racket-langserver

racket-langserver copied to clipboard

I am not entirely sure this problem really exists, but I have found that the response for textDocument/completion seems to give a wrong Content-Length. However, using racket-langserver with VSCode is all right, but I'm not sure whether VSCode uses the Content-Length field or just reads a complete JSON object for parsing responses.

The way to reproduce the issue:

• Operating system: macOS 12.2.1
• Racket: v8.3 [cs]
• Put the following text into a file requests.txt (contains 4 requests: initialize, didOpen, didChange (inserts a character), completion (requests completion) ). Use CRLF.

Content-Length: 0

{"jsonrpc":"2.0","id":0,"method":"initialize","params":{"processId":7404,"clientInfo":{"name":"Visual Studio Code","version":"1.64.2"},"locale":"en-us","rootPath":"/","rootUri":"file:///","capabilities":{"workspace":{"applyEdit":true,"workspaceEdit":{"documentChanges":true,"resourceOperations":["create","rename","delete"],"failureHandling":"textOnlyTransactional","normalizesLineEndings":true,"changeAnnotationSupport":{"groupsOnLabel":true}},"didChangeConfiguration":{"dynamicRegistration":true},"didChangeWatchedFiles":{"dynamicRegistration":true},"symbol":{"dynamicRegistration":true,"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]},"tagSupport":{"valueSet":[1]}},"codeLens":{"refreshSupport":true},"executeCommand":{"dynamicRegistration":true},"configuration":true,"workspaceFolders":true,"semanticTokens":{"refreshSupport":true},"fileOperations":{"dynamicRegistration":true,"didCreate":true,"didRename":true,"didDelete":true,"willCreate":true,"willRename":true,"willDelete":true}},"textDocument":{"publishDiagnostics":{"relatedInformation":true,"versionSupport":false,"tagSupport":{"valueSet":[1,2]},"codeDescriptionSupport":true,"dataSupport":true},"synchronization":{"dynamicRegistration":true,"willSave":true,"willSaveWaitUntil":true,"didSave":true},"completion":{"dynamicRegistration":true,"contextSupport":true,"completionItem":{"snippetSupport":true,"commitCharactersSupport":true,"documentationFormat":["markdown","plaintext"],"deprecatedSupport":true,"preselectSupport":true,"tagSupport":{"valueSet":[1]},"insertReplaceSupport":true,"resolveSupport":{"properties":["documentation","detail","additionalTextEdits"]},"insertTextModeSupport":{"valueSet":[1,2]}},"completionItemKind":{"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]}},"hover":{"dynamicRegistration":true,"contentFormat":["markdown","plaintext"]},"signatureHelp":{"dynamicRegistration":true,"signatureInformation":{"documentationFormat":["markdown","plaintext"],"parameterInformation":{"labelOffsetSupport":true},"activeParameterSupport":true},"contextSupport":true},"definition":{"dynamicRegistration":true,"linkSupport":true},"references":{"dynamicRegistration":true},"documentHighlight":{"dynamicRegistration":true},"documentSymbol":{"dynamicRegistration":true,"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]},"hierarchicalDocumentSymbolSupport":true,"tagSupport":{"valueSet":[1]},"labelSupport":true},"codeAction":{"dynamicRegistration":true,"isPreferredSupport":true,"disabledSupport":true,"dataSupport":true,"resolveSupport":{"properties":["edit"]},"codeActionLiteralSupport":{"codeActionKind":{"valueSet":["","quickfix","refactor","refactor.extract","refactor.inline","refactor.rewrite","source","source.organizeImports"]}},"honorsChangeAnnotations":false},"codeLens":{"dynamicRegistration":true},"formatting":{"dynamicRegistration":true},"rangeFormatting":{"dynamicRegistration":true},"onTypeFormatting":{"dynamicRegistration":true},"rename":{"dynamicRegistration":true,"prepareSupport":true,"prepareSupportDefaultBehavior":1,"honorsChangeAnnotations":true},"documentLink":{"dynamicRegistration":true,"tooltipSupport":true},"typeDefinition":{"dynamicRegistration":true,"linkSupport":true},"implementation":{"dynamicRegistration":true,"linkSupport":true},"colorProvider":{"dynamicRegistration":true},"foldingRange":{"dynamicRegistration":true,"rangeLimit":5000,"lineFoldingOnly":true},"declaration":{"dynamicRegistration":true,"linkSupport":true},"selectionRange":{"dynamicRegistration":true},"callHierarchy":{"dynamicRegistration":true},"semanticTokens":{"dynamicRegistration":true,"tokenTypes":["namespace","type","class","enum","interface","struct","typeParameter","parameter","variable","property","enumMember","event","function","method","macro","keyword","modifier","comment","string","number","regexp","operator"],"tokenModifiers":["declaration","definition","readonly","static","deprecated","abstract","async","modification","documentation","defaultLibrary"],"formats":["relative"],"requests":{"range":true,"full":{"delta":true}},"multilineTokenSupport":false,"overlappingTokenSupport":false},"linkedEditingRange":{"dynamicRegistration":true}},"window":{"showMessage":{"messageActionItem":{"additionalPropertiesSupport":true}},"showDocument":{"support":true},"workDoneProgress":true},"general":{"regularExpressions":{"engine":"ECMAScript","version":"ES2020"},"markdown":{"parser":"marked","version":"1.1.0"}}},"trace":"off","workspaceFolders":[{"uri":"file:///","name":"Demo"}]}
}Content-Length: 0

