Consistent alphabetical order of element groups in index and navigati…

…on (#2861)

* Sort groups of divergent elements by their key first ignoring case, then preserving it

* Add tests for sorting groups and navigation

plugins/base/src/main/kotlin/renderers/html/NavigationDataProvider.kt

@@ -6,6 +6,7 @@ import org.jetbrains.dokka.base.transformers.documentables.isDeprecated
 import org.jetbrains.dokka.base.transformers.documentables.isException
 import org.jetbrains.dokka.base.translators.documentables.DocumentableLanguage
 import org.jetbrains.dokka.base.translators.documentables.documentableLanguage
+import org.jetbrains.dokka.base.utils.canonicalAlphabeticalOrder
 import org.jetbrains.dokka.model.*
 import org.jetbrains.dokka.pages.*
 
@@ -90,14 +91,17 @@ abstract class NavigationDataProvider {
         }
     }
 
+    private val navigationNodeOrder: Comparator<NavigationNode> =
+        compareBy(canonicalAlphabeticalOrder) { it.name }
+
     private fun ContentPage.navigableChildren() =
         if (this is ClasslikePage) {
             this.navigableChildren()
         } else {
             children
                 .filterIsInstance<ContentPage>()
                 .map { visit(it) }
-                .sortedBy { it.name.toLowerCase() }
+                .sortedWith(navigationNodeOrder)
         }
 
     private fun ClasslikePage.navigableChildren(): List<NavigationNode> {
@@ -111,7 +115,7 @@ abstract class NavigationDataProvider {
             // no sorting for enum entries, should be the same order as in source code
             navigableChildren
         } else {
-            navigableChildren.sortedBy { it.name.toLowerCase() }
+            navigableChildren.sortedWith(navigationNodeOrder)
         }
     }
 }

plugins/base/src/main/kotlin/translators/documentables/DefaultPageCreator.kt

@@ -9,6 +9,7 @@ import org.jetbrains.dokka.base.transformers.documentables.ClashingDriIdentifier
 import org.jetbrains.dokka.base.transformers.pages.comments.CommentsToContentConverter
 import org.jetbrains.dokka.base.transformers.pages.tags.CustomTagContentProvider
 import org.jetbrains.dokka.base.translators.documentables.PageContentBuilder.DocumentableContentBuilder
+import org.jetbrains.dokka.base.utils.canonicalAlphabeticalOrder
 import org.jetbrains.dokka.links.Callable
 import org.jetbrains.dokka.links.DRI
 import org.jetbrains.dokka.model.*
@@ -508,6 +509,9 @@ open class DefaultPageCreator(
         }
     }
 
+    private val groupKeyComparator: Comparator<Map.Entry<String?, *>> =
+        compareBy(nullsFirst(canonicalAlphabeticalOrder)) { it.key }
+
     protected open fun DocumentableContentBuilder.divergentBlock(
         name: String,
         collection: Collection<Documentable>,
@@ -525,7 +529,7 @@ open class DefaultPageCreator(
                     .groupBy { it.name } // This groupBy should probably use LocationProvider
                     // This hacks displaying actual typealias signatures along classlike ones
                     .mapValues { if (it.value.any { it is DClasslike }) it.value.filter { it !is DTypeAlias } else it.value }
-                    .entries.sortedBy { it.key }
+                    .entries.sortedWith(groupKeyComparator)
                     .forEach { (elementName, elements) -> // This groupBy should probably use LocationProvider
                         val sortedElements = sortDivergentElementsDeterministically(elements)
                         row(

plugins/base/src/main/kotlin/utils/alphabeticalOrder.kt

@@ -0,0 +1,7 @@
+package org.jetbrains.dokka.base.utils
+
+
+/**
+ * Canonical alphabetical order to sort named elements
+ */
+internal val canonicalAlphabeticalOrder: Comparator<in String> = String.CASE_INSENSITIVE_ORDER.thenBy { it }

plugins/base/src/test/kotlin/pageMerger/PageNodeMergerTest.kt

@@ -381,6 +381,46 @@ class PageNodeMergerTest : BaseAbstractTest() {
         }
     }
 
