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Merged
jakebailey merged 3 commits into from
Nov 3, 2025
Merged

Add docs to signature help #2009

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0fe598f
Add docs to signature help
jakebailey Nov 3, 2025
8071860
Fix doc
jakebailey Nov 3, 2025
96d62ce
Update internal/lsp/server.go
jakebailey Nov 3, 2025
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12 changes: 12 additions & 0 deletions internal/fourslash/fourslash.go
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Original file line number Diff line number Diff line change
Expand Up @@ -297,6 +297,18 @@ func getCapabilitiesWithDefaults(capabilities *lsproto.ClientCapabilities) *lspr
if capabilitiesWithDefaults.TextDocument.Hover == nil {
capabilitiesWithDefaults.TextDocument.Hover = defaultHoverCapabilities
}
if capabilitiesWithDefaults.TextDocument.SignatureHelp == nil {
capabilitiesWithDefaults.TextDocument.SignatureHelp = &lsproto.SignatureHelpClientCapabilities{
SignatureInformation: &lsproto.ClientSignatureInformationOptions{
DocumentationFormat: &[]lsproto.MarkupKind{lsproto.MarkupKindMarkdown, lsproto.MarkupKindPlainText},
ParameterInformation: &lsproto.ClientSignatureParameterInformationOptions{
LabelOffsetSupport: ptrTrue,
},
ActiveParameterSupport: ptrTrue,
},
ContextSupport: ptrTrue,
Comment on lines +304 to +309
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@jakebailey jakebailey Nov 3, 2025 •
edited
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We are not actually checking these correctly currently (different PR).

}
}
return &capabilitiesWithDefaults
}

Expand Down
40 changes: 33 additions & 7 deletions internal/ls/signaturehelp.go
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Original file line number Diff line number Diff line change
Expand Up @@ -44,6 +44,7 @@ func (l *LanguageService) ProvideSignatureHelp(
position lsproto.Position,
context *lsproto.SignatureHelpContext,
clientOptions *lsproto.SignatureHelpClientCapabilities,
docFormat lsproto.MarkupKind,
) (lsproto.SignatureHelpResponse, error) {
program, sourceFile := l.getProgramAndFile(documentURI)
items := l.GetSignatureHelpItems(
Expand All @@ -52,7 +53,8 @@ func (l *LanguageService) ProvideSignatureHelp(
program,
sourceFile,
context,
clientOptions)
clientOptions,
docFormat)
return lsproto.SignatureHelpOrNull{SignatureHelp: items}, nil
}

Expand All @@ -63,6 +65,7 @@ func (l *LanguageService) GetSignatureHelpItems(
sourceFile *ast.SourceFile,
context *lsproto.SignatureHelpContext,
clientOptions *lsproto.SignatureHelpClientCapabilities,
docFormat lsproto.MarkupKind,
) *lsproto.SignatureHelp {
typeChecker, done := program.GetTypeCheckerForFile(ctx, sourceFile)
defer done()
Expand Down Expand Up @@ -140,7 +143,7 @@ func (l *LanguageService) GetSignatureHelpItems(

// return typeChecker.runWithCancellationToken(cancellationToken, typeChecker =>
if candidateInfo.candidateInfo != nil {
return createSignatureHelpItems(candidateInfo.candidateInfo.candidates, candidateInfo.candidateInfo.resolvedSignature, argumentInfo, sourceFile, typeChecker, onlyUseSyntacticOwners, clientOptions)
return l.createSignatureHelpItems(candidateInfo.candidateInfo.candidates, candidateInfo.candidateInfo.resolvedSignature, argumentInfo, sourceFile, typeChecker, onlyUseSyntacticOwners, clientOptions, docFormat)
}
return createTypeHelpItems(candidateInfo.typeInfo, argumentInfo, sourceFile, clientOptions, typeChecker)
}
Expand Down Expand Up @@ -202,7 +205,7 @@ func getTypeHelpItem(symbol *ast.Symbol, typeParameter []*checker.Type, enclosin
}
}

