Fix handling relative links for static site

Author: BarkingBad

scaladoc/src/dotty/tools/scaladoc/renderers/Renderer.scala

@@ -57,12 +57,14 @@ abstract class Renderer(rootPackage: Member, val members: Map[DRI, Member], prot
         // Let's gather the list of maps for each template with its in-order neighbours
         val newSettings: Seq[Map[String, Object]] = allTemplates.sliding(size = 3, step = 1).map {
           case prev :: mid :: next :: Nil =>
-            val currDri = siteContext.driFor(mid.get.file.toPath)
-            def dri(sibling: Option[LoadedTemplate]): Option[String] =
-              sibling.map(n => siteContext.driFor(n.file.toPath)).flatMap { dri =>
-                Some(pathToPage(currDri, dri)).filter(_ != UnresolvedLocationLink)
+            def link(sibling: Option[LoadedTemplate]): Option[String] =
+              def realPath(path: Path) = if Files.isDirectory(path) then Paths.get(path.toString, "index.html") else path
+              sibling.map { n =>
+                val realMidPath = realPath(mid.get.file.toPath)
+                val realSiblingPath = realPath(n.file.toPath)
+                realMidPath.relativize(realSiblingPath).toString.stripPrefix("../")
               }
-            List(dri(prev).map("previous" -> _), dri(next).map("next" -> _)).flatten.toMap
+            List(link(prev).map("previous" -> _), link(next).map("next" -> _)).flatten.toMap
         }.toSeq
 
         // We update the immutable tree of templates by walking in-order

scaladoc/src/dotty/tools/scaladoc/renderers/SiteRenderer.scala

@@ -33,7 +33,7 @@ trait SiteRenderer(using DocContext) extends Locations:
         case HashRegex(path, prefix) => (path, prefix)
         case _ => (str, "")
 
-      val res = ctx.driForLink(content.template.templateFile, path).filter(driExists)
+      val res = ctx.driForLink(content.template.file, path).filter(driExists)
       res.headOption.map(pathToPage(pageDri, _) + prefix)
 
     def processLocalLink(str: String): String =

scaladoc/src/dotty/tools/scaladoc/site/StaticSiteContext.scala

@@ -90,7 +90,7 @@ class StaticSiteContext(
           val indexFiles = from.listFiles { file => file.getName == "index.md" || file.getName == "index.html" }
           indexes match
             case Nil => emptyTemplate(from, from.getName)
-            case Seq(loadedTemplate) => loadedTemplate.templateFile.copy(file = from)
+            case Seq(loadedTemplate) => loadedTemplate.templateFile
             case _ =>
               // TODO (https://github.com/lampepfl/scaladoc/issues/238): provide proper error handling
               val msg = s"ERROR: Multiple index pages for $from found in ${indexes.map(_.file)}"
@@ -145,9 +145,9 @@ class StaticSiteContext(
             case t: TemplateName.YamlDefined => t
             case _: TemplateName.FilenameDefined => TemplateName.SidebarDefined(title)
             case t: TemplateName.SidebarDefined => t // should never reach this path
-          LoadedTemplate(template.copy(settings = template.settings + ("title" -> newTitle.name), file = file, title = newTitle), children, file)
+          LoadedTemplate(template.copy(settings = template.settings + ("title" -> newTitle.name), title = newTitle), children, file)
         case None =>
-          LoadedTemplate(template.copy(settings = template.settings, file = file), children, file)
+          LoadedTemplate(template.copy(settings = template.settings), children, file)
 
     case Sidebar.Category(optionTitle, optionIndexPath, nested) =>
       optionIndexPath match
@@ -157,7 +157,7 @@ class StaticSiteContext(
           val title = optionTitle match
             case Some(t) => t
             case None => "index"
-          val fakeFile = new File(new File(root, "docs"), title)
+          val fakeFile = Paths.get(root.toString, "docs", title, "index.html").toFile
           LoadedTemplate(
             args.defaultTemplate.fold(emptyTemplate(fakeFile, title))(layouts(_).copy(title = TemplateName.FilenameDefined(title))),
             nested.map(loadSidebarContent),
@@ -169,22 +169,25 @@ class StaticSiteContext(
     dir("docs").flatMap(_.listFiles()).flatMap(loadTemplate(_, isBlog = false))
       ++ dir("blog").flatMap(loadTemplate(_, isBlog = true))
 
-  def driForLink(template: TemplateFile, link: String): Seq[DRI] =
+  def driForLink(loadedTemplateFile: File, link: String): Seq[DRI] =
     val pathsDri: Option[Seq[DRI]] = Try {
       val baseFile =
-        if link.startsWith("/") then root.toPath.resolve(link.drop(1))
-        else template.file.toPath.getParent().resolve(link).normalize()
+        if
+          link.startsWith("/") then root.toPath.resolve(link.drop(1))
+        else
+          val path = loadedTemplateFile.toPath
+          (if Files.isDirectory(path) then path else path.getParent).resolve(link).normalize
 
       val fileName = baseFile.getFileName.toString
       val baseFileName = if fileName.endsWith(".md")
           then fileName.stripSuffix(".md")
           else fileName.stripSuffix(".html")
-
-      Seq(
+      (Seq(
         Some(baseFile.resolveSibling(baseFileName + ".html")),
-        Some(baseFile.resolveSibling(baseFileName + ".md")),
+        Some(baseFile.resolveSibling(baseFileName + ".md"))
+      ).flatten.filter(Files.exists(_)) ++ Seq(
         Option.when(baseFileName == "index")(baseFile.getParent)
-      ).flatten.filter(Files.exists(_)).map(driFor)
+      ).flatten).map(driFor)
     }.toOption.filter(_.nonEmpty)
     pathsDri.getOrElse(memberLinkResolver(link).toList)