Refactor and document DisplaySourceSet, deprecate SelfRepresentingSingletonSet (#3105)

* Deprecate internal API SelfRepresentingSingletonSet for removal as being harmful and unimplement it in DisplaySourceSet
* Provide no automatic migration for DisplaySourceSet, as there are no mechanisms for that. Manual migration is the replacement of 'dss' to `setOf(dss)` where applicable
* Introduce a convenience-member DefaultRenderer.buildContentNode to avoid wrapping DSS into set manually
* Document DisplaySourceSet
* Replace Iterable<DisplaySourceSet>.sourceSetIDs with more straightforward Iterable<DisplaySourceSet>.computeSourceSetIds(), refactor all the usages, save some allocations
* Start caching CompositeSourceSetID properties to avoid excessive allocations
* Update integration tests on the latest revision with Knit version where the workaround is applied

Fixes #2897

1 files changed, 5 insertions, 1 deletions

diff --git a/core/src/test/kotlin/model/CompositeSourceSetIDTest.kt b/core/src/test/kotlin/model/CompositeSourceSetIDTest.kt
index 472581e7..aa5a801d 100644
--- a/core/src/test/kotlin/model/CompositeSourceSetIDTest.kt
+++ b/core/src/test/kotlin/model/CompositeSourceSetIDTest.kt
@@ -2,7 +2,6 @@ package model
 
 import org.jetbrains.dokka.DokkaSourceSetID
 import org.jetbrains.dokka.model.CompositeSourceSetID
-import org.jetbrains.dokka.model.plus
 import kotlin.test.*
 
 class CompositeSourceSetIDTest {
@@ -65,4 +64,9 @@ class CompositeSourceSetIDTest {
             "Expected all three source sets being merged in order"
         )
     }
+
+    operator fun DokkaSourceSetID.plus(other: DokkaSourceSetID): CompositeSourceSetID {
+        return CompositeSourceSetID(listOf(this, other))
+    }
+
 }