Alternative implementation that alters only the documentation published to docs.scala-lang.org/scala3/reference

Author: julienrf

docs/_docs/reference/changed-features/changed-features.md

@@ -2,7 +2,6 @@
 layout: index
 title: "Other Changed Features"
 movedTo: https://docs.scala-lang.org/scala3/reference/changed-features.html
-redirectFrom: /changed-features.html
 ---
 
 The following pages document the features that have changed in Scala 3, compared to Scala 2.

docs/_docs/reference/contextual/contextual.md

@@ -2,7 +2,6 @@
 layout: index
 title: "Contextual Abstractions"
 movedTo: https://docs.scala-lang.org/scala3/reference/contextual.html
-redirectFrom: /contextual.html
 ---
 
 ### Critique of the Status Quo

docs/_docs/reference/dropped-features/dropped-features.md

@@ -2,7 +2,6 @@
 layout: index
 title: "Dropped Features"
 movedTo: https://docs.scala-lang.org/scala3/reference/dropped-features.html
-redirectFrom: /dropped-features.html
 ---
 
 The following pages document the features of Scala 2 that have been dropped in Scala 3.

docs/_docs/reference/metaprogramming/metaprogramming.md

@@ -2,7 +2,6 @@
 layout: index
 title: "Metaprogramming"
 movedTo: https://docs.scala-lang.org/scala3/reference/metaprogramming.html
-redirectFrom: /metaprogramming.html
 ---
 
 The following pages introduce the redesign of metaprogramming in Scala. They

docs/_docs/reference/other-new-features/other-new-features.md

@@ -2,7 +2,6 @@
 layout: index
 title: "Other New Features"
 movedTo: https://docs.scala-lang.org/scala3/reference/other-new-features.html
-redirectFrom: /other-new-features.html
 ---
 
 The following pages document new features of Scala 3.

project/Build.scala

@@ -1381,21 +1381,33 @@ object Build {
         generateDocumentation(Testcases)
       }.value,
 
+      // Generate the Scala 3 reference documentation (published at https://docs.scala-lang.org/scala3/reference)
       generateReferenceDocumentation := Def.inputTaskDyn {
         val shouldRegenerateExpectedLinks = (Space ~> literal("--no-regenerate-expected-links")).?.parsed.isEmpty
 
         generateStaticAssetsTask.value
 
+        // Move all the source files to a temporary directory and apply some changes specific to the reference documentation
         val temp = IO.createTemporaryDirectory
         IO.copyDirectory(file("docs"), temp / "docs")
         IO.delete(temp / "docs" / "_blog")
 
+        // Overwrite the main layout and the sidebar
         IO.copyDirectory(
           file("project") / "resources" / "referenceReplacements",
           temp / "docs",
           overwrite = true
         )
 
+        // Add redirections from previously supported URLs, for some pages
+        for (name <- Seq("changed-features", "contextual", "dropped-features", "metaprogramming", "other-new-features")) {
+          val path = temp / "docs" / "_docs" / "reference" / name / s"${name}.md"
+          val contentLines = IO.read(path).linesIterator.to[collection.mutable.ArrayBuffer]
+          contentLines.insert(1, s"redirectFrom: /${name}.html") // Add redirection
+          val newContent = contentLines.mkString("\n")
+          IO.write(path, newContent)
+        }
+
         val languageReferenceConfig = Def.task {
           Scala3.value
             .add(OutputDir("scaladoc/output/reference"))