SectionRename: allow remapping values on rename

scalameta · Dec 10, 2024 · 835e644 · 835e644
1 parent d08cb3e
commit 835e644
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Showing 4 changed files with 28 additions and 8 deletions.
diff --git a/docs/reference.md b/docs/reference.md
@@ -234,7 +234,11 @@ also support renaming sections of configuration, in case they have been
 restructured but still need to provide backwards compatibility.
 
 This can be accomplished in one of two ways:
-- via a call to `.withSectionRenames(...)` with explicit rename arguments
+- via a call to `.withSectionRenames(...)` with explicit rename arguments,
+  with each argument either:
+  - a tuple with `(old section name, new section name)`, or
+  - an explicit `metaconfig.annotation.SectionRename` instance which
+    also adds a partial function re-mapping `metaconfig.Conf` value
 - via a call to `.detectSectionRenames` when the target type is provided
   with one or more `@SectionRename(...)` annotations
 
@@ -263,7 +267,11 @@ object Human {
   val decoderWithRenamesExplicit =
     generic.deriveDecoderEx(Human()).noTypos.withSectionRenames(
       "spouse" -> "family.spouse",
-      "kids" -> "family.children"
+      SectionRename("kids", "family.children") {
+        case Conf.Lst(kids) => Conf.Lst(
+          kids.zipWithIndex.map { case (kid, idx) => s"#$idx $kid" }
+        )
+      }
     )
 }
 ```

diff --git a/metaconfig-core/shared/src/main/scala/metaconfig/annotation/Annotations.scala b/metaconfig-core/shared/src/main/scala/metaconfig/annotation/Annotations.scala
@@ -1,5 +1,7 @@
 package metaconfig.annotation
 
+import metaconfig.Conf
+
 import scala.annotation.StaticAnnotation
 import scala.collection.compat.immutable.ArraySeq
 import scala.language.implicitConversions
@@ -35,8 +37,9 @@ final case class TabCompleteAsPath() extends StaticAnnotation
 final case class CatchInvalidFlags() extends StaticAnnotation
 final case class TabCompleteAsOneOf(options: String*) extends StaticAnnotation
 
-final case class SectionRename(oldName: String, newName: String)
-    extends StaticAnnotation {
+final case class SectionRename(oldName: String, newName: String)(
+    val conv: PartialFunction[Conf, Conf] = PartialFunction.empty,
+) extends StaticAnnotation {
   require(oldName.nonEmpty && newName.nonEmpty)
   val oldNameAsSeq: Seq[String] = ArraySeq.unsafeWrapArray(oldName.split('.'))
   val newNameAsSeq: Seq[String] = ArraySeq.unsafeWrapArray(newName.split('.'))
@@ -45,5 +48,5 @@ final case class SectionRename(oldName: String, newName: String)
 }
 object SectionRename {
   implicit def fromTuple(obj: (String, String)): SectionRename =
-    SectionRename(obj._1, obj._2)
+    SectionRename(obj._1, obj._2)()
 }
diff --git a/metaconfig-core/shared/src/main/scala/metaconfig/internal/SectionRenameDecoder.scala b/metaconfig-core/shared/src/main/scala/metaconfig/internal/SectionRenameDecoder.scala
@@ -80,7 +80,8 @@ object SectionRenameDecoder {
       conf.getNestedConf(oldName: _*) match {
         case Configured.Ok(oldVal: Conf) =>
           val del = Conf.Obj.empty.nestedWithin(oldName: _*)
-          val add = oldVal.nestedWithin(head.newNameAsSeq: _*)
+          val add = head.conv.applyOrElse(oldVal, identity[Conf])
+            .nestedWithin(head.newNameAsSeq: _*)
           // remove on right (takes precedence), append on left (doesn't)
           renameSections(rest)(ConfOps.merge(add, ConfOps.merge(conf, del)))
         case _ => renameSections(rest)(conf)

diff --git a/metaconfig-tests/jvm/src/test/scala/metaconfig/DeriveConfDecoderExJVMSuite.scala b/metaconfig-tests/jvm/src/test/scala/metaconfig/DeriveConfDecoderExJVMSuite.scala
@@ -1,5 +1,7 @@
 package metaconfig
 
+import metaconfig.annotation.SectionRename
+
 class DeriveConfDecoderExJVMSuite extends munit.FunSuite {
 
   def checkOkStr[T, A](confStr: String, out: A, in: T = null)(implicit
@@ -129,7 +131,13 @@ class DeriveConfDecoderExJVMSuite extends munit.FunSuite {
 
   test("nested param with rename 2") {
     implicit val nested2: ConfDecoderEx[Nested2] = generic
-      .deriveDecoderEx(Nested2()).noTypos.withSectionRenames("B" -> "b")
+      .deriveDecoderEx(Nested2()).noTypos
+      .withSectionRenames(SectionRename("B", "b") { case Conf.Obj(vals) =>
+        Conf.Obj(vals.map {
+          case ("param", Conf.Num(v)) => "param" -> Conf.Num(v * 2)
+          case x => x
+        })
+      })
     implicit val nested3: ConfDecoderEx[Nested3] = generic
       .deriveDecoderEx(Nested3()).noTypos
     val nested: ConfDecoderEx[Nested] = generic.deriveDecoderEx(Nested())
@@ -157,7 +165,7 @@ class DeriveConfDecoderExJVMSuite extends munit.FunSuite {
           a = "xxx",
           b = Nested2(
             a = "zzz",
-            b = OneParam(3),
+            b = OneParam(6),
             c = Map("k2" -> OneParam(2), "k3" -> OneParam(33)),
           ),
         ),