CORDA-2825 - Fix Progress Tracker bug (#4986) (#4989)

* CORDA-2825 Fix Progress Tracker bug

CORDA-2825 Add discriminator

CORDA-2825 Fix hashcode

CORDA-2825 remove todo

CORDA-2825 more tests

* CORDA-2825 Address code review comments

(cherry picked from commit 685f94bf6659ae4a1b7589e43f518fd9420ef5ce)

core/src/main/kotlin/net/corda/core/utilities/ProgressTracker.kt

@@ -2,6 +2,7 @@ package net.corda.core.utilities
 
 import net.corda.core.DeleteForDJVM
 import net.corda.core.internal.STRUCTURAL_STEP_PREFIX
+import net.corda.core.internal.warnOnce
 import net.corda.core.serialization.CordaSerializable
 import rx.Observable
 import rx.Subscription
@@ -34,6 +35,10 @@ import java.util.*
 @DeleteForDJVM
 class ProgressTracker(vararg inputSteps: Step) {
 
+    private companion object {
+        private val log = contextLogger()
+    }
+
     @CordaSerializable
     @DeleteForDJVM
     sealed class Change(val progressTracker: ProgressTracker) {
@@ -55,6 +60,11 @@ class ProgressTracker(vararg inputSteps: Step) {
      */
     @CordaSerializable
     open class Step(open val label: String) {
+        private fun definitionLocation(): String = Exception().stackTrace.first { it.className != ProgressTracker.Step::class.java.name }.let { "${it.className}:${it.lineNumber}" }
+
+        // Required when Steps with the same name are defined in multiple places.
+        private val discriminator: String = definitionLocation()
+
         open val changes: Observable<Change> get() = Observable.empty()
         open fun childProgressTracker(): ProgressTracker? = null
         /**
@@ -63,6 +73,17 @@ class ProgressTracker(vararg inputSteps: Step) {
          * Even if empty the basic details (i.e. label) of the step will be recorded for audit purposes.
          */
         open val extraAuditData: Map<String, String> get() = emptyMap()
+
+        override fun equals(other: Any?) = when (other) {
+            is Step -> this.label == other.label && this.discriminator == other.discriminator
+            else -> false
+        }
+
+        override fun hashCode(): Int {
+            var result = label.hashCode()
+            result = 31 * result + discriminator.hashCode()
+            return result
+        }
     }
 
     // Sentinel objects. Overrides equals() to survive process restarts and serialization.
@@ -89,7 +110,12 @@ class ProgressTracker(vararg inputSteps: Step) {
     /**
      * The steps in this tracker, same as the steps passed to the constructor but with UNSTARTED and DONE inserted.
      */
-    val steps = arrayOf(UNSTARTED, STARTING, *inputSteps, DONE)
+    val steps = arrayOf(UNSTARTED, STARTING, *inputSteps, DONE).also { stepsArray ->
+        val labels = stepsArray.map { it.label }
+        if (labels.toSet().size < labels.size) {
+            log.warnOnce("Found ProgressTracker Step(s) with the same label: ${labels.groupBy { it }.filter { it.value.size > 1 }.map { it.key }}")
+        }
+    }
 
     private var _allStepsCache: List<Pair<Int, Step>> = _allSteps()
 
@@ -137,7 +163,6 @@ class ProgressTracker(vararg inputSteps: Step) {
             }
         }
 
-
     init {
         steps.forEach {
             configureChildTrackerForStep(it)

core/src/test/kotlin/net/corda/core/utilities/ProgressTrackerTest.kt

@@ -1,13 +1,25 @@
 package net.corda.core.utilities
 
+import net.corda.core.serialization.internal.checkpointDeserialize
+import net.corda.core.serialization.internal.checkpointSerialize
+import net.corda.core.utilities.ProgressTrackerTest.NonSingletonSteps.first
+import net.corda.core.utilities.ProgressTrackerTest.NonSingletonSteps.first2
+import net.corda.testing.core.internal.CheckpointSerializationEnvironmentRule
 import org.assertj.core.api.Assertions.assertThat
 import org.junit.Before
+import org.junit.Rule
 import org.junit.Test
 import java.util.*
 import kotlin.test.assertEquals
 import kotlin.test.assertFails
+import kotlin.test.assertNotEquals
 
 class ProgressTrackerTest {
+
+    @Rule
+    @JvmField
+    val testCheckpointSerialization = CheckpointSerializationEnvironmentRule()
+
     object SimpleSteps {
         object ONE : ProgressTracker.Step("one")
         object TWO : ProgressTracker.Step("two")
@@ -320,4 +332,40 @@ class ProgressTrackerTest {
     fun `cannot assign step not belonging to this progress tracker`() {
         assertFails { pt.currentStep = BabySteps.UNOS }
     }
+
+    object NonSingletonSteps {
+        val first = ProgressTracker.Step("first")
+        val second = ProgressTracker.Step("second")
+        val first2 = ProgressTracker.Step("first")
+        fun tracker() = ProgressTracker(first, second, first2)
+    }
+
+    @Test
+    fun `Serializing and deserializing a tracker maintains equality`() {
+        val step = NonSingletonSteps.first
+        val recreatedStep = step
+                .checkpointSerialize(testCheckpointSerialization.checkpointSerializationContext)
+                .checkpointDeserialize(testCheckpointSerialization.checkpointSerializationContext)
+        assertEquals(step, recreatedStep)
+    }
+
+    @Test
+    fun `can assign a recreated equal step`() {
+        val tracker = NonSingletonSteps.tracker()
+        val recreatedStep = first
+                .checkpointSerialize(testCheckpointSerialization.checkpointSerializationContext)
+                .checkpointDeserialize(testCheckpointSerialization.checkpointSerializationContext)
+        tracker.currentStep = recreatedStep
+    }
+
+    @Test
+    fun `Steps with the same label defined in different places are not equal`() {
+        val one = ProgressTracker.Step("one")
+        assertNotEquals(one, SimpleSteps.ONE)
+    }
+
+    @Test
+    fun `Steps with the same label defined in the same place are also not equal`() {
+        assertNotEquals(first, first2)
+    }
 }