func createSignatureHelpItems(candidates []*checker.Signature, resolvedSignature *checker.Signature, argumentInfo *argumentListInfo, sourceFile *ast.SourceFile, c *checker.Checker, useFullPrefix bool, clientOptions *lsproto.SignatureHelpClientCapabilities) *lsproto.SignatureHelp {
func (l *LanguageService) createSignatureHelpItems(candidates []*checker.Signature, resolvedSignature *checker.Signature, argumentInfo *argumentListInfo, sourceFile *ast.SourceFile, c *checker.Checker, useFullPrefix bool, clientOptions *lsproto.SignatureHelpClientCapabilities, docFormat lsproto.MarkupKind) *lsproto.SignatureHelp {
enclosingDeclaration := getEnclosingDeclarationFromInvocation(argumentInfo.invocation)
if enclosingDeclaration == nil {
return nil
Expand All @@ -223,7 +226,7 @@ func createSignatureHelpItems(candidates []*checker.Signature, resolvedSignature
}
items := make([][]signatureInformation, len(candidates))
for i, candidateSignature := range candidates {
items[i] = getSignatureHelpItem(candidateSignature, argumentInfo.isTypeParameterList, callTargetDisplayParts.String(), enclosingDeclaration, sourceFile, c)
items[i] = l.getSignatureHelpItem(candidateSignature, argumentInfo.isTypeParameterList, callTargetDisplayParts.String(), enclosingDeclaration, sourceFile, c, docFormat)
}

selectedItemIndex := 0
Expand Down Expand Up @@ -262,9 +265,18 @@ func createSignatureHelpItems(candidates []*checker.Signature, resolvedSignature
for j, param := range item.Parameters {
parameters[j] = param.parameterInfo
}
var documentation *lsproto.StringOrMarkupContent
if item.Documentation != nil {
documentation = &lsproto.StringOrMarkupContent{
MarkupContent: &lsproto.MarkupContent{
Kind: docFormat,
Value: *item.Documentation,
},
}
}
signatureInformation[i] = &lsproto.SignatureInformation{
Label: item.Label,
Documentation: nil,
Documentation: documentation,
Parameters: &parameters,
}
}
Expand All @@ -291,7 +303,7 @@ func createSignatureHelpItems(candidates []*checker.Signature, resolvedSignature
return help
}

func getSignatureHelpItem(candidate *checker.Signature, isTypeParameterList bool, callTargetSymbol string, enclosingDeclaration *ast.Node, sourceFile *ast.SourceFile, c *checker.Checker) []signatureInformation {
func (l *LanguageService) getSignatureHelpItem(candidate *checker.Signature, isTypeParameterList bool, callTargetSymbol string, enclosingDeclaration *ast.Node, sourceFile *ast.SourceFile, c *checker.Checker, docFormat lsproto.MarkupKind) []signatureInformation {
var infos []*signatureHelpItemInfo
if isTypeParameterList {
infos = itemInfoForTypeParameters(candidate, c, enclosingDeclaration, sourceFile)
Expand All @@ -301,6 +313,20 @@ func getSignatureHelpItem(candidate *checker.Signature, isTypeParameterList bool

suffixDisplayParts := returnTypeToDisplayParts(candidate, c)

// Generate documentation from the signature's declaration
var documentation *string
if declaration := candidate.Declaration(); declaration != nil {
if jsdoc := getJSDocOrTag(declaration); jsdoc != nil {
isMarkdown := docFormat == lsproto.MarkupKindMarkdown
var b strings.Builder
l.writeComments(&b, c, jsdoc.Comments(), isMarkdown)
if b.Len() > 0 {
docString := b.String()
documentation = &docString
}
}
}

result := make([]signatureInformation, len(infos))
for i, info := range infos {
var display strings.Builder
Expand All @@ -309,7 +335,7 @@ func getSignatureHelpItem(candidate *checker.Signature, isTypeParameterList bool
display.WriteString(suffixDisplayParts)
result[i] = signatureInformation{
Label: display.String(),
Documentation: nil,
Documentation: documentation,
Parameters: info.parameters,
IsVariadic: info.isVariadic,
}
Expand Down
16 changes: 16 additions & 0 deletions internal/lsp/server.go
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Original file line number Diff line number Diff line change
Expand Up @@ -818,6 +818,7 @@ func (s *Server) handleSignatureHelp(ctx context.Context, languageService *ls.La
params.Position,
params.Context,
s.initializeParams.Capabilities.TextDocument.SignatureHelp,
getSignatureHelpDocumentationFormat(s.initializeParams),
)
}

