Align empty sub query and empty append handling across stores

src/Store/InMemoryStore.php

@@ -123,6 +123,10 @@ public function append(iterable $messages, AppendCondition|null $appendCondition
             ? iterator_to_array($messages, false)
             : array_values($messages);
 
+        if ($messages === []) {
+            return;
+        }
+
         $this->transactional(function () use ($messages, $appendCondition): void {
             if ($appendCondition instanceof AppendCondition && $appendCondition->highestSequenceNumber !== null) {
                 $matched = $this->matchQuery($appendCondition->query);

src/Store/TaggableDoctrineDbalStore.php

@@ -468,6 +468,10 @@ public function append(iterable $messages, AppendCondition|null $appendCondition
                 $position++;
             }
 
+            if ($selects === []) {
+                return;
+            }
+
             // The rows are wrapped in a derived table so that the append condition
             // below applies to the whole batch. Appending it straight after a
             // `UNION ALL` chain would bind it to the last SELECT only, letting every
@@ -882,15 +886,17 @@ private function queryCondition(QueryBuilder $builder, Query $query): void
             return;
         }
 
+        foreach ($query->subQueries as $subQuery) {
+            if ($subQuery->empty() && !$subQuery->onlyLastEvent) {
+                return; // an empty sub query matches all events, same as SubQuery::match()
+            }
+        }
+
         $subqueries = [];
 
         $uniqueParameterGenerator = $this->uniqueParameterGenerator();
 
         foreach ($query->subQueries as $subQuery) {
-            if ($subQuery->empty()) {
-                continue;
-            }
-
             $subQueryBuilder = $this->connection->createQueryBuilder()
                 ->select('id')
                 ->from($this->config['table_name']);
@@ -940,10 +946,6 @@ private function queryCondition(QueryBuilder $builder, Query $query): void
             $subqueries[] = $subQueryBuilder->getSQL();
         }
 
-        if ($subqueries === []) {
-            return;
-        }
-
         $joinQueryBuilder = $this->connection->createQueryBuilder()
             ->select('id')
             ->from('(' . implode(' UNION ALL ', $subqueries) . ')', 'j')

tests/Integration/Store/TaggableDoctrineDbalStoreTest.php

@@ -774,6 +774,57 @@ public function testOnlyLastEvent(): void
         self::assertStreamEquals([$message2], $stream);
     }
 
+    public function testQueryWithEmptySubQueryMatchesAll(): void
+    {
+        $profileId1 = ProfileId::generate();
+        $profileId2 = ProfileId::generate();
+
+        $message1 = Message::create(new ProfileCreated($profileId1, 'test'))
+            ->withHeader(new StreamNameHeader('foo'))
+            ->withHeader(new RecordedOnHeader(new DateTimeImmutable('2020-01-01 00:00:00')))
+            ->withHeader(new TagsHeader(['profile:' . $profileId1->toString()]));
+        $message2 = Message::create(new ProfileCreated($profileId2, 'test'))
+            ->withHeader(new StreamNameHeader('foo'))
+            ->withHeader(new RecordedOnHeader(new DateTimeImmutable('2020-01-01 00:00:00')))
+            ->withHeader(new TagsHeader(['profile:' . $profileId2->toString()]));
+
+        $this->store->append([$message1, $message2]);
+
+        $stream = $this->store->query(new Query(
+            new SubQuery(),
+            new SubQuery(['profile:' . $profileId1->toString()]),
+        ));
+
+        self::assertStreamEquals([$message1, $message2], $stream);
+    }
+
+    public function testQueryWithEmptyOnlyLastEventSubQuery(): void
+    {
+        $profileId1 = ProfileId::generate();
+        $profileId2 = ProfileId::generate();
+
+        $message1 = Message::create(new ProfileCreated($profileId1, 'test'))
+            ->withHeader(new StreamNameHeader('foo'))
+            ->withHeader(new RecordedOnHeader(new DateTimeImmutable('2020-01-01 00:00:00')))
+            ->withHeader(new TagsHeader(['profile:' . $profileId1->toString()]));
+        $message2 = Message::create(new ProfileCreated($profileId2, 'test'))
+            ->withHeader(new StreamNameHeader('foo'))
+            ->withHeader(new RecordedOnHeader(new DateTimeImmutable('2020-01-01 00:00:00')))
+            ->withHeader(new TagsHeader(['profile:' . $profileId2->toString()]));
+        $message3 = Message::create(new ExternEvent('test message'))
+            ->withHeader(new StreamNameHeader('foo'))
+            ->withHeader(new TagsHeader([]));
+
+        $this->store->append([$message1, $message2, $message3]);
+
+        $stream = $this->store->query(new Query(
+            new SubQuery(onlyLastEvent: true),
+            new SubQuery(['profile:' . $profileId1->toString()]),
+        ));
+
+        self::assertStreamEquals([$message1, $message3], $stream);
+    }
+
     public function testComplexQuery(): void
     {
         $profileId1 = ProfileId::generate();
@@ -984,6 +1035,51 @@ public function testAppendWithEmptyQuery(): void
         self::assertStreamEquals([...$messages, $message], $this->store->load());
     }
 
