From ab76464f4ee06e320c68e57e74e8871e8b9ffbf6 Mon Sep 17 00:00:00 2001
From: "Vadim.Mishenev" <vad-mishenev@yandex.ru>
Date: Fri, 18 Oct 2024 22:51:28 +0300
Subject: [PATCH 1/2] Fix merging expect-actual declarations

---
 .../DefaultDocumentableMerger.kt              |  4 +-
 .../kotlin/expectActuals/ExpectActualsTest.kt | 55 +++++++++++++++++++
 2 files changed, 58 insertions(+), 1 deletion(-)

diff --git a/dokka-subprojects/core/src/main/kotlin/org/jetbrains/dokka/transformers/documentation/DefaultDocumentableMerger.kt b/dokka-subprojects/core/src/main/kotlin/org/jetbrains/dokka/transformers/documentation/DefaultDocumentableMerger.kt
index 9de2c2b1a4..b9956f8fa4 100644
--- a/dokka-subprojects/core/src/main/kotlin/org/jetbrains/dokka/transformers/documentation/DefaultDocumentableMerger.kt
+++ b/dokka-subprojects/core/src/main/kotlin/org/jetbrains/dokka/transformers/documentation/DefaultDocumentableMerger.kt
@@ -116,9 +116,11 @@ public class DefaultDocumentableMerger(context: DokkaContext) : DocumentableMerg
                 listOf(actuals to actuals.flatMap { it.sourceSets }.toSet())
             } else expects.map { expect ->
                 val actualsForGivenExpect = actuals.filter { actual ->
-                    dependencyInfo[actual.sourceSets.single()]
+                    actual.sourceSets.all {
+                        dependencyInfo[it]
                         ?.contains(expect.expectPresentInSet!!)
                         ?: throw IllegalStateException("Cannot resolve expect/actual relation for ${actual.name}")
+                    }
                 }
                 (listOf(expect) + actualsForGivenExpect) to actualsForGivenExpect.flatMap { it.sourceSets }.toSet()
             }
diff --git a/dokka-subprojects/plugin-base/src/test/kotlin/expectActuals/ExpectActualsTest.kt b/dokka-subprojects/plugin-base/src/test/kotlin/expectActuals/ExpectActualsTest.kt
index e7f535aa49..248f6feb7f 100644
--- a/dokka-subprojects/plugin-base/src/test/kotlin/expectActuals/ExpectActualsTest.kt
+++ b/dokka-subprojects/plugin-base/src/test/kotlin/expectActuals/ExpectActualsTest.kt
@@ -4,6 +4,7 @@
 
 package expectActuals
 
+import org.jetbrains.dokka.DokkaSourceSetID
 import org.jetbrains.dokka.base.testApi.testRunner.BaseAbstractTest
 import org.jetbrains.dokka.model.withDescendants
 import org.jetbrains.dokka.pages.ClasslikePageNode
@@ -380,4 +381,58 @@ class ExpectActualsTest : BaseAbstractTest() {
             )
         }
     }
+
+
+    @Test
+    fun `should work with the reversed order of source sets #3798`() {
+        val configuration = dokkaConfiguration {
+            sourceSets {
+                val commonId = DokkaSourceSetID("root", "common")
+                sourceSet {
+                    sourceRoots = listOf("src/jvm/")
+                    analysisPlatform = "jvm"
+                    name = "jvm"
+                    displayName = "jvm"
+                    dependentSourceSets = setOf(commonId)
+                }
+                sourceSet {
+                    sourceRoots = listOf("src/native/")
+                    analysisPlatform = "native"
+                    name = "native"
+                    displayName = "native"
+                    dependentSourceSets = setOf(commonId)
+                }
+                sourceSet {
+                    sourceRoots = listOf("src/common/")
+                    analysisPlatform = "common"
+                    name = "common"
+                    displayName = "common"
+                }
+            }
+        }
+
+        testInline(
+            """
+        /src/common/test.kt
+        expect fun shared()
+        
+        /src/native/test.kt
+        actual fun shared(){}
+        
+        /src/jvm/test.kt
+        actual fun shared(){}
+        """.trimMargin(), configuration
+        ) {
+            documentablesTransformationStage = { module ->
+                val function = module.packages.single().functions.single { it.name == "shared" }
+                assertTrue(function.isExpectActual)
+                assertEquals(
+                    "common", function.expectPresentInSet?.sourceSetID?.sourceSetName
+                )
+                assertEquals(
+                    setOf("common", "jvm", "native"), function.sourceSets.map { it.sourceSetID.sourceSetName }.toSet()
+                )
+            }
+        }
+    }
 }

From 7e5fa295fedadb3d6b20854d9317fd68d53b640a Mon Sep 17 00:00:00 2001
From: "Vadim.Mishenev" <vad-mishenev@yandex.ru>
Date: Mon, 21 Oct 2024 10:52:44 +0300
Subject: [PATCH 2/2] Add comment

---
 .../transformers/documentation/DefaultDocumentableMerger.kt      | 1 +
 1 file changed, 1 insertion(+)

diff --git a/dokka-subprojects/core/src/main/kotlin/org/jetbrains/dokka/transformers/documentation/DefaultDocumentableMerger.kt b/dokka-subprojects/core/src/main/kotlin/org/jetbrains/dokka/transformers/documentation/DefaultDocumentableMerger.kt
index b9956f8fa4..c7565be2c3 100644
--- a/dokka-subprojects/core/src/main/kotlin/org/jetbrains/dokka/transformers/documentation/DefaultDocumentableMerger.kt
+++ b/dokka-subprojects/core/src/main/kotlin/org/jetbrains/dokka/transformers/documentation/DefaultDocumentableMerger.kt
@@ -116,6 +116,7 @@ public class DefaultDocumentableMerger(context: DokkaContext) : DocumentableMerg
                 listOf(actuals to actuals.flatMap { it.sourceSets }.toSet())
             } else expects.map { expect ->
                 val actualsForGivenExpect = actuals.filter { actual ->
+                    // [actual.sourceSets] can already be partially merged and contain more than one source set
                     actual.sourceSets.all {
                         dependencyInfo[it]
                         ?.contains(expect.expectPresentInSet!!)