Fix completion of partial identifier inside a JsxExpression

src/services/completions.ts

@@ -2898,7 +2898,8 @@ function getCompletionData(
                     // First case is for `<div foo={true} [||] />` or `<div foo={true} [||] ></div>`,
                     // `parent` will be `{true}` and `previousToken` will be `}`
                     // Second case is for `<div foo={true} t[||] ></div>`
-                    if (previousToken.kind === SyntaxKind.CloseBraceToken || (previousToken.kind === SyntaxKind.Identifier || previousToken.parent.kind === SyntaxKind.JsxAttribute)) {
+                    // Second case must not match for `<div foo={undefine[||]}></div>`
+                    if (previousToken.kind === SyntaxKind.CloseBraceToken || (previousToken.kind === SyntaxKind.Identifier && previousToken.parent.kind === SyntaxKind.JsxAttribute)) {
                         isJsxIdentifierExpected = true;
                     }
                     break;

src/testRunner/tests.ts

@@ -129,6 +129,7 @@ import "./unittests/tsserver/cancellationToken";
 import "./unittests/tsserver/compileOnSave";
 import "./unittests/tsserver/completions";
 import "./unittests/tsserver/completionsIncomplete";
+import "./unittests/tsserver/completionsJsxExpression";
 import "./unittests/tsserver/configFileSearch";
 import "./unittests/tsserver/configuredProjects";
 import "./unittests/tsserver/declarationFileMaps";

src/testRunner/unittests/tsserver/completionsJsxExpression.ts

@@ -0,0 +1,60 @@
+import * as ts from "../../_namespaces/ts";
+import {
+    createServerHost,
+} from "../virtualFileSystemWithWatch";
+import {
+    baselineTsserverLogs,
+    createLoggerWithInMemoryLogs,
+    createSession,
+} from "./helpers";
+
+describe("unittests:: tsserver:: completionsJsxExpression", () => {
+    it("should not error", () => {
+        const host = createServerHost([]);
+        const session = createSession(host, {
+            canUseEvents: true,
+            noGetErrOnBackgroundUpdate: true,
+            logger: createLoggerWithInMemoryLogs(host),
+        });
+        session.executeCommandSeq<ts.server.protocol.ConfigureRequest>({
+            command: ts.server.protocol.CommandTypes.Configure,
+            arguments: {
+                preferences: {
+                    jsxAttributeCompletionStyle: "auto",
+                    includeCompletionsWithSnippetText: true,
+                }
+            }
+        });
+        session.executeCommandSeq<ts.server.protocol.UpdateOpenRequest>({
+            command: ts.server.protocol.CommandTypes.UpdateOpen,
+            arguments: {
+                changedFiles: [],
+                closedFiles: [],
+                openFiles: [
+                    {
+                        file: "^/untitled/ts-nul-authority/Untitled-1",
+                        fileContent: `interface IntrinsicElements { div: { foo?: number } }\n<div foo={undefine}></div>`,
+                        scriptKindName: "TSX"
+                    }
+                ]
+            }
+        });
+        const completion = session.executeCommandSeq<ts.server.protocol.CompletionsRequest>({
+            command: ts.server.protocol.CommandTypes.CompletionInfo,
+            arguments: {
+                file: "^/untitled/ts-nul-authority/Untitled-1",
+                line: 2,
+                offset: 19,
+                includeInsertTextCompletions: true,
+            }
+        }).response as ts.server.protocol.CompletionInfo | undefined;
+        baselineTsserverLogs("completionsJsxExpression", "should not complete as jsx attribute", session);
+        ts.Debug.assertIsDefined(completion);
+        for (const entry of completion.entries) {
+            ts.Debug.assert(!entry.isSnippet);
+            if (entry.insertText) {
+                ts.Debug.assert(!entry.insertText.includes("="));
+            }
+        }
+    });
+});