Make un-awaited getAll() fail loudly instead of yielding {}

src_js/lbug.d.ts

@@ -394,7 +394,9 @@ export class QueryResult {
     getNumTuples(): number;
 
     /**
-     * Get the next row.
+     * Get the next row. This method is asynchronous and must be awaited
+     * (`await result.getNext()`); in synchronous code, use `getNextSync()`
+     * instead.
      * @returns Promise that resolves to the next row or null if no more rows
      */
     getNext(): Promise<Record<string, LbugValue> | null>;
@@ -419,6 +421,12 @@ export class QueryResult {
 
     /**
      * Get all rows of the query result.
+     *
+     * WARNING: this method is asynchronous and must be awaited
+     * (`await result.getAll()`). Using it without `await` yields a pending
+     * Promise (which `JSON.stringify` renders as `{}`), not the rows;
+     * serializing that Promise throws an error pointing here. In synchronous
+     * code, use `getAllSync()` instead.
      * @returns Promise that resolves to all rows
      */
     getAll(): Promise<Record<string, LbugValue>[]>;
@@ -440,7 +448,8 @@ export class QueryResult {
     ): void;
 
     /**
-     * Get the column data types.
+     * Get the column data types. This method is asynchronous and must be
+     * awaited; in synchronous code, use `getColumnDataTypesSync()` instead.
      * @returns Promise that resolves to array of data type strings
      */
     getColumnDataTypes(): Promise<string[]>;
@@ -452,7 +461,8 @@ export class QueryResult {
     getColumnDataTypesSync(): string[];
 
     /**
-     * Get the column names.
+     * Get the column names. This method is asynchronous and must be awaited;
+     * in synchronous code, use `getColumnNamesSync()` instead.
      * @returns Promise that resolves to array of column names
      */
     getColumnNames(): Promise<string[]>;

src_js/query_result.js

@@ -2,6 +2,24 @@
 
 const assert = require("assert");
 
+const GET_ALL_AWAIT_MESSAGE =
+  "QueryResult.getAll() returns a Promise and must be awaited " +
+  "(`await result.getAll()`). In synchronous code, use `result.getAllSync()` instead. " +
+  "Serializing the un-awaited Promise (e.g. via JSON.stringify, which renders it as '{}') " +
+  "is almost certainly a bug.";
+
+/**
+ * Promise returned by QueryResult.getAll(). Behaves exactly like a native
+ * Promise, except that serializing it (e.g. via JSON.stringify, which renders
+ * a plain pending Promise as '{}') throws a descriptive error instead of
+ * silently producing '{}' that looks like an empty result.
+ */
+class GetAllPromise extends Promise {
+  toJSON() {
+    throw new Error(GET_ALL_AWAIT_MESSAGE);
+  }
+}
+
 class QueryResult {
   /**
    * Internal constructor. Use `Connection.query` or `Connection.execute`
@@ -51,7 +69,9 @@ class QueryResult {
   }
 
   /**
-   * Get the next row of the query result.
+   * Get the next row of the query result. This method is asynchronous and must
+   * be awaited (`await result.getNext()`); in synchronous code, use
+   * `getNextSync()` instead.
    * @returns {Promise<Object>} a promise that resolves to the next row of the query result. The promise is rejected if there is an error.
    */
   getNext() {
@@ -98,16 +118,26 @@ class QueryResult {
 
   /**
    * Get all rows of the query result.
+   *
+   * WARNING: this method is asynchronous and returns a Promise — it must be
+   * awaited (`await result.getAll()`). Using it without `await` yields a
+   * pending Promise (which `JSON.stringify` renders as `{}`), not the rows;
+   * serializing that Promise throws an error pointing here. In synchronous
+   * code, use `getAllSync()` instead.
    * @returns {Promise<Array<Object>>} a promise that resolves to all rows of the query result. The promise is rejected if there is an error.
    */
-  async getAll() {
-    this._checkClosed();
-    this._queryResult.resetIterator();
-    const result = [];
-    while (this.hasNext()) {
-      result.push(await this.getNext());
-    }
-    return result;
+  getAll() {
+    return new GetAllPromise((resolve, reject) => {
+      (async () => {
+        this._checkClosed();
+        this._queryResult.resetIterator();
+        const result = [];
+        while (this.hasNext()) {
+          result.push(await this.getNext());
+        }
+        return result;
+      })().then(resolve, reject);
+    });
   }
 
   /**
@@ -141,7 +171,9 @@ class QueryResult {
   }
 
   /**
-   * Get the data types of the columns of the query result.
+   * Get the data types of the columns of the query result. This method is
+   * asynchronous and must be awaited; in synchronous code, use
+   * `getColumnDataTypesSync()` instead.
    * @returns {Promise<Array<String>>} a promise that resolves to the data types of the columns of the query result. The promise is rejected if there is an error.
    */
   getColumnDataTypes() {
@@ -166,7 +198,9 @@ class QueryResult {
   }
 
   /**
-   * Get the names of the columns of the query result.
+   * Get the names of the columns of the query result. This method is
+   * asynchronous and must be awaited; in synchronous code, use
+   * `getColumnNamesSync()` instead.
    * @returns {Promise<Array<String>>} a promise that resolves to the names of the columns of the query result. The promise is rejected if there is an error.
    */
   getColumnNames() {
@@ -192,6 +226,8 @@ class QueryResult {
 
   /**
    * Get the query summary (compiling and execution time) of the query result.
+   * This method is asynchronous and must be awaited; in synchronous code, use
+   * `getQuerySummarySync()` instead.
    * @returns {Promise<Object>} a promise that resolves to the query summary of the query result. The promise is rejected if there is an error.
    */
   getQuerySummary() {

test/test_query_result.js

@@ -133,6 +133,18 @@ describe("Get all", function () {
     const ids = tuples.map((tuple) => tuple["a.ID"]);
     assert.deepEqual(ids, PERSON_IDS);
   });
+
+  it("should fail loudly instead of silently returning {} when not awaited", async function () {
+    const queryResult = await conn.query(
+      "MATCH (a:person) RETURN a.ID ORDER BY a.ID"
+    );
+    const pending = queryResult.getAll();
+    assert.instanceOf(pending, Promise);
+    assert.throws(() => JSON.stringify(pending), /getAllSync/);
+    const tuples = await pending;
+    const ids = tuples.map((tuple) => tuple["a.ID"]);
+    assert.deepEqual(ids, PERSON_IDS);
+  });
 });
 
 describe("All", function () {

test/test_sync_api.js

@@ -92,6 +92,20 @@ describe("Query execution", function () {
 
 
 describe("Query result", function () {
+  it("should fail loudly when getAll() is used without await in sync code", async function () {
+    const queryResult = conn.querySync(
+      "MATCH (a:person) RETURN a.ID ORDER BY a.ID"
+    );
+    const pending = queryResult.getAll();
+    assert.instanceOf(pending, Promise);
+    assert.throws(() => JSON.stringify(pending), /getAllSync/);
+    const rows = await pending;
+    assert.equal(rows.length, PERSON_IDS.length);
+    for (let i = 0; i < PERSON_IDS.length; ++i) {
+      assert.equal(rows[i]["a.ID"], PERSON_IDS[i]);
+    }
+  });
+
   it("should get all rows of a query result synchronously", function () {
     const queryResult = conn.querySync(
       "MATCH (a:person) RETURN a.ID ORDER BY a.ID"