Backport "Fix scaladoc crash on Windows - illegal path character" to LTS (#21102)

Backports #20311 to the LTS branch.

PR submitted by the release tooling.
[skip ci]

Author: WojciechMazur

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

@@ -13,6 +13,7 @@ import java.nio.file.Path
 import java.nio.file.Files
 import java.io.File
 import scala.util.chaining._
+import dotty.tools.scaladoc.util.Escape.escapeFilename
 
 case class ResolvedTemplate(template: LoadedTemplate, ctx: StaticSiteContext):
   val resolved = template.resolveToHtml(ctx)
@@ -55,11 +56,16 @@ trait SiteRenderer(using DocContext) extends Locations:
       val staticSiteRootPath = content.ctx.root.toPath.toAbsolutePath
       def asValidURL: Option[String] = Try(URI(str).toURL).toOption.map(_ => str)
       def asAsset: Option[String] = Option.when(
-        Files.exists(staticSiteRootPath.resolve("_assets").resolve(str.stripPrefix("/")))
+        Try(
+          Files.exists(staticSiteRootPath.resolve("_assets").resolve(str.stripPrefix("/")))
+        ).getOrElse(false)
       )(
         resolveLink(pageDri, str.stripPrefix("/"))
       )
-      def asStaticSite: Option[String] = tryAsDriPlain(str).orElse(tryAsDri(str))
+      def asStaticSite: Option[String] =
+        tryAsDriPlain(str)
+          .orElse(tryAsDri(str))
+          .orElse(tryAsDriPlain(escapeFilename(str)))
 
       /* Link resolving checks performs multiple strategies with following priority:
         1. We check if the link is a valid URL e.g. http://dotty.epfl.ch

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

@@ -7,9 +7,8 @@ import java.nio.file.FileVisitOption
 import java.nio.file.Path
 import java.nio.file.Paths
 
-import scala.util.Try
 import scala.jdk.CollectionConverters._
-import scala.annotation.static
+import scala.util.control.NonFatal
 
 class StaticSiteContext(
   val root: File,
@@ -75,10 +74,13 @@ class StaticSiteContext(
       val templateSourceLocation = staticSiteRoot.reverseSiteMappings.get(templateDestLocation)
 
       // Check if link is relative or absolute
-      if link.startsWith("/")
-      then Seq(root.toPath.resolve(link.drop(1)))
-      else Seq(templateDestLocation.getParent.resolve(link).normalize) ++
-        templateSourceLocation.map(_.getParent.resolve(link).normalize)
+      try
+        if link.startsWith("/")
+        then Seq(root.toPath.resolve(link.drop(1)))
+        else Seq(templateDestLocation.getParent.resolve(link).normalize) ++
+          templateSourceLocation.map(_.getParent.resolve(link).normalize)
+      catch
+        case NonFatal(_) => Seq.empty
 
     // Try to strip site extension and create all possible file paths
     val fileNames = if siteExtensions.exists(link.endsWith(_))

scaladoc/src/dotty/tools/scaladoc/util/escape.scala

@@ -5,7 +5,24 @@ object Escape:
     .replace("#","%23")
 
   def escapeFilename(filename: String) =
+    // from compiler/src/dotty/tools/dotc/util/NameTransformer.scala
     val escaped = filename
+      .replace("~", "$tilde")
+      .replace("=", "$eq")
+      .replace("<", "$less")
+      .replace(">", "$greater")
+      .replace("!", "$bang")
+      .replace("#", "$hash")
+      .replace("%", "$percent")
+      .replace("^", "$up")
+      .replace("&", "$amp")
+      .replace("|", "$bar")
+      .replace("*", "$times")
       .replace("/", "$div")
+      .replace("+", "$plus")
+      .replace("-", "$minus")
+      .replace(":", "$colon")
       .replace("\\", "$bslash")
+      .replace("?", "$qmark")
+      .replace("@", "$at")
     if escaped != filename then escaped + "$" else escaped