		       :experimental #s(hash-table size 1 test eql rehash-size 1.5 rehash-threshold 0.8125 data
						   ()))
		      :workspaceFolders
		      [(:uri "file:///tmp" :name "/tmp/")]))
[server-reply] (id:1) Thu Jun 13 11:37:50 2024:
(:jsonrpc "2.0" :id 1 :result
	  (:capabilities
	   (:positionEncoding "utf-8" :textDocumentSync
			      (:openClose t :change 2 :willSave t :willSaveWaitUntil t :save t)
			      :completionProvider
			      (:triggerCharacters
			       ["." ":" "@" "]" "/"]
			       :resolveProvider :json-false :completionItem
			       (:labelDetailsSupport t))
			      :hoverProvider t :signatureHelpProvider
			      (:triggerCharacters
			       ["("]
			       :retriggerCharacters
			       [","])
			      :declarationProvider t :definitionProvider t :typeDefinitionProvider t :implementationProvider :json-false :referencesProvider t :documentHighlightProvider t :documentSymbolProvider t :codeActionProvider t :colorProvider :json-false :workspaceSymbolProvider :json-false :documentFormattingProvider t :documentRangeFormattingProvider :json-false :renameProvider t :foldingRangeProvider t :selectionRangeProvider t :semanticTokensProvider
			      (:legend
			       (:tokenTypes
				["namespace" "type" "class" "enum" "interface" "struct" "typeParameter" "parameter" "variable" "property" "enumMember" "event" "function" "method" "macro" "keyword" "modifier" "comment" "string" "number" "regexp" "operator" "decorator" "errorTag" "builtin" "label" "keywordLiteral" "union" "opaque"]
				:tokenModifiers
				["declaration" "definition" "readonly" "static" "deprecated" "abstract" "async" "modification" "documentation" "defaultLibrary" "generic" "_"])
			       :range t :full t)
			      :inlayHintProvider t :workspace
			      (:workspaceFolders
			       (:supported t :changeNotifications t)))
	   :serverInfo
	   (:name "zls" :version "0.12.0")))
[client-notification] Thu Jun 13 11:37:50 2024:
(:jsonrpc "2.0" :method "initialized" :params #s(hash-table size 1 test eql rehash-size 1.5 rehash-threshold 0.8125 data
							    ()))
[client-notification] Thu Jun 13 11:37:50 2024:
(:jsonrpc "2.0" :method "textDocument/didOpen" :params
	  (:textDocument
	   (:uri "file:///tmp/temp.zig" :version 0 :languageId "zig" :text "const std = @import(\"std\")\n\npub fn main() void {\n    const a = 1;\n}\n")))
[client-notification] Thu Jun 13 11:37:50 2024:
(:jsonrpc "2.0" :method "workspace/didChangeConfiguration" :params
	  (:settings #s(hash-table size 1 test eql rehash-size 1.5 rehash-threshold 0.8125 data
				   ())))
[client-request] (id:2) Thu Jun 13 11:37:50 2024:
(:jsonrpc "2.0" :id 2 :method "textDocument/inlayHint" :params
	  (:textDocument
	   (:uri "file:///tmp/temp.zig")
	   :range
	   (:start
	    (:line 0 :character 0)
	    :end
	    (:line 5 :character 0))))
[server-request] (id:i_haz_configuration) Thu Jun 13 11:37:50 2024:
(:jsonrpc "2.0" :id "i_haz_configuration" :method "workspace/configuration" :params
	  (:items
	   [(:section "zls.enable_snippets")
	    (:section "zls.enable_argument_placeholders")
	    (:section "zls.enable_build_on_save")
	    (:section "zls.build_on_save_step")
	    (:section "zls.enable_autofix")
	    (:section "zls.semantic_tokens")
	    (:section "zls.enable_inlay_hints")
	    (:section "zls.inlay_hints_show_variable_type_hints")
	    (:section "zls.inlay_hints_show_struct_literal_field_type")
	    (:section "zls.inlay_hints_show_parameter_name")
	    (:section "zls.inlay_hints_show_builtin")
	    (:section "zls.inlay_hints_exclude_single_argument")
