workaround bugged Gradle attributes

modules/dokkatoo-plugin/src/main/kotlin/dependencies/DokkatooAttribute.kt

@@ -16,25 +16,34 @@ interface DokkatooAttribute {
 
   /** HTML, Markdown, etc. */
   @DokkatooInternalApi
-  interface Format : Named
+  @JvmInline
+  value class Format(private val named: String) : Named {
+    override fun getName(): String = named
+  }
 
   /** Generated output, or subproject classpath, or included files, etc */
   @DokkatooInternalApi
-  interface ModuleComponent : Named
+  @JvmInline
+  value class ModuleComponent(private val named: String) : Named {
+    override fun getName(): String = named
+  }
 
   /** A classpath, e.g. for Dokka Plugins or the Dokka Generator. */
   @DokkatooInternalApi
-  interface Classpath : Named
+  @JvmInline
+  value class Classpath(private val named: String) : Named {
+    override fun getName(): String = named
+  }
 
   @DokkatooInternalApi
   companion object {
-    val DokkatooFormatAttribute: Attribute<Format> =
+    val DokkatooFormatAttribute: Attribute<String> =
       Attribute("dev.adamko.dokkatoo.format")
 
-    val DokkatooModuleComponentAttribute: Attribute<ModuleComponent> =
+    val DokkatooModuleComponentAttribute: Attribute<String> =
       Attribute("dev.adamko.dokkatoo.module-component")
 
-    val DokkatooClasspathAttribute: Attribute<Classpath> =
+    val DokkatooClasspathAttribute: Attribute<String> =
       Attribute("dev.adamko.dokkatoo.classpath")
   }
 }

modules/dokkatoo-plugin/src/main/kotlin/dependencies/FormatDependenciesManager.kt

@@ -48,7 +48,6 @@ class FormatDependenciesManager(
   internal val formatAttributes: FormatAttributes =
     FormatAttributes(
       formatName = formatName,
-      objects = objects,
     )
 
   init {
@@ -94,8 +93,8 @@ class FormatDependenciesManager(
       isTransitive = false
       attributes {
         jvmJar()
-        attribute(DokkatooFormatAttribute, formatAttributes.format)
-        attribute(DokkatooClasspathAttribute, baseAttributes.dokkaPlugins)
+        attribute(DokkatooFormatAttribute, formatAttributes.format.name)
+        attribute(DokkatooClasspathAttribute, baseAttributes.dokkaPlugins.name)
       }
     }
   //endregion
@@ -117,8 +116,8 @@ class FormatDependenciesManager(
       extendsFrom(dokkaPublicationPluginClasspath.get())
       attributes {
         jvmJar()
-        attribute(DokkatooFormatAttribute, formatAttributes.format)
-        attribute(DokkatooClasspathAttribute, baseAttributes.dokkaPublicationPlugins)
+        attribute(DokkatooFormatAttribute, formatAttributes.format.name)
+        attribute(DokkatooClasspathAttribute, baseAttributes.dokkaPublicationPlugins.name)
       }
     }
 
@@ -137,8 +136,8 @@ class FormatDependenciesManager(
       extendsFrom(dokkaPublicationPluginClasspathApiOnly.get())
       attributes {
         jvmJar()
-        attribute(DokkatooFormatAttribute, formatAttributes.format)
-        attribute(DokkatooClasspathAttribute, baseAttributes.dokkaPublicationPlugins)
+        attribute(DokkatooFormatAttribute, formatAttributes.format.name)
+        attribute(DokkatooClasspathAttribute, baseAttributes.dokkaPublicationPlugins.name)
       }
     }
   }
@@ -186,8 +185,8 @@ class FormatDependenciesManager(
 
       attributes {
         jvmJar()
-        attribute(DokkatooFormatAttribute, formatAttributes.format)
-        attribute(DokkatooClasspathAttribute, baseAttributes.dokkaGenerator)
+        attribute(DokkatooFormatAttribute, formatAttributes.format.name)
+        attribute(DokkatooClasspathAttribute, baseAttributes.dokkaGenerator.name)
       }
     }
   //endregion

modules/dokkatoo-plugin/src/main/kotlin/dependencies/ModuleComponentDependencies.kt

@@ -33,8 +33,8 @@ class ModuleComponentDependencies(
       extendsFrom(declaredDependencies)
       attributes {
         attribute(USAGE_ATTRIBUTE, baseAttributes.dokkatooUsage)
-        attribute(DokkatooFormatAttribute, formatAttributes.format)
-        attribute(DokkatooModuleComponentAttribute, component)
+        attribute(DokkatooFormatAttribute, formatAttributes.format.name)
+        attribute(DokkatooModuleComponentAttribute, component.name)
       }
     }
 
