Expand bounds for distinct and MongoIterable#map (#1352)

Allow for nullable types in those scenarios.

JAVA-5358

driver-kotlin-coroutine/build.gradle.kts

@@ -75,6 +75,7 @@ dependencies {
     testImplementation("io.github.classgraph:classgraph:4.8.154")
 
     integrationTestImplementation("org.jetbrains.kotlin:kotlin-test-junit")
+    integrationTestImplementation("org.jetbrains.kotlinx:kotlinx-coroutines-test")
     integrationTestImplementation(project(path = ":driver-sync"))
     integrationTestImplementation(project(path = ":driver-core"))
     integrationTestImplementation(project(path = ":bson"))

driver-kotlin-coroutine/src/integration/kotlin/com/mongodb/kotlin/client/coroutine/SmokeTests.kt

@@ -0,0 +1,101 @@
+/*
+ * Copyright 2008-present MongoDB, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.mongodb.kotlin.client.coroutine
+
+import com.mongodb.client.Fixture.getDefaultDatabaseName
+import com.mongodb.client.Fixture.getMongoClientSettings
+import kotlin.test.assertContentEquals
+import kotlin.test.assertEquals
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.toList
+import kotlinx.coroutines.flow.toSet
+import kotlinx.coroutines.runBlocking
+import kotlinx.coroutines.test.runTest
+import org.bson.Document
+import org.junit.jupiter.api.AfterAll
+import org.junit.jupiter.api.AfterEach
+import org.junit.jupiter.api.BeforeAll
+import org.junit.jupiter.api.DisplayName
+import org.junit.jupiter.api.Test
+
+@OptIn(ExperimentalCoroutinesApi::class)
+class SmokeTests {
+
+    @AfterEach
+    fun afterEach() {
+        runBlocking { database?.drop() }
+    }
+
+    @Test
+    @DisplayName("distinct and return nulls")
+    fun testDistinctNullable() = runTest {
+        collection!!.insertMany(
+            listOf(
+                Document.parse("{_id: 1, a: 0}"),
+                Document.parse("{_id: 2, a: 1}"),
+                Document.parse("{_id: 3, a: 0}"),
+                Document.parse("{_id: 4, a: null}")))
+
+        // nulls are auto excluded in reactive streams!
+        val actual = collection!!.distinct<Int>("a").toSet()
+        assertEquals(setOf(0, 1), actual)
+    }
+
+    @Test
+    @DisplayName("mapping can return nulls")
+    fun testMongoIterableMap() = runTest {
+        collection!!.insertMany(
+            listOf(
+                Document.parse("{_id: 1, a: 0}"),
+                Document.parse("{_id: 2, a: 1}"),
+                Document.parse("{_id: 3, a: 0}"),
+                Document.parse("{_id: 4, a: null}")))
+
+        val actual = collection!!.find().map { it["a"] as Int? }.toList()
+        assertContentEquals(listOf(0, 1, 0, null), actual)
+    }
+
+    companion object {
+
+        private var mongoClient: MongoClient? = null
+        private var database: MongoDatabase? = null
+        private var collection: MongoCollection<Document>? = null
+
+        @BeforeAll
+        @JvmStatic
+        internal fun beforeAll() {
+            runBlocking {
+                mongoClient = MongoClient.create(getMongoClientSettings())
+                database = mongoClient?.getDatabase(getDefaultDatabaseName())
+                database?.drop()
+                collection = database?.getCollection("SmokeTests")
+            }
+        }
+
+        @AfterAll
+        @JvmStatic
+        internal fun afterAll() {
+            runBlocking {
+                collection = null
+                database?.drop()
+                database = null
+                mongoClient?.close()
+                mongoClient = null
+            }
+        }
+    }
+}

driver-kotlin-sync/src/integration/kotlin/com/mongodb/kotlin/client/SmokeTests.kt

@@ -0,0 +1,89 @@
+/*
+ * Copyright 2008-present MongoDB, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.mongodb.kotlin.client
+
+import com.mongodb.client.Fixture.getDefaultDatabaseName
+import com.mongodb.client.Fixture.getMongoClientSettings
+import kotlin.test.assertContentEquals
+import org.bson.Document
+import org.junit.jupiter.api.AfterAll
+import org.junit.jupiter.api.AfterEach
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.BeforeAll
+import org.junit.jupiter.api.DisplayName
+import org.junit.jupiter.api.Test
+
+class SmokeTests {
+
+    @AfterEach
+    fun afterEach() {
+        database?.drop()
+    }
+
+    @Test
+    @DisplayName("distinct and return nulls")
+    fun testDistinctNullable() {
+        collection!!.insertMany(
+            listOf(
+                Document.parse("{_id: 1, a: 0}"),
+                Document.parse("{_id: 2, a: 1}"),
+                Document.parse("{_id: 3, a: 0}"),
+                Document.parse("{_id: 4, a: null}")))
+
+        val actual = collection!!.distinct<Int?>("a").toList().toSet()
+        assertEquals(setOf(null, 0, 1), actual)
+    }
+
+    @Test
+    @DisplayName("mapping can return nulls")
+    fun testMongoIterableMap() {
+        collection!!.insertMany(
+            listOf(
+                Document.parse("{_id: 1, a: 0}"),
+                Document.parse("{_id: 2, a: 1}"),
+                Document.parse("{_id: 3, a: 0}"),
+                Document.parse("{_id: 4, a: null}")))
+
+        val actual = collection!!.find().map { it["a"] }.toList()
+        assertContentEquals(listOf(0, 1, 0, null), actual)
+    }
+
+    companion object {
+
+        private var mongoClient: MongoClient? = null
+        private var database: MongoDatabase? = null
+        private var collection: MongoCollection<Document>? = null
+
+        @BeforeAll
+        @JvmStatic
+        internal fun beforeAll() {
+            mongoClient = MongoClient.create(getMongoClientSettings())
+            database = mongoClient?.getDatabase(getDefaultDatabaseName())
+            database?.drop()
+            collection = database?.getCollection("SmokeTests")
+        }
+
+        @AfterAll
+        @JvmStatic
+        internal fun afterAll() {
+            collection = null
+            database?.drop()
+            database = null
+            mongoClient?.close()
+            mongoClient = null
+        }
+    }
+}

