Ensure custom KProperty include the name in the hashcode (mongodb#1710)

The `pathCache` utilised the string representation of the KProperty instance.
The custom implementations didn't include the calculated `path` value, this can
lead to naming collisions in the `pathCache` key.

This commit adds `hashCode` and `equals` methods to ensure the `name` value is included
in our custom implementations of `KProperty1`. Finally, the cache key now uses the `hashCode` 
for the cacheKey.

JAVA-5868

Author: rozza

driver-kotlin-extensions/src/main/kotlin/com/mongodb/kotlin/client/model/Properties.kt

@@ -32,7 +32,7 @@ import kotlin.reflect.jvm.javaField
 import org.bson.codecs.pojo.annotations.BsonId
 import org.bson.codecs.pojo.annotations.BsonProperty
 
-private val pathCache: MutableMap<String, String> by lazySoft { ConcurrentHashMap<String, String>() }
+private val pathCache: MutableMap<Int, String> by lazySoft { ConcurrentHashMap<Int, String>() }
 
 /** Returns a composed property. For example Friend::address / Address::postalCode = "address.postalCode". */
 public operator fun <T0, T1, T2> KProperty1<T0, T1?>.div(p2: KProperty1<T1, T2?>): KProperty1<T0, T2?> =
@@ -71,8 +71,7 @@ public fun <T> KProperty<T>.path(): String {
     return if (this is KPropertyPath<*, T>) {
         this.name
     } else {
-        pathCache.computeIfAbsent(this.toString()) {
-
+        pathCache.computeIfAbsent(hashCode()) {
             // Check serial name - Note kotlinx.serialization.SerialName may not be on the class
             // path
             val serialName =

driver-kotlin-extensions/src/main/kotlin/com/mongodb/kotlin/client/property/KPropertyPath.kt

@@ -20,6 +20,7 @@ package com.mongodb.kotlin.client.property
 
 import com.mongodb.annotations.Sealed
 import com.mongodb.kotlin.client.model.path
+import java.util.Objects
 import kotlin.reflect.KParameter
 import kotlin.reflect.KProperty1
 import kotlin.reflect.KType
@@ -84,6 +85,15 @@ public open class KPropertyPath<T, R>(
     override fun callBy(args: Map<KParameter, Any?>): R = unSupportedOperation()
     override fun get(receiver: T): R = unSupportedOperation()
     override fun getDelegate(receiver: T): Any? = unSupportedOperation()
+    override fun hashCode(): Int = Objects.hash(previous, property, name)
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (javaClass != other?.javaClass) return false
+        other as KPropertyPath<*, *>
+        return Objects.equals(previous, other.previous) &&
+            Objects.equals(property, other.property) &&
+            Objects.equals(name, other.name)
+    }
 
     public companion object {
 
@@ -121,6 +131,13 @@ public open class KPropertyPath<T, R>(
             override fun get(receiver: T): R = unSupportedOperation()
             override fun getDelegate(receiver: T): Any? = unSupportedOperation()
             override fun invoke(p1: T): R = unSupportedOperation()
+            override fun hashCode(): Int = Objects.hash(previous, name)
+            override fun equals(other: Any?): Boolean {
+                if (this === other) return true
+                if (javaClass != other?.javaClass) return false
+                other as CustomProperty<*, *>
+                return Objects.equals(previous, other.previous) && Objects.equals(name, other.name)
+            }
         }
 
         /** Provides "fake" property with custom name. */

driver-kotlin-extensions/src/test/kotlin/com/mongodb/kotlin/client/model/KPropertiesTest.kt

@@ -139,4 +139,20 @@ class KPropertiesTest {
         assertThrows<UnsupportedOperationException> { property.get(restaurant) }
         assertThrows<UnsupportedOperationException> { property.getDelegate(restaurant) }
     }
+
+    @Test
+    fun testNoCacheCollisions() {
+        for (i in 1.rangeTo(25_000)) {
+            assertEquals("reviews.$i", Restaurant::reviews.pos(i).path())
+            assertEquals("reviews.$[identifier$i]", Restaurant::reviews.filteredPosOp("identifier$i").path())
+            assertEquals("localeMap.$i", Restaurant::localeMap.keyProjection(i).path())
+
+            val x = i / 2
+            assertEquals(
+                "reviews.$[identifier$x].rating",
+                (Restaurant::reviews.filteredPosOp("identifier$x") / Review::score).path())
+            assertEquals("reviews.$x.rating", (Restaurant::reviews.pos(x) / Review::score).path())
+            assertEquals("localeMap.$x.rating", (Restaurant::localeMap.keyProjection(x) / Review::score).path())
+        }
+    }
 }