@@ -46,8 +46,8 @@ class ModuleComponentDependencies(
       extendsFrom(declaredDependencies)
       attributes {
         attribute(USAGE_ATTRIBUTE, baseAttributes.dokkatooUsage)
-        attribute(DokkatooFormatAttribute, formatAttributes.format)
-        attribute(DokkatooModuleComponentAttribute, component)
+        attribute(DokkatooFormatAttribute, formatAttributes.format.name)
+        attribute(DokkatooModuleComponentAttribute, component.name)
       }
     }
 
@@ -83,8 +83,8 @@ class ModuleComponentDependencies(
         withVariantReselection()
         attributes {
           attribute(USAGE_ATTRIBUTE, usage)
-          attribute(DokkatooFormatAttribute, formatAttributes.format)
-          attribute(DokkatooModuleComponentAttribute, component)
+          attribute(DokkatooFormatAttribute, formatAttributes.format.name)
+          attribute(DokkatooModuleComponentAttribute, component.name)
         }
         lenient(true)
       }
@@ -98,23 +98,23 @@ class ModuleComponentDependencies(
           .filter { artifact ->
             val variantAttributes = artifact.variant.attributes
             when {
-              artifact.variant.attributes[USAGE_ATTRIBUTE]?.name != baseAttributes.dokkatooUsage.name -> {
-                logger.info("[${incomingName}] ignoring artifact $artifact - USAGE_ATTRIBUTE != ${baseAttributes.dokkatooUsage} | attributes:${variantAttributes.toMap()}")
+              variantAttributes[USAGE_ATTRIBUTE]?.name != baseAttributes.dokkatooUsage.name -> {
+                logger.info("[${incomingName}] ignoring artifact $artifact - USAGE_ATTRIBUTE != ${baseAttributes.dokkatooUsage} | attributes:${variantAttributes.toDebugString()}")
                 false
               }
 
-              variantAttributes[DokkatooFormatAttribute]?.name != formatAttributes.format.name        -> {
-                logger.info("[${incomingName}] ignoring artifact $artifact - DokkatooFormatAttribute != ${formatAttributes.format} | attributes:${variantAttributes.toMap()}")
+              variantAttributes[DokkatooFormatAttribute] != formatAttributes.format.name    -> {
+                logger.info("[${incomingName}] ignoring artifact $artifact - DokkatooFormatAttribute != ${formatAttributes.format} | attributes:${variantAttributes.toDebugString()}")
                 false
               }
 
-              variantAttributes[DokkatooModuleComponentAttribute]?.name != component.name             -> {
-                logger.info("[${incomingName}] ignoring artifact $artifact - DokkatooModuleComponentAttribute != $component | attributes:${variantAttributes.toMap()}")
+              variantAttributes[DokkatooModuleComponentAttribute] != component.name         -> {
+                logger.info("[${incomingName}] ignoring artifact $artifact - DokkatooModuleComponentAttribute != $component | attributes:${variantAttributes.toDebugString()}")
                 false
               }
 
-              else                                                                                    -> {
-                logger.info("[${incomingName}] found valid artifact $artifact | attributes:${variantAttributes.toMap()}")
+              else                                                                          -> {
+                logger.info("[${incomingName}] found valid artifact $artifact | attributes:${variantAttributes.toDebugString()}")
                 true
               }
             }

modules/dokkatoo-plugin/src/main/kotlin/dependencies/attributeValues.kt

@@ -15,21 +15,26 @@ class BaseAttributes(
   objects: ObjectFactory,
 ) {
   val dokkatooUsage: Usage = objects.named("dev.adamko.dokkatoo")
-  val dokkaPlugins: DokkatooAttribute.Classpath = objects.named("dokka-plugins")
+
+  val dokkaPlugins: DokkatooAttribute.Classpath =
+    DokkatooAttribute.Classpath("dokka-plugins")
+
   val dokkaPublicationPlugins: DokkatooAttribute.Classpath =
-    objects.named("dokka-publication-plugins")
-  val dokkaGenerator: DokkatooAttribute.Classpath = objects.named("dokka-generator")
+    DokkatooAttribute.Classpath("dokka-publication-plugins")
+
+  val dokkaGenerator: DokkatooAttribute.Classpath =
+    DokkatooAttribute.Classpath("dokka-generator")
 }
 
 
 /** [Attribute] values for a specific Dokka format. */
 @DokkatooInternalApi
 class FormatAttributes(
   formatName: String,
-  objects: ObjectFactory,
 ) {
-  val format: DokkatooAttribute.Format = objects.named(formatName)
+  val format: DokkatooAttribute.Format =
+    DokkatooAttribute.Format(formatName)
 
   val moduleOutputDirectories: DokkatooAttribute.ModuleComponent =
-    objects.named("ModuleOutputDirectories")
+    DokkatooAttribute.ModuleComponent("ModuleOutputDirectories")
 }

modules/dokkatoo-plugin/src/main/kotlin/formats/DokkatooFormatPlugin.kt

@@ -165,13 +165,13 @@ abstract class DokkatooFormatPlugin(
       dokkatooExtension.versions.jetbrainsDokka.map { version -> create("org.jetbrains.dokka:$module:$version") }
 