driver-kotlin-sync/src/main/kotlin/com/mongodb/kotlin/client/DistinctIterable.kt

@@ -27,7 +27,7 @@ import org.bson.conversions.Bson
  * @param T The type of the result.
  * @see [Distinct command](https://www.mongodb.com/docs/manual/reference/command/distinct/)
  */
-public class DistinctIterable<T : Any>(private val wrapped: JDistinctIterable<T>) : MongoIterable<T>(wrapped) {
+public class DistinctIterable<T : Any?>(private val wrapped: JDistinctIterable<T>) : MongoIterable<T>(wrapped) {
     /**
      * Sets the number of documents to return per batch.
      *

driver-kotlin-sync/src/main/kotlin/com/mongodb/kotlin/client/MongoCollection.kt

@@ -219,7 +219,7 @@ public class MongoCollection<T : Any>(private val wrapped: JMongoCollection<T>)
      * @return an iterable of distinct values
      * @see [Distinct command](https://www.mongodb.com/docs/manual/reference/command/distinct/)
      */
-    public fun <R : Any> distinct(
+    public fun <R : Any?> distinct(
         fieldName: String,
         filter: Bson = BsonDocument(),
         resultClass: Class<R>
@@ -236,7 +236,7 @@ public class MongoCollection<T : Any>(private val wrapped: JMongoCollection<T>)
      * @return an iterable of distinct values
      * @see [Distinct command](https://www.mongodb.com/docs/manual/reference/command/distinct/)
      */
-    public fun <R : Any> distinct(
+    public fun <R : Any?> distinct(
         clientSession: ClientSession,
         fieldName: String,
         filter: Bson = BsonDocument(),
@@ -252,7 +252,7 @@ public class MongoCollection<T : Any>(private val wrapped: JMongoCollection<T>)
      * @return an iterable of distinct values
      * @see [Distinct command](https://www.mongodb.com/docs/manual/reference/command/distinct/)
      */
-    public inline fun <reified R : Any> distinct(
+    public inline fun <reified R : Any?> distinct(
         fieldName: String,
         filter: Bson = BsonDocument()
     ): DistinctIterable<R> = distinct(fieldName, filter, R::class.java)
@@ -267,7 +267,7 @@ public class MongoCollection<T : Any>(private val wrapped: JMongoCollection<T>)
      * @return an iterable of distinct values
      * @see [Distinct command](https://www.mongodb.com/docs/manual/reference/command/distinct/)
      */
-    public inline fun <reified R : Any> distinct(
+    public inline fun <reified R : Any?> distinct(
         clientSession: ClientSession,
         fieldName: String,
         filter: Bson = BsonDocument()

driver-kotlin-sync/src/main/kotlin/com/mongodb/kotlin/client/MongoCursor.kt

@@ -36,7 +36,7 @@ import org.bson.BsonDocument
  *
  * @param T The type of documents the cursor contains
  */
-public sealed interface MongoCursor<T : Any> : Iterator<T>, Closeable {
+public sealed interface MongoCursor<T : Any?> : Iterator<T>, Closeable {
 
     /**
      * Gets the number of results available locally without blocking, which may be 0.
@@ -90,7 +90,7 @@ public sealed interface MongoChangeStreamCursor<T : Any> : MongoCursor<T> {
     public val resumeToken: BsonDocument?
 }
 
-internal class MongoCursorImpl<T : Any>(private val wrapped: JMongoCursor<T>) : MongoCursor<T> {
+internal class MongoCursorImpl<T : Any?>(private val wrapped: JMongoCursor<T>) : MongoCursor<T> {
 
     override fun hasNext(): Boolean = wrapped.hasNext()
 

driver-kotlin-sync/src/main/kotlin/com/mongodb/kotlin/client/MongoIterable.kt

@@ -23,7 +23,7 @@ import com.mongodb.client.MongoIterable as JMongoIterable
  *
  * @param T The type that this iterable will decode documents to.
  */
-public open class MongoIterable<T : Any>(private val delegate: JMongoIterable<T>) {
+public open class MongoIterable<T : Any?>(private val delegate: JMongoIterable<T>) {
 
     /**
      * Returns a cursor used for iterating over elements of type `T. The cursor is primarily used for change streams.
@@ -71,7 +71,7 @@ public open class MongoIterable<T : Any>(private val delegate: JMongoIterable<T>
      * @param transform a function that maps from the source to the target document type
      * @return an iterable which maps T to U
      */
-    public fun <R : Any> map(transform: (T) -> R): MongoIterable<R> = MongoIterable(delegate.map(transform))
+    public fun <R : Any?> map(transform: (T) -> R): MongoIterable<R> = MongoIterable(delegate.map(transform))
 
     /** Performs the given [action] on each element and safely closes the cursor. */
     public fun forEach(action: (T) -> Unit): Unit = use { it.forEach(action) }