textDocument/completion payload sizes can be very large because of documentation of in-scope items

[onism0106]

When using the textDocument/completion method for code completion, a large amount of irrelevant information is returned, including the documentation field. How can I solve this issue? The editor is a custom code editor implemented with Flutter. I have set "suggestFromUnimportedLibraries": false during initialization, but it has not had any effect.

[bwilkerson]

Are you setting the resolveSupport client configuration data to indicate that these fields can be returned later? More generally, please let us know what client configuration data you're sending to the server.

@DanTup

[DanTup]

Currently, resolve is only used for completion items that are not already imported. For all things currently in-scope, the documentation (and other fields) are included inline. This is one of the things noted at #53501 (I believe there was something that made it non-trivial, but I don't recall the specifics right now).

You can control the level of documentation that is included (here and in hovers) with the dart.documentation configuration setting and you can also reduce the number of items included with the "dart.maxCompletionItems" setting.

[onism0106]

resolveSupport

yes, I have set the resolveSupport. My capabilities are as follows:

But it still return the documentation field, which is a very large content

Map<String, dynamic> clientCapabilities = {
  "workspace": {
    "applyEdit": true,
    "workspaceEdit": {
      "documentChanges": true,
      "resourceOperations": ["create", "rename", "delete"],
      "failureHandling": "textOnlyTransactional",
      "normalizesLineEndings": true,
      "changeAnnotationSupport": {"groupsOnLabel": true}
    },
    "configuration": true,
    "didChangeWatchedFiles": {
      "dynamicRegistration": true,
      "relativePatternSupport": 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]
      },
      "resolveSupport": {
        "properties": ["location.range"]
      }
    },
    "codeLens": {"refreshSupport": true},
    "executeCommand": {"dynamicRegistration": true},
    "didChangeConfiguration": {"dynamicRegistration": true},
    "workspaceFolders": true,
    "semanticTokens": {"refreshSupport": true},
    "fileOperations": {
      "dynamicRegistration": true,
      "didCreate": true,
      "didRename": true,
      "didDelete": true,
      "willCreate": true,
      "willRename": true,
      "willDelete": true
    },
    "inlineValue": {"refreshSupport": true},
    "inlayHint": {"refreshSupport": true},
    "diagnostics": {"refreshSupport": 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]
        },
        "labelDetailsSupport": true
      },
      "insertTextMode": 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
        ]
      },
      "completionList": {
        "itemDefaults": [
          "commitCharacters",
          "editRange",
          "insertTextFormat",
          "insertTextMode"
        ]
      }
    },
    "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,
      "foldingRangeKind": {
        "valueSet": ["comment", "imports", "region"]
      },
      "foldingRange": {"collapsedText": false}
    },
    "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",
        "decorator"
      ],
      "tokenModifiers": [
        "declaration",
        "definition",
        "readonly",
        "static",
        "deprecated",
        "abstract",
        "async",
        "modification",
        "documentation",
        "defaultLibrary"
      ],
      "formats": ["relative"],
      "requests": {
        "range": true,
        "full": {"delta": true}
      },
      "multilineTokenSupport": false,
      "overlappingTokenSupport": false,
      "serverCancelSupport": true,
      "augmentsSyntaxTokens": true
    },
    "linkedEditingRange": {"dynamicRegistration": true},
    "typeHierarchy": {"dynamicRegistration": true},
    "inlineValue": {"dynamicRegistration": true},
    "inlayHint": {
      "dynamicRegistration": true,
      "resolveSupport": {
        "properties": [
          "tooltip",
          "textEdits",
          "label.tooltip",
          "label.location",
          "label.command"
        ]
      }
    },
    "diagnostic": {"dynamicRegistration": true, "relatedDocumentSupport": false}
  },
  "window": {
    "showMessage": {
      "messageActionItem": {"additionalPropertiesSupport": true}
    },
    "showDocument": {"support": true},
    "workDoneProgress": true
  },
  "general": {
    "staleRequestSupport": {
      "cancel": true,
      "retryOnContentModified": [
        "textDocument/semanticTokens/full",
        "textDocument/semanticTokens/range",
        "textDocument/semanticTokens/full/delta"
      ]
    },
    "regularExpressions": {"engine": "ECMAScript", "version": "ES2020"},
    "markdown": {
      "parser": "marked",
      "version": "1.1.0",
      "allowedTags": [
        "ul",
        "li",
        "p",
        "code",
        "blockquote",
        "ol",
        "h1",
        "h2",
        "h3",
        "h4",
        "h5",
        "h6",
        "hr",
        "em",
        "pre",
        "table",
        "thead",
        "tbody",
        "tr",
        "th",
        "td",
        "div",
        "del",
        "a",
        "strong",
        "br",
        "img",
        "span"
      ]
    },
    "positionEncodings": ["utf-16"]
  },
  "notebookDocument": {
    "synchronization": {
      "dynamicRegistration": true,
      "executionSummarySupport": true
    }
  },
  "experimental": {
    "supportsWindowShowMessageRequest": true,
    "snippetTextEdit": true,
    "dartCodeAction": {
      "commandParameterSupport": {
        "supportedKinds": ["saveUri"]
      }
    }
  }
};

[DanTup]

@onism0106 have you tried changing the dart.documentation (or dart.maxCompletionItems) settings noted above?

For now, I think those are the only options that will help here, until we support resolve for the already-in-scope items.

Out of interest - what problem is the payload size causing you? (memory usage? time taken to deserialize json? time to send bytes between server and client?). Is your editor open source?

[DanTup]

I started looking at why we didn't use /resolve for documentation generally and added some notes in #53501 (comment). It was mostly that I was hoping that microsoft/language-server-protocol#1802 would be implemented which would avoid us having to add so much to the payload in order to use /resolve here.

[onism0106]

@onism0106 have you tried changing the dart.documentation (or dart.maxCompletionItems) settings noted above?

For now, I think those are the only options that will help here, until we support resolve for the already-in-scope items.

Out of interest - what problem is the payload size causing you? (memory usage? time taken to deserialize json? time to send bytes between server and client?). Is your editor open source?

Yes, I am worried about performance issues because there will be frequent interactions with the LSP, each time returning a large amount of data. I am concerned that this might cause performance problems，(memory usage? time taken to deserialize json).

I don't know if my concern is unnecessary.

I'll try set dart.documentation (or dart.maxCompletionItems) later

[DanTup]

If it helps, the payload sizes you're seeing here match what VS Code is dealing with today. I can't be sure the equivalent Dart code performs the same as VS Code's javascript, but hopefully it won't cause any real performance issues.

However, I have pinged on the LSP issue about this, and depending on the response (or lack of), may try to progress something in this area (because there is value in reducing payload sizes for some other situations, like when the extension host/LSP server is on a remote machine).