	    (:section "zls.inlay_hints_hide_redundant_param_names")
	    (:section "zls.inlay_hints_hide_redundant_param_names_last_token")
	    (:section "zls.warn_style")
	    (:section "zls.highlight_global_var_declarations")
	    (:section "zls.dangerous_comptime_experiments_do_not_enable")
	    (:section "zls.skip_std_references")
	    (:section "zls.prefer_ast_check_as_child_process")
	    (:section "zls.builtin_path")
	    (:section "zls.zig_lib_path")
	    (:section "zls.zig_exe_path")
	    (:section "zls.build_runner_path")
	    (:section "zls.global_cache_path")
	    (:section "zls.build_runner_global_cache_path")
	    (:section "zls.completion_label_details")]))
[client-reply] (id:i_haz_configuration) Thu Jun 13 11:37:50 2024:
(:jsonrpc "2.0" :id "i_haz_configuration" :result
	  [nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil])
[server-notification] Thu Jun 13 11:37:50 2024:
(:jsonrpc "2.0" :method "textDocument/publishDiagnostics" :params
	  (:uri "file:///tmp/temp.zig" :diagnostics
		[(:range
		  (:start
		   (:line 0 :character 25)
		   :end
		   (:line 0 :character 26))
		  :severity 1 :code "expected_semi_after_decl" :source "zls" :message "expected ';' after declaration")]))
[server-request] (id:semantic_tokens_refresh) Thu Jun 13 11:37:50 2024:
(:jsonrpc "2.0" :id "semantic_tokens_refresh" :method "workspace/semanticTokens/refresh")
[client-reply] (id:semantic_tokens_refresh) Thu Jun 13 11:37:50 2024:
(:jsonrpc "2.0" :id "semantic_tokens_refresh" :result nil)
[server-reply] (id:2) Thu Jun 13 11:37:50 2024:
(:jsonrpc "2.0" :id 2 :result
	  [(:position
	    (:line 3 :character 11)
	    :label ": comptime_int" :kind 1 :paddingLeft :json-false :paddingRight :json-false)])
[stderr] info : ( main ): Starting ZLS 0.12.0 @ '/usr/local/bin/zls'
[stderr] info : (server): Client is 'Eglot-<no version>'
[stderr] debug: (server): Offset Encoding: utf-8
[stderr] info : (server): Set config option 'enable_autofix' to 'true'
[stderr] info : (server): Set config option 'inlay_hints_show_builtin' to 'false'
[stderr] info : (server): Set config option 'warn_style' to 'true'
[stderr] info : (server): Set config option 'builtin_path' to '/home/user/.cache/zls/builtin.zig'
[stderr] info : (server): Set config option 'zig_lib_path' to '/home/user/Downloads/zig-linux-x86_64-0.12.0/lib'
[stderr] info : (server): Set config option 'zig_exe_path' to '/usr/local/bin/zig-0.12.0'
[stderr] info : (server): Set config option 'build_runner_path' to '/home/user/.cache/zls/build_runner_0.12.0.zig'
[stderr] info : (server): Set config option 'global_cache_path' to '/home/user/.cache/zls'
[stderr] info : (server): Set config option 'build_runner_global_cache_path' to '/home/user/.cache/zig'
[stderr] debug: (server): Took 17ms to process request-1-initialize on Thread 223206
[stderr] debug: (server): Took 0ms to process notification-initialized on Thread 223206
[stderr] debug: (store ): Opened document `file:///tmp/temp.zig`
[stderr] debug: (server): Took 1ms to process notification-textDocument/didOpen on Thread 223206
[stderr] debug: (server): Took 7ms to process notification-workspace/didChangeConfiguration on Thread 223206
[stderr] debug: (server): Took 0ms to process request-2-textDocument/inlayHint on Thread 223208
[server-request] (id:semantic_tokens_refresh) Thu Jun 13 11:37:50 2024:
(:jsonrpc "2.0" :id "semantic_tokens_refresh" :method "workspace/semanticTokens/refresh")
[client-reply] (id:semantic_tokens_refresh) Thu Jun 13 11:37:50 2024:
(:jsonrpc "2.0" :id "semantic_tokens_refresh" :result nil)
