Fix panic when hovering over functions with JSDoc links

internal/ast/ast.go

@@ -309,6 +309,12 @@ func (n *Node) Text() string {
 		return n.AsRegularExpressionLiteral().Text
 	case KindJSDocText:
 		return strings.Join(n.AsJSDocText().text, "")
+	case KindJSDocLink:
+		return strings.Join(n.AsJSDocLink().text, "")
+	case KindJSDocLinkCode:
+		return strings.Join(n.AsJSDocLinkCode().text, "")
+	case KindJSDocLinkPlain:
+		return strings.Join(n.AsJSDocLinkPlain().text, "")
 	}
 	panic(fmt.Sprintf("Unhandled case in Node.Text: %T", n.data))
 }

internal/ls/hover.go

@@ -407,6 +407,30 @@ func writeComments(b *strings.Builder, comments []*ast.Node) {
 				}
 			}
 			b.WriteString(text)
+		case ast.KindJSDocLinkCode:
+			// !!! TODO: This is a temporary placeholder implementation that needs to be updated later
+			name := comment.Name()
+			text := comment.AsJSDocLinkCode().Text()
+			if name != nil {
+				if text == "" {
+					writeEntityName(b, name)
+				} else {
+					writeEntityNameParts(b, name)
+				}
+			}
+			b.WriteString(text)
+		case ast.KindJSDocLinkPlain:
+			// !!! TODO: This is a temporary placeholder implementation that needs to be updated later
+			name := comment.Name()
+			text := comment.AsJSDocLinkPlain().Text()
+			if name != nil {
+				if text == "" {
+					writeEntityName(b, name)
+				} else {
+					writeEntityNameParts(b, name)
+				}
+			}
+			b.WriteString(text)
 		}
 	}
 }

internal/ls/hover_test.go

@@ -0,0 +1,97 @@
+package ls_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/microsoft/typescript-go/internal/bundled"
+	"github.com/microsoft/typescript-go/internal/core"
+	"github.com/microsoft/typescript-go/internal/fourslash"
+	"github.com/microsoft/typescript-go/internal/ls"
+	"github.com/microsoft/typescript-go/internal/lsp/lsproto"
+	"github.com/microsoft/typescript-go/internal/testutil/projecttestutil"
+	"gotest.tools/v3/assert"
+)
+
+func TestHover(t *testing.T) {
+	t.Parallel()
+	if !bundled.Embedded {
+		// Without embedding, we'd need to read all of the lib files out from disk into the MapFS.
+		// Just skip this for now.
+		t.Skip("bundled files are not embedded")
+	}
+
+	testCases := []struct {
+		title    string
+		input    string
+		expected map[string]*lsproto.Hover
+	}{
+		{
+			title: "JSDocLinksPanic",
+			input: `
+// @filename: index.ts
+/**
+ * A function with JSDoc links that previously caused panic
+ * {@link console.log} and {@linkcode Array.from} and {@linkplain Object.keys}
+ */
+function myFunction() {
+    return "test";
+}
+
+/*marker*/myFunction();`,
+			expected: map[string]*lsproto.Hover{
+				"marker": {
+					Contents: lsproto.MarkupContentOrMarkedStringOrMarkedStrings{
+						MarkupContent: &lsproto.MarkupContent{
+							Kind:  lsproto.MarkupKindMarkdown,
+							Value: "```tsx\nfunction myFunction(): string\n```\nA function with JSDoc links that previously caused panic\n`console.log` and `Array.from` and `Object.keys`\n",
+						},
+					},
+				},
+			},
+		},
+	}
+
+	for _, testCase := range testCases {
+		t.Run(testCase.title, func(t *testing.T) {
+			t.Parallel()
+			runHoverTest(t, testCase.input, testCase.expected)
+		})
+	}
+}
+
+func runHoverTest(t *testing.T, input string, expected map[string]*lsproto.Hover) {
+	testData := fourslash.ParseTestData(t, input, "/mainFile.ts")
+	file := testData.Files[0].FileName()
+	markerPositions := testData.MarkerPositions
+	ctx := projecttestutil.WithRequestID(t.Context())
+	languageService, done := createLanguageServiceForHover(ctx, file, map[string]any{
+		file: testData.Files[0].Content,
+	})
+	defer done()
+
+	for markerName, expectedResult := range expected {
+		marker, ok := markerPositions[markerName]
+		if !ok {
+			t.Fatalf("No marker found for '%s'", markerName)
+		}
+		result, err := languageService.ProvideHover(
+			ctx,
+			ls.FileNameToDocumentURI(file),
+			marker.LSPosition)
+		assert.NilError(t, err)
+		if expectedResult == nil {
+			assert.Assert(t, result == nil)
+		} else {
+			assert.Assert(t, result != nil)
+			assert.DeepEqual(t, *result, *expectedResult)
+		}
+	}
+}
+
+func createLanguageServiceForHover(ctx context.Context, fileName string, files map[string]any) (*ls.LanguageService, func()) {
+	projectService, _ := projecttestutil.Setup(files, nil)
+	projectService.OpenFile(fileName, files[fileName].(string), core.GetScriptKindFromFileName(fileName), "")
+	project := projectService.Projects()[0]
+	return project.GetLanguageServiceForRequest(ctx)
+}