From 38ab2dca0358d2b291d7646848f4150be89dd0a9 Mon Sep 17 00:00:00 2001
From: Silvio Giebl <gieblsilvio@outlook.com>
Date: Sun, 3 Nov 2024 23:38:21 +0100
Subject: [PATCH] Improve resolution code

---
 .../internal/dsl/OciImageDependenciesImpl.kt  | 12 ++-----
 .../resolution/OciImageSpecResolution.kt      | 34 ++++++++++++++-----
 2 files changed, 29 insertions(+), 17 deletions(-)

diff --git a/src/main/kotlin/io/github/sgtsilvio/gradle/oci/internal/dsl/OciImageDependenciesImpl.kt b/src/main/kotlin/io/github/sgtsilvio/gradle/oci/internal/dsl/OciImageDependenciesImpl.kt
index 2ed6bffb..6df95dc4 100644
--- a/src/main/kotlin/io/github/sgtsilvio/gradle/oci/internal/dsl/OciImageDependenciesImpl.kt
+++ b/src/main/kotlin/io/github/sgtsilvio/gradle/oci/internal/dsl/OciImageDependenciesImpl.kt
@@ -65,15 +65,9 @@ internal abstract class OciImageDependenciesImpl @Inject constructor(
                 throw e
             }
             val platformSelector = platformSelectorProvider.orNull
-            val graphRootAndPlatformsList = selectPlatforms(graph, platformSelector)
-            val platformToGraphRoots = HashMap<Platform, ArrayList<OciVariantGraphRoot>>()
-            for ((graphRoot, platforms) in graphRootAndPlatformsList) {
-                for (platform in platforms) {
-                    platformToGraphRoots.getOrPut(platform) { ArrayList() } += graphRoot
-                }
-            }
+            val selectedPlatformsGraph = graph.selectPlatforms(platformSelector)
             val allDependencies = allDependencies.value
-            val platformToConfiguration = platformToGraphRoots.mapValues { (platform, graphRoots) ->
+            val platformToConfiguration = selectedPlatformsGraph.groupByPlatform().mapValues { (platform, graphRoots) ->
                 val platformConfigurationName =
                     "${indexConfiguration.name}@$platform" + if (platformSelector == null) "" else "($platformSelector)"
                 platformConfigurations.getOrPut(platformConfigurationName) {
@@ -112,7 +106,7 @@ internal abstract class OciImageDependenciesImpl @Inject constructor(
                 }
             }
             val imageInputs = ArrayList<OciImagesTask.ImageInput>()
-            for ((graphRoot, platforms) in graphRootAndPlatformsList) {
+            for ((graphRoot, platforms) in selectedPlatformsGraph) {
                 for (platform in platforms) {
                     imageInputs += variantSelectorsToImageInput[Pair(platform, graphRoot.variantSelectors)]
                         ?: throw IllegalStateException() // TODO message
diff --git a/src/main/kotlin/io/github/sgtsilvio/gradle/oci/internal/resolution/OciImageSpecResolution.kt b/src/main/kotlin/io/github/sgtsilvio/gradle/oci/internal/resolution/OciImageSpecResolution.kt
index 3cd0c238..ebf40f5c 100644
--- a/src/main/kotlin/io/github/sgtsilvio/gradle/oci/internal/resolution/OciImageSpecResolution.kt
+++ b/src/main/kotlin/io/github/sgtsilvio/gradle/oci/internal/resolution/OciImageSpecResolution.kt
@@ -87,16 +87,34 @@ private fun String.decodePlatforms() = split(';').mapTo(LinkedHashSet()) { it.to
 
 // TODO new file from here?
 
-internal fun selectPlatforms(
-    graph: List<OciVariantGraphRoot>,
+internal fun List<OciVariantGraphRoot>.selectPlatforms(
     platformSelector: PlatformSelector?,
-): List<Pair<OciVariantGraphRoot, Set<Platform>>> = graph.map { graphRoot ->
-    val rootNode = graphRoot.node
-    val platforms = platformSelector?.select(rootNode.supportedPlatforms) ?: rootNode.supportedPlatforms.set
-    if (platforms.isEmpty()) { // TODO defer exception, empty set is failed
-        throw IllegalStateException("no platforms can be selected for variant ${rootNode.variant} (supported platforms: ${rootNode.supportedPlatforms}, platform selector: $platformSelector)")
+): List<Pair<OciVariantGraphRoot, Set<Platform>>> {
+    var hasEmptySelection = false
+    val selectedPlatformsGraph = map { graphRoot ->
+        val supportedPlatforms = graphRoot.node.supportedPlatforms
+        val platforms = platformSelector?.select(supportedPlatforms) ?: supportedPlatforms.set
+        if (platforms.isEmpty()) {
+            hasEmptySelection = true
+        }
+        Pair(graphRoot, platforms)
+    }
+    if (hasEmptySelection) {
+        val errorMessage = selectedPlatformsGraph.filter { (_, platforms) -> platforms.isEmpty() }
+            .joinToString("\n") { (graphRoot) -> "no platforms can be selected for variant ${graphRoot.node.variant} (supported platforms: ${graphRoot.node.supportedPlatforms}, platform selector: $platformSelector)" }
+        throw IllegalStateException(errorMessage)
+    }
+    return selectedPlatformsGraph
+}
+
+internal fun List<Pair<OciVariantGraphRoot, Set<Platform>>>.groupByPlatform(): Map<Platform, List<OciVariantGraphRoot>> {
+    val platformToGraphRoots = HashMap<Platform, ArrayList<OciVariantGraphRoot>>()
+    for ((graphRoot, platforms) in this) {
+        for (platform in platforms) {
+            platformToGraphRoots.getOrPut(platform) { ArrayList() } += graphRoot
+        }
     }
-    Pair(graphRoot, platforms)
+    return platformToGraphRoots
 }
 
 // TODO new file from here?