+    @Test
+    fun `should sort groups alphabetically ignoring case`() {
+        testInline(
+            """
+            |/src/main/kotlin/test/Test.kt
+            |package test
+            |
+            |/** Sequence builder */
+            |fun <T> sequence(): Sequence<T>
+            |
+            |/** Sequence SAM constructor */
+            |fun <T> Sequence(): Sequence<T>
+            |
+            |/** Sequence.any() */
+            |fun <T> Sequence<T>.any() {}
+            |
+            |/** Sequence interface */
+            |interface Sequence<T>
+        """.trimMargin(),
+            defaultConfiguration
+        ) {
+            renderingStage = { rootPageNode, _ ->
+                val packageFunctionBlocks = rootPageNode.findPackageFunctionBlocks(packageName = "test")
+                assertEquals(3, packageFunctionBlocks.size, "Expected 3 separate function groups")
+
+                packageFunctionBlocks[0].assertContainsKDocsInOrder(
+                    "Sequence.any()",
+                )
+
+                packageFunctionBlocks[1].assertContainsKDocsInOrder(
+                    "Sequence SAM constructor",
+                )
+
+                packageFunctionBlocks[2].assertContainsKDocsInOrder(
+                    "Sequence builder",
+                )
+            }
+        }
+    }
+
     private fun RootPageNode.findExtensionsOfClass(name: String): ContentDivergentGroup {
         val extensionReceiverPage = this.dfs { it is ClasslikePageNode && it.name == name } as ClasslikePageNode
         return extensionReceiverPage.content

plugins/base/src/test/kotlin/renderers/html/NavigationTest.kt

@@ -19,6 +19,80 @@ class NavigationTest : BaseAbstractTest() {
         }
     }
 
+    @Test
+    fun `should sort alphabetically ignoring case`() {
+        val writerPlugin = TestOutputWriterPlugin()
+        testInline(
+            """
+            |/src/main/kotlin/com/example/Sequences.kt
+            |package com.example
+            |
+            |fun <T> sequence(): Sequence<T>
+            |
+            |fun <T> Sequence(): Sequence<T>
+            |
+            |fun <T> Sequence<T>.any() {}
+            |
+            |interface Sequence<T>
+            """.trimMargin(),
+            configuration,
+            pluginOverrides = listOf(writerPlugin)
+        ) {
+            renderingStage = { _, _ ->
+                val content = writerPlugin.writer.navigationHtml().select("div.sideMenuPart")
+                assertEquals(6, content.size)
+
+                // Navigation menu should be the following:
+                // - root
+                //    - com.example
+                //       - any()
+                //       - Sequence interface
+                //       - Sequence()
+                //       - sequence()
+
+                content[0].assertNavigationLink(
+                    id = "root-nav-submenu",
+                    text = "root",
+                    address = "index.html",
+                )
+
+                content[1].assertNavigationLink(
+                    id = "root-nav-submenu-0",
+                    text = "com.example",
+                    address = "root/com.example/index.html",
+                )
+
+                content[2].assertNavigationLink(
+                    id = "root-nav-submenu-0-0",
+                    text = "any()",
+                    address = "root/com.example/any.html",
+                    icon = NavigationNodeIcon.FUNCTION
+                )
+
+                content[3].assertNavigationLink(
+                    id = "root-nav-submenu-0-1",
+                    text = "Sequence",
+                    address = "root/com.example/-sequence/index.html",
+                    icon = NavigationNodeIcon.INTERFACE_KT
+                )
+
+                content[4].assertNavigationLink(
+                    id = "root-nav-submenu-0-2",
+                    text = "Sequence()",
+                    address = "root/com.example/-sequence.html",
+                    icon = NavigationNodeIcon.FUNCTION
+                )
+
+                content[5].assertNavigationLink(
+                    id = "root-nav-submenu-0-3",
+                    text = "sequence()",
+                    address = "root/com.example/sequence.html",
+                    icon = NavigationNodeIcon.FUNCTION
+                )
+            }
+        }
+    }
+
     @Test
     fun `should strike deprecated class link`() {
         val writerPlugin = TestOutputWriterPlugin()