Expand Down Expand Up @@ -1021,3 +1022,18 @@ func getHoverContentFormat(params *lsproto.InitializeParams) lsproto.MarkupKind
// Return the first (most preferred) format
return formats[0]
}

func getSignatureHelpDocumentationFormat(params *lsproto.InitializeParams) lsproto.MarkupKind {
if params == nil || params.Capabilities.TextDocument == nil || params.Capabilities.TextDocument.SignatureHelp == nil ||
params.Capabilities.TextDocument.SignatureHelp.SignatureInformation == nil ||
params.Capabilities.TextDocument.SignatureHelp.SignatureInformation.DocumentationFormat == nil {
// Default to plaintext if no preference specified
return lsproto.MarkupKindPlainText
}
formats := *params.Capabilities.TextDocument.SignatureHelp.SignatureInformation.DocumentationFormat
if len(formats) == 0 {
return lsproto.MarkupKindPlainText
}
// Return the first (most preferred) format
return formats[0]
}
5 changes: 5 additions & 0 deletions testdata/baselines/reference/fourslash/signatureHelp/jsDocFunctionSignatures5.baseline
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,7 @@
// ^
// | ----------------------------------------------------------------------
// | pathFilter(**basePath: String**, pattern: String, type: String, options: Object): any[]
// | Filters a path based on a regexp or glob pattern.
// | ----------------------------------------------------------------------
[
{
Expand All @@ -31,6 +32,10 @@
"signatures": [
{
"label": "pathFilter(basePath: String, pattern: String, type: String, options: Object): any[]",
"documentation": {
"kind": "markdown",
"value": "Filters a path based on a regexp or glob pattern."
},
"parameters": [
{
"label": "basePath: String"
Expand Down
5 changes: 5 additions & 0 deletions testdata/baselines/reference/fourslash/signatureHelp/jsdocReturnsTag.baseline
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Expand Up @@ -13,6 +13,7 @@
// ^
// | ----------------------------------------------------------------------
// | find(**l: unknown[]**, x: unknown): unknown
// | Find an item
// | ----------------------------------------------------------------------
[
{
Expand All @@ -29,6 +30,10 @@
"signatures": [
{
"label": "find(l: unknown[], x: unknown): unknown",
"documentation": {
"kind": "markdown",
"value": "Find an item"
},
"parameters": [
{
"label": "l: unknown[]"
Expand Down
20 changes: 20 additions & 0 deletions testdata/baselines/reference/fourslash/signatureHelp/signatureHelpCommentsClass.baseline
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Expand Up @@ -18,6 +18,7 @@
// ^
// | ----------------------------------------------------------------------
// | c3(): c3
// | Constructor comment
// | ----------------------------------------------------------------------
// var i3_c = c3;
// /** Class comment*/
Expand All @@ -30,6 +31,7 @@
// ^
// | ----------------------------------------------------------------------
// | c4(): c4
// | Constructor comment
// | ----------------------------------------------------------------------
// var i4_c = c4;
// /** Class with statics*/
Expand All @@ -54,6 +56,7 @@
// ^
// | ----------------------------------------------------------------------
// | c6(): c6
// | constructor comment
// | ----------------------------------------------------------------------
// var i6_c = c6;
//
Expand All @@ -69,6 +72,7 @@
// ^
// | ----------------------------------------------------------------------
// | a(**a: string**): a
// | constructor for a
// | ----------------------------------------------------------------------
// module m {
// export module m2 {
Expand Down Expand Up @@ -117,6 +121,10 @@
"signatures": [
{
"label": "c3(): c3",
"documentation": {
"kind": "markdown",
"value": "Constructor comment"
},
"parameters": []
}
],
Expand All @@ -138,6 +146,10 @@
"signatures": [
{
"label": "c4(): c4",
"documentation": {
"kind": "markdown",
"value": "Constructor comment"
},
"parameters": []
}
],
Expand Down Expand Up @@ -180,6 +192,10 @@
"signatures": [
{
"label": "c6(): c6",
"documentation": {
"kind": "markdown",
"value": "constructor comment"
},
"parameters": []
}
],
Expand All @@ -201,6 +217,10 @@
"signatures": [
{
"label": "a(a: string): a",
"documentation": {
"kind": "markdown",
"value": "constructor for a"
},
"parameters": [
{
"label": "a: string"
Expand Down
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