Fixes #3682 - Fix $ne filters incorrectly excluding null values (#3686)

* allow matching null values when not equals query filter is set

* Also fix namedParameter queries with  filter

* improve tests

* release note

---------

Co-authored-by: Joel Rich <joelrich@protonmail.com>

packages/loot-core/src/server/aql/compiler.ts

@@ -706,12 +706,12 @@ const compileOp = saveStack('op', (state, fieldRef, opData) => {
         state.namedParameters = [].concat.apply([], orders);
 
         return `CASE
-          WHEN ${left} IS NULL THEN ${right} IS NULL
-          ELSE ${left} != ${right}
+          WHEN ${left} IS NULL THEN ${right} IS NOT NULL
+          ELSE ${left} IS NOT ${right}
         END`;
       }
 
-      return `${left} != ${right}`;
+      return `(${left} != ${right} OR ${left} IS NULL)`;
     }
     case '$oneof': {
       const [left, right] = valArray(state, [lhs, rhs], [null, 'array']);

packages/loot-core/src/server/aql/exec.test.ts

@@ -167,6 +167,7 @@ describe('runQuery', () => {
   it('allows null as a parameter', async () => {
     await db.insertCategoryGroup({ id: 'group', name: 'group' });
     await db.insertCategory({ id: 'cat', name: 'cat', cat_group: 'group' });
+    await db.insertCategory({ id: 'cat2', name: 'cat2', cat_group: 'group' });
     const transNoCat = await db.insertTransaction({
       account: 'acct',
       date: '2020-01-01',
@@ -179,6 +180,12 @@ describe('runQuery', () => {
       amount: -5001,
       category: 'cat',
     });
+    const transCat2 = await db.insertTransaction({
+      account: 'acct',
+      date: '2020-01-02',
+      amount: -5001,
+      category: 'cat2',
+    });
 
     const queryState = q('transactions')
       .filter({ category: ':category' })
@@ -190,6 +197,43 @@ describe('runQuery', () => {
 
     data = (await runQuery(queryState, { params: { category: 'cat' } })).data;
     expect(data[0].id).toBe(transCat);
+
+    data = (
+      await runQuery(
+        q('transactions')
+          .filter({ category: { $ne: ':category' } })
+          .select('category')
+          .serialize(),
+
+        { params: { category: 'cat2' } },
+      )
+    ).data;
+    expect(data).toHaveLength(2);
+    expect(data).toEqual(
+      expect.arrayContaining([
+        expect.objectContaining({ id: transNoCat }),
+        expect.objectContaining({ id: transCat }),
+        expect.not.objectContaining({ id: transCat2 }),
+      ]),
+    );
+
+    data = (
+      await runQuery(
+        q('transactions')
+          .filter({ category: { $ne: ':category' } })
+          .select('category')
+          .serialize(),
+        { params: { category: null } },
+      )
+    ).data;
+    expect(data).toHaveLength(2);
+    expect(data).toEqual(
+      expect.arrayContaining([
+        expect.not.objectContaining({ id: transNoCat }),
+        expect.objectContaining({ id: transCat }),
+        expect.objectContaining({ id: transCat2 }),
+      ]),
+    );
   });
 
   it('parameters have the correct order', async () => {

upcoming-release-notes/3686.md

@@ -0,0 +1,6 @@
+---
+category: Bugfix
+authors: [joel-rich]
+---
+
+Fixes #3682 - Fix $ne filters incorrectly excluding null values