[stderr] debug: (server): Took 9ms to process response-i_haz_configuration on Thread 223206
[stderr] debug: (server): Took 0ms to process response-semantic_tokens_refresh on Thread 223206
[stderr] debug: (server): Took 0ms to process response-semantic_tokens_refresh on Thread 223206
[client-request] (id:3) Thu Jun 13 11:38:00 2024:
(:jsonrpc "2.0" :id 3 :method "textDocument/hover" :params
	  (:textDocument
	   (:uri "file:///tmp/temp.zig")
	   :position
	   (:line 3 :character 10)))
[client-request] (id:4) Thu Jun 13 11:38:00 2024:
(:jsonrpc "2.0" :id 4 :method "textDocument/documentHighlight" :params
	  (:textDocument
	   (:uri "file:///tmp/temp.zig")
	   :position
	   (:line 3 :character 10)))
[client-request] (id:5) Thu Jun 13 11:38:00 2024:
(:jsonrpc "2.0" :id 5 :method "textDocument/signatureHelp" :params
	  (:textDocument
	   (:uri "file:///tmp/temp.zig")
	   :position
	   (:line 3 :character 10)))
[server-reply] (id:5) Thu Jun 13 11:38:00 2024:
(:jsonrpc "2.0" :id 5 :result nil)
[stderr] debug: (server): Took 0ms to process request-5-textDocument/signatureHelp on Thread 223207
[server-reply] (id:4) Thu Jun 13 11:38:00 2024:
(:jsonrpc "2.0" :id 4 :result
	  [(:range
	    (:start
	     (:line 3 :character 10)
	     :end
	     (:line 3 :character 11))
	    :kind 1)])
[server-reply] (id:3) Thu Jun 13 11:38:00 2024:
(:jsonrpc "2.0" :id 3 :result
	  (:contents
	   (:kind "markdown" :value "```zig\nconst a = 1\n```\n```zig\n(comptime_int)\n```")
	   :range
	   (:start
	    (:line 3 :character 10)
	    :end
	    (:line 3 :character 11))))
[stderr] debug: (server): Took 2ms to process request-4-textDocument/documentHighlight on Thread 223210
[stderr] debug: (server): Took 3ms to process request-3-textDocument/hover on Thread 223209
[client-notification] Thu Jun 13 11:44:40 2024:
(:jsonrpc "2.0" :method "textDocument/didClose" :params
	  (:textDocument
	   (:uri "file:///tmp/temp.zig")))
[stderr] debug: (store ): Closing document file:///tmp/temp.zig
[stderr] debug: (server): Took 3ms to process notification-textDocument/didClose on Thread 223206
[server-notification] Thu Jun 13 11:44:40 2024:
(:jsonrpc "2.0" :method "textDocument/publishDiagnostics" :params
	  (:uri "file:///tmp/temp.zig" :diagnostics
		[]))
[client-notification] Thu Jun 13 11:45:43 2024:
(:jsonrpc "2.0" :method "textDocument/didOpen" :params
	  (:textDocument
	   (:uri "file:///tmp/temp.zig" :version 0 :languageId "zig" :text "")))
[stderr] debug: (store ): Opened document `file:///tmp/temp.zig`
[stderr] debug: (server): Took 4ms to process notification-textDocument/didOpen on Thread 223206
[server-notification] Thu Jun 13 11:45:43 2024:
(:jsonrpc "2.0" :method "textDocument/publishDiagnostics" :params
	  (:uri "file:///tmp/temp.zig" :diagnostics
		[]))
[internal] (id:6) Thu Jun 13 11:45:45 2024:
(:deferring :textDocument/hover :id 6 :params
	    (:textDocument
	     (:uri "file:///tmp/temp.zig")
	     :position
	     (:line 3 :character 10)))
[internal] (id:7) Thu Jun 13 11:45:45 2024:
(:deferring :textDocument/documentHighlight :id 7 :params
	    (:textDocument
	     (:uri "file:///tmp/temp.zig")
	     :position
	     (:line 3 :character 10)))
[internal] (id:8) Thu Jun 13 11:45:45 2024:
(:deferring :textDocument/signatureHelp :id 8 :params
	    (:textDocument
	     (:uri "file:///tmp/temp.zig")
	     :position
	     (:line 3 :character 10)))
[client-notification] Thu Jun 13 11:45:45 2024:
(:jsonrpc "2.0" :method "textDocument/didChange" :params
	  (:textDocument
	   (:uri "file:///tmp/temp.zig" :version 1)
	   :contentChanges
	   [(:range
	     (:start
