Fix Kotlin Metadata unique_name value so that it is actually unique

build-logic/src/main/kotlin/publication.gradle.kts

@@ -29,3 +29,71 @@ tasks.withType<AbstractArchiveTask>().configureEach {
     isPreserveFileTimestamps = false
     isReproducibleFileOrder = true
 }
+
+// Hooks into project's metadata compilation task to ensure that the `unique_name`
+// attribute is properly prefixed with the project group name, instead of just the
+// `{module name}_sourceSet`
+//
+// Requires that `GROUP` is set in gradle.properties, or that project.group is set.
+//
+// Enable debug output by adding the following to root-project gradle.properties:
+//
+//     kotlin.mpp.fixMetadataUniqueNameDebug=true
+//
+// https://youtrack.jetbrains.com/issue/KT-66568/w-KLIB-resolver-The-same-uniquename...-found-in-more-than-one-library
+tasks.all {
+    if (!name.startsWith("compile")) return@all
+    if (!name.endsWith("MainKotlinMetadata")) return@all
+
+    // Take gradle.properties `GROUP`, otherwise use `project.group`
+    val groupName = properties["GROUP"]
+        ?.toString()
+        ?.ifBlank { null }
+        ?: project.group.toString()
+            .ifBlank { null }
+
+    if (groupName.isNullOrBlank()) {
+        throw GradleException("group cannot be null or blank")
+    }
+
+    doLast {
+        outputs.files.files.forEach out@ { output ->
+            val manifests = output.walkTopDown().mapNotNull { file ->
+                file.takeIf { it.name == "manifest" }
+            }
+            manifests.forEach { manifest ->
+                val lines = manifest.readLines()
+                val map = LinkedHashMap<String, String>(lines.size, 1.0f)
+
+                for (line in lines) {
+                    val i = line.indexOf('=')
+                    if (i == -1) continue
+                    map[line.substring(0, i)] = line.substring(i + 1)
+                }
+
+                val current = map["unique_name"] ?: return@forEach
+                if (current.startsWith(groupName)) return@forEach
+                val new = "$groupName\\:$current"
+
+                if (properties["kotlin.mpp.fixMetadataUniqueNameDebug"] == "true") {
+                    println("""
+                        Misconfigured unique_name metadata attribute
+                        for $manifest
+                        Changing from '$current' to '$new'
+                    """.trimIndent())
+                }
+
+                map["unique_name"] = new
+
+                manifest.bufferedWriter().use { writer ->
+                    map.entries.forEach { (key, value) ->
+                        writer.write(key)
+                        writer.write("=")
+                        writer.write(value)
+                        writer.newLine()
+                    }
+                }
+            }
+        }
+    }
+}