{"jsonrpc":"2.0","method":"textDocument/didOpen","params":{"textDocument":{"uri":"file:///a",
"text":"#lang racket\n\n(define i 0)\n(display )\n"}}
}Content-Length: 0

{"jsonrpc":"2.0","method":"textDocument/didChange","params":{
    "textDocument": {
        "uri": "file:///a"
    },
    "contentChanges": [
        {
            "range": {
                "start": {
                    "line": 3,
                    "character": 9
                },
                "end": {
                    "line": 3,
                    "character": 9
                }
            },
            "rangeLength": 0,
            "text": "i"
        }
    ]
}}Content-Length: 0

{"jsonrpc":"2.0","id":2,"method":"textDocument/completion","params":{"textDocument":{"uri":"file:///a"},
"position":{"line":3,"character":10},"context":{"triggerKind":1}}
}

• Run command (cat requests.txt && cat) | racket -l racket-langserver. Wait for enough time that all four requests are processed, then Ctrl-C to terminate.

It's the fourth request that gives the wrong Content-Length (72071), but the actual length of the JSON object is 72066. I've looked into msg-io.rkt, where Content-Length is computed, but I cannot figure out what's going wrong in the code.

To save someone's time, this is in msg-io.rkt

(define (display-message msg [out (current-output-port)])
  (when (verbose-io?)
    (eprintf "\nresp = ~v\n" msg))
  (define null-port (open-output-nowhere))
  (write-json msg null-port)
  (define content-length (file-position null-port))
  (fprintf out "Content-Length: ~a\r\n\r\n" content-length)
  (write-json msg out))

Idea is writing message to nowhere port then rely on file-position as content-length.

The following simple test shows write a string works normally

(define out (open-output-nowhere))
(fprintf out "123")
(file-position out) ; 3

@dannypsnl Thank you for pointing it out! Just out of curiosity, were you able to replicate the issue?

Yes, I have meet this problem before, and it became more frequently in 8.4

I have figured out the problem, and it's my fault. The Content-Length field should be the length of the body in bytes, instead of Unicode characters. I was counting the number of Unicode characters in the response.

But it still shouldn't be 0?

Yes. But it's not 0. The 0s in my original post are in the input, not output from the language server. racket-langserver disregards the Content-Length of input and reads a complete JSON object instead, so using 0 is safe here.

@Dev-XYS Should this issue be closed? It sounds like you worked out what was happening…?

Yes. I will close it now.