fix: Check for empty row in mysql2 driver

This is a port of the fix in sqlc-dev#18 but for the mysql2 driver.

Author: arnested

examples/bun-mysql2/src/db/query_sql.ts

@@ -28,6 +28,9 @@ export async function getAuthor(client: Client, args: GetAuthorArgs): Promise<Ge
         return null;
     }
     const row = rows[0];
+    if (!row) {
+        return null;
+    }
     return {
         id: row[0],
         name: row[1],
@@ -168,6 +171,9 @@ export async function test(client: Client): Promise<TestRow | null> {
         return null;
     }
     const row = rows[0];
+    if (!row) {
+        return null;
+    }
     return {
         cBit: row[0],
         cTinyint: row[1],

examples/node-mysql2/src/db/query_sql.ts

@@ -28,6 +28,9 @@ export async function getAuthor(client: Client, args: GetAuthorArgs): Promise<Ge
         return null;
     }
     const row = rows[0];
+    if (!row) {
+        return null;
+    }
     return {
         id: row[0],
         name: row[1],
@@ -168,6 +171,9 @@ export async function test(client: Client): Promise<TestRow | null> {
         return null;
     }
     const row = rows[0];
+    if (!row) {
+        return null;
+    }
     return {
         cBit: row[0],
         cTinyint: row[1],

src/drivers/mysql2.ts

@@ -627,6 +627,17 @@ export class Driver {
                 NodeFlags.TypeExcludesFlags
             )
           ),
+	  factory.createIfStatement(
+            factory.createPrefixUnaryExpression(
+              SyntaxKind.ExclamationToken,
+              factory.createIdentifier("row")
+            ),
+            factory.createBlock(
+              [factory.createReturnStatement(factory.createNull())],
+              true
+            ),
+            undefined
+          ),
           factory.createReturnStatement(
             factory.createObjectLiteralExpression(
               columns.map((col, i) =>