+    public function testAppendWithoutMessages(): void
+    {
+        $profileId = ProfileId::generate();
+
+        $message = Message::create(new ProfileCreated($profileId, 'test'))
+            ->withHeader(new StreamNameHeader('foo'))
+            ->withHeader(new RecordedOnHeader(new DateTimeImmutable('2020-01-01 00:00:00')))
+            ->withHeader(new TagsHeader(['profile:' . $profileId->toString()]));
+
+        $this->store->append([$message]);
+        $this->store->append([]);
+        $this->store->append([], new AppendCondition(new Query(), 0));
+
+        self::assertStreamEquals([$message], $this->store->load());
+    }
+
+    public function testAppendConditionWithEmptySubQuery(): void
+    {
+        $profileId = ProfileId::generate();
+
+        $message1 = Message::create(new ProfileCreated($profileId, 'test'))
+            ->withHeader(new StreamNameHeader('foo'))
+            ->withHeader(new RecordedOnHeader(new DateTimeImmutable('2020-01-01 00:00:00')))
+            ->withHeader(new TagsHeader(['profile:' . $profileId->toString()]));
+
+        $this->store->append([$message1]);
+
+        $message2 = Message::create(new ExternEvent('test message'))
+            ->withHeader(new StreamNameHeader('foo'))
+            ->withHeader(new TagsHeader([]));
+
+        $this->expectException(AppendConditionNotMet::class);
+
+        $this->store->append(
+            [$message2],
+            new AppendCondition(
+                new Query(
+                    new SubQuery(),
+                    new SubQuery(['unknown']),
+                ),
+                0,
+            ),
+        );
+    }
+
     public function testStreams(): void
     {
         $profileId = ProfileId::fromString('0190e47e-77e9-7b90-bf62-08bbf0ab9b4b');

tests/Unit/Store/InMemoryStoreTest.php

@@ -733,6 +733,43 @@ public function testQueryOnlyLastEvent(): void
         self::assertSame([$message2], $stream->toList());
     }
 
+    public function testQueryWithEmptySubQueryMatchesAll(): void
+    {
+        $message1 = $this->message(new ProfileVisited(ProfileId::fromString('1')), 1, ['profile-1']);
+        $message2 = $this->message(new ProfileVisited(ProfileId::fromString('2')), 2, ['profile-2']);
+
+        $store = new InMemoryStore([$message1, $message2]);
+
+        $stream = $store->query(new Query(new SubQuery(), new SubQuery(['profile-1'])));
+
+        self::assertSame([$message1, $message2], $stream->toList());
+    }
+
+    public function testQueryWithEmptyOnlyLastEventSubQuery(): void
+    {
+        $message1 = $this->message(new ProfileVisited(ProfileId::fromString('1')), 1, ['profile-1']);
+        $message2 = $this->message(new ProfileVisited(ProfileId::fromString('2')), 2, ['profile-2']);
+        $message3 = $this->message(new ProfileVisited(ProfileId::fromString('3')), 3, ['profile-3']);
+
+        $store = new InMemoryStore([$message1, $message2, $message3]);
+
+        $stream = $store->query(new Query(new SubQuery(onlyLastEvent: true), new SubQuery(['profile-1'])));
+
+        self::assertSame([$message1, $message3], $stream->toList());
+    }
+
+    public function testAppendWithoutMessages(): void
+    {
+        $message = $this->message(new ProfileVisited(ProfileId::fromString('1')), 1, ['profile-1']);
+
+        $store = new InMemoryStore([$message]);
+
+        $store->append([]);
+        $store->append([], new AppendCondition(new Query(), 0));
+
+        self::assertSame([$message], $store->load()->toList());
+    }
+
     public function testAppendAssignsIndex(): void
     {
         $store = new InMemoryStore();