Fix invalidation bug where jsonb "null" was being conflated with SQL NULL (#3861)

* Fix invalidation bug where string "null" was being conflated with SQL NULL

* fix test

Author: habdelra

packages/realm-server/tests/indexing-test.ts

@@ -1373,6 +1373,22 @@ module(basename(__filename), function () {
         'instance',
         'instance is repaired when missing module is added',
       );
+      let rows = (await testDbAdapter.execute(
+        `SELECT error_doc IS NULL AS is_sql_null
+         FROM boxel_index
+         WHERE realm_url = '${testRealm}'
+           AND (
+             url = '${testRealm}deep-card.json'
+             OR file_alias = '${testRealm}deep-card'
+           )
+           AND type = 'instance'`,
+      )) as { is_sql_null: boolean }[];
+      assert.strictEqual(
+        rows.length,
+        1,
+        'index row exists for deep-card instance',
+      );
+      assert.true(rows[0].is_sql_null, 'error_doc is SQL NULL after recovery');
     });
 
     test('can incrementally index deleted instance', async function (assert) {

packages/runtime-common/expression.ts

@@ -277,14 +277,12 @@ export function asExpressions(
   valueExpressions: Param[][];
 } {
   let paramBucket = Object.fromEntries(
-    Object.entries(values).map(([col, val]) => [
-      col,
-      param(
-        opts?.jsonFields?.includes(col)
-          ? stringify(val ?? null)
-          : (val ?? null),
-      ),
-    ]),
+    Object.entries(values).map(([col, val]) => {
+      if (opts?.jsonFields?.includes(col)) {
+        return [col, param(val == null ? null : (stringify(val) ?? null))];
+      }
+      return [col, param(val ?? null)];
+    }),
   );
   let nameExpressions = Object.keys(paramBucket).map((name) => [name]);
   let valueExpressions = Object.keys(paramBucket).map((k) => {