sql: make result array metadata properties non-enumerable

src/js/internal/sql/shared.ts

@@ -78,10 +78,11 @@ class SQLArrayParameter {
 }
 
 class SQLResultArray<T> extends PublicArray<T> {
-  public count!: number | null;
-  public command!: string | null;
-  public lastInsertRowid!: number | bigint | null;
-  public affectedRows!: number | bigint | null;
+  // Types only: real class fields would be defined (enumerable) after super() and redefined below.
+  declare count: number | null;
+  declare command: string | null;
+  declare lastInsertRowid: number | bigint | null;
+  declare affectedRows: number | bigint | null;
 
   static [Symbol.toStringTag] = "SQLResults";
 
@@ -91,10 +92,10 @@ class SQLResultArray<T> extends PublicArray<T> {
     // match postgres's result array, in this way for in will not list the
     // properties and .map will not return undefined command and count
     Object.defineProperties(this, {
-      count: { value: null, writable: true },
-      command: { value: null, writable: true },
-      lastInsertRowid: { value: null, writable: true },
-      affectedRows: { value: null, writable: true },
+      count: { value: null, writable: true, enumerable: false, configurable: true },
+      command: { value: null, writable: true, enumerable: false, configurable: true },
+      lastInsertRowid: { value: null, writable: true, enumerable: false, configurable: true },
+      affectedRows: { value: null, writable: true, enumerable: false, configurable: true },
     });
   }
 

test/js/sql/sql-mysql.test.ts

@@ -176,6 +176,31 @@ if (isDockerEnabled()) {
             await sql`UPDATE ${sql(random_name)} SET name = "test2" WHERE id = ${lastInsertRowid}`;
           expect(affectedRows).toBe(1);
         });
+        test("result metadata properties are not enumerable", async () => {
+          await using db = new SQL({ ...getOptions(), max: 1, idleTimeout: 5 });
+          using sql = await db.reserve();
+          const t = "meta_" + randomUUIDv7("hex").replaceAll("-", "");
+          await sql`CREATE TEMPORARY TABLE ${sql(t)} (id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, name text)`;
+
+          const inserted = await sql`INSERT INTO ${sql(t)} (name) VALUES (${"test"})`;
+          expect(Object.keys(inserted)).toEqual([]);
+          expect(
+            ["lastInsertRowid", "affectedRows"].map(key => Object.getOwnPropertyDescriptor(inserted, key)),
+          ).toEqual([
+            { value: 1, writable: true, enumerable: false, configurable: true },
+            { value: 1, writable: true, enumerable: false, configurable: true },
+          ]);
+
+          const selected = await sql`SELECT id, name FROM ${sql(t)}`;
+          expect(selected).toEqual([{ id: 1, name: "test" }]);
+          expect(Object.keys(selected)).toEqual(["0"]);
+          expect(Object.getOwnPropertyDescriptor(selected, "count")).toEqual({
+            value: 1,
+            writable: true,
+            enumerable: false,
+            configurable: true,
+          });
+        });
         test("MEDIUMINT not in the last column reads following columns correctly", async () => {
           // MySQL's binary protocol sends MYSQL_TYPE_INT24 as a fixed 4-byte
           // field. Reading only 3 left the cursor 1 byte behind, silently

test/js/sql/sql.test.ts

@@ -976,6 +976,18 @@ if (isDockerEnabled()) {
       expect((await sql`select 1`).command).toBe("SELECT");
     });
 
+    test("Result metadata is not enumerable", async () => {
+      const result = await sql`select 1 as x`;
+      expect(Object.keys(result)).toEqual(["0"]);
+      const metadata = ["count", "command", "lastInsertRowid", "affectedRows"];
+      expect(metadata.map(key => Object.getOwnPropertyDescriptor(result, key))).toEqual([
+        { value: 1, writable: true, enumerable: false, configurable: true },
+        { value: "SELECT", writable: true, enumerable: false, configurable: true },
+        { value: null, writable: true, enumerable: false, configurable: true },
+        { value: null, writable: true, enumerable: false, configurable: true },
+      ]);
+    });
+
     test("Create table", async () => {
       await sql`create table test(int int)`;
       await sql`drop table test`;

test/js/sql/sqlite-sql.test.ts

@@ -872,6 +872,38 @@ describe("Query Execution", () => {
     expect(result.command).toBe("DELETE");
   });
 
+  test("result metadata properties are not enumerable", async () => {
+    await sql`CREATE TABLE result_metadata (id INTEGER PRIMARY KEY, name TEXT)`;
+    const inserted = await sql`INSERT INTO result_metadata (name) VALUES (${"a"}), (${"b"})`;
+    const selected = await sql`SELECT * FROM result_metadata ORDER BY id`;
+
+    // Like postgres.js, the metadata hangs off the array without showing up
+    // when the rows are enumerated.
+    expect(Object.keys(selected)).toEqual(["0", "1"]);
+    expect(Object.keys(inserted)).toEqual([]);
+    const forIn: string[] = [];
+    for (const key in selected) forIn.push(key);
+    expect(forIn).toEqual(["0", "1"]);
+    expect({ ...selected }).toEqual({
+      "0": { id: 1, name: "a" },
+      "1": { id: 2, name: "b" },
+    });
+
+    const metadata = ["count", "command", "lastInsertRowid", "affectedRows"];
+    expect(metadata.map(key => Object.getOwnPropertyDescriptor(selected, key))).toEqual([
+      { value: 2, writable: true, enumerable: false, configurable: true },
+      { value: "SELECT", writable: true, enumerable: false, configurable: true },
+      { value: null, writable: true, enumerable: false, configurable: true },
+      { value: null, writable: true, enumerable: false, configurable: true },
+    ]);
+    expect(metadata.map(key => Object.getOwnPropertyDescriptor(inserted, key))).toEqual([
+      { value: 2, writable: true, enumerable: false, configurable: true },
+      { value: "INSERT", writable: true, enumerable: false, configurable: true },
+      { value: 2, writable: true, enumerable: false, configurable: true },
+      { value: null, writable: true, enumerable: false, configurable: true },
+    ]);
+  });
+
   test("SELECT with various clauses", async () => {
     await sql`CREATE TABLE scores (id INTEGER, player TEXT, score INTEGER, team TEXT)`;
     await sql`INSERT INTO scores VALUES