	      (:line 0 :character 0)
	      :end
	      (:line 0 :character 0))
	     :rangeLength 0 :text "const std = @import(\"std\")\n\npub fn main() void {\n    const a = 1;\n}\n")]))
[internal] Thu Jun 13 11:45:45 2024:
(:maybe-run-deferred
 (8 7 6))
[client-request] (id:8) Thu Jun 13 11:45:45 2024:
(:jsonrpc "2.0" :id 8 :method "textDocument/signatureHelp" :params
	  (:textDocument
	   (:uri "file:///tmp/temp.zig")
	   :position
	   (:line 3 :character 10)))
[client-request] (id:7) Thu Jun 13 11:45:45 2024:
(:jsonrpc "2.0" :id 7 :method "textDocument/documentHighlight" :params
	  (:textDocument
	   (:uri "file:///tmp/temp.zig")
	   :position
	   (:line 3 :character 10)))
[client-request] (id:6) Thu Jun 13 11:45:45 2024:
(:jsonrpc "2.0" :id 6 :method "textDocument/hover" :params
	  (:textDocument
	   (:uri "file:///tmp/temp.zig")
	   :position
	   (:line 3 :character 10)))
[stderr] debug: (server): Took 5ms to process notification-textDocument/didChange on Thread 223206
[server-notification] Thu Jun 13 11:45:45 2024:
(:jsonrpc "2.0" :method "textDocument/publishDiagnostics" :params
	  (:uri "file:///tmp/temp.zig" :diagnostics
		[(:range
		  (:start
		   (:line 0 :character 25)
		   :end
		   (:line 0 :character 26))
		  :severity 1 :code "expected_semi_after_decl" :source "zls" :message "expected ';' after declaration")]))
[server-reply] (id:8) Thu Jun 13 11:45:45 2024:
(:jsonrpc "2.0" :id 8 :result nil)
[stderr] debug: (server): Took 3ms to process request-8-textDocument/signatureHelp on Thread 223210
[stderr] debug: (server): Took 6ms to process request-7-textDocument/documentHighlight on Thread 223209
[stderr] debug: (server): Took 3ms to process request-6-textDocument/hover on Thread 223208
[server-reply] (id:7) Thu Jun 13 11:45:45 2024:
(:jsonrpc "2.0" :id 7 :result
	  [(:range
	    (:start
	     (:line 3 :character 10)
	     :end
	     (:line 3 :character 11))
	    :kind 1)])
[server-reply] (id:6) Thu Jun 13 11:45:45 2024:
(:jsonrpc "2.0" :id 6 :result
	  (:contents
	   (:kind "markdown" :value "```zig\nconst a = 1\n```\n```zig\n(comptime_int)\n```")
	   :range
	   (:start
	    (:line 3 :character 10)
	    :end
	    (:line 3 :character 11))))
[internal] (id:6) Thu Jun 13 11:45:55 2024:
(:timed-out :textDocument/hover :id 6 :params
	    (:textDocument
	     (:uri "file:///tmp/temp.zig")
	     :position
	     (:line 3 :character 10)))
[internal] (id:7) Thu Jun 13 11:45:55 2024:
(:timed-out :textDocument/documentHighlight :id 7 :params
	    (:textDocument
	     (:uri "file:///tmp/temp.zig")
	     :position
	     (:line 3 :character 10)))
[internal] (id:8) Thu Jun 13 11:45:55 2024:
(:timed-out :textDocument/signatureHelp :id 8 :params
	    (:textDocument
	     (:uri "file:///tmp/temp.zig")
	     :position
	     (:line 3 :character 10)))

Emacs version: GNU Emacs 29.3 (build 2, x86_64-pc-linux-gnu, GTK+ Version 3.24.38, cairo version 1.16.0) of 2024-06-13

No backtrace because toggle-debug-on-error didn't provide one.

[joaotavora]

You used package-initialize but there is no mention of what packages are needed. I assume something zig-mode and only that.

Also, can you do an interactive, non-Elisp version of this recipe? Where you actually type M-x toggle.... interactive and non-interactive versions of function behave differently and Eglot is for interactive use. Just say exactly what a non-Elisper Emacs user and Zig hello-worlder would do that would bring them to the supposed exact same error error of the C++ cland user. Male sure it works reliably, if it doesn't please mention that. Thanks.