     private fun AttributeContainer.dokkaPluginsClasspath() {
-      attribute(DokkatooFormatAttribute, formatDependencies.formatAttributes.format)
-      attribute(DokkatooClasspathAttribute, formatDependencies.baseAttributes.dokkaPlugins)
+      attribute(DokkatooFormatAttribute, formatDependencies.formatAttributes.format.name)
+      attribute(DokkatooClasspathAttribute, formatDependencies.baseAttributes.dokkaPlugins.name)
     }
 
     private fun AttributeContainer.dokkaGeneratorClasspath() {
-      attribute(DokkatooFormatAttribute, formatDependencies.formatAttributes.format)
-      attribute(DokkatooClasspathAttribute, formatDependencies.baseAttributes.dokkaGenerator)
+      attribute(DokkatooFormatAttribute, formatDependencies.formatAttributes.format.name)
+      attribute(DokkatooClasspathAttribute, formatDependencies.baseAttributes.dokkaGenerator.name)
     }
 
     /** Add a dependency to the Dokka plugins classpath */

modules/dokkatoo-plugin/src/main/kotlin/internal/gradleUtils.kt

@@ -237,16 +237,33 @@ internal fun ObjectFactory.dokkaPluginParametersContainer(): DokkaPluginParamete
 
 
 /**
- * Creates a new attribute of the given name with the given type.
+ * Creates a new [Attribute] of the given name with the given type [T].
  *
  * @see Attribute.of
  */
+@Deprecated(
+  "Typed attributes are broken - use String attributes instead. https://github.com/adamko-dev/dokkatoo/issues/214",
+  ReplaceWith("dev.adamko.dokkatoo.internal.Attribute(name)"),
+)
+@JvmName("TypedAttribute")
 internal inline fun <reified T> Attribute(
   name: String
 ): Attribute<T> =
   Attribute.of(name, T::class.java)
 
 
+/**
+ * Creates a new [Attribute] of the given name with a type of [String].
+ *
+ * @see Attribute.of
+ */
+@JvmName("StringAttribute")
+internal fun Attribute(
+  name: String
+): Attribute<String> =
+  Attribute.of(name, String::class.java)
+
+
 internal val ArtifactTypeAttribute: Attribute<String> = Attribute("artifactType")
 
 
@@ -262,14 +279,59 @@ internal fun AttributeContainer.toMap(): Map<Attribute<*>, Any?> =
   keySet().associateWith { getAttribute(it) }
 
 
+internal fun AttributeContainer.toDebugString(): String =
+  toMap().entries.joinToString { (k, v) -> "$k[name:${k.name}, type:${k.type}, type.hc:${k.type.hashCode()}]=$v" }
+
+
 /**
  * Get an [Attribute] from an [AttributeContainer].
  *
  * (Nicer Kotlin accessor function).
  */
-internal operator fun <T : Any> AttributeContainer.get(key: Attribute<T>): T? =
-  getAttribute(key)
+internal operator fun <T : Any> AttributeContainer.get(key: Attribute<T>): T? {
+  // first, try the official way
+  val value = getAttribute(key)
+  if (value != null) {
+    return value
+  }
 
+  // Failed to get attribute using official method, which might have been caused by a Gradle bug
+  // https://github.com/gradle/gradle/issues/28695
+  // Attempting to check...
 
-internal infix fun <T> Attribute<T>?.eq(other: Attribute<T>) =
-  this?.name == other.name
+  // Quickly check that any attribute has the same name.
+  // (There's no point in checking further if no names match.)
+  if (keySet().none { it.name == key.name }) {
+    return null
+  }
+
+  val actualKey = keySet()
+    .firstOrNull { candidate -> candidate.matchesTypeOf(key) }
+    ?: return null
+
+  error(
+    """
+      Gradle failed to fetch attribute from AttributeContainer, even though the attribute is present.
+      Please report this error to Gradle https://github.com/gradle/gradle/issues/28695
+        Requested attribute: $key ${key.type} ${key.type.hashCode()}
+        Actual attribute: $actualKey ${actualKey.type} ${actualKey.type.hashCode()}
+        All attributes: ${toDebugString()}
+        Gradle Version: $CurrentGradleVersion
+    """.trimIndent()
+  )
+}
+
+/** Leniently check if [Attribute.type]s are equal, avoiding [Class.hashCode] classloader differences. */
+private fun Attribute<*>.matchesTypeOf(other: Attribute<*>): Boolean {
+  val thisTypeId = this.typeId() ?: false
+  val otherTypeId = other.typeId() ?: false
+  return thisTypeId == otherTypeId
+}
+
+/**
+ * An ID for [Attribute.type] that is stable across different classloaders.
+ *
+ * Workaround for https://github.com/gradle/gradle/issues/28695.
+ */
+private fun Attribute<*>.typeId(): String? =
+  type.toString().ifBlank { null }