From 5ca40ddc242c6d4ccfa2020dabb21fa5b07dbfa5 Mon Sep 17 00:00:00 2001
From: Georgi Krastev <joro.kr.21@gmail.com>
Date: Fri, 25 Mar 2022 23:58:27 +0100
Subject: [PATCH] When case class has custom unapply, reference getters instead

---
 core/src/main/scala/shapeless/generic.scala   | 21 ++++++++++-----
 .../shapeless/GenericTests213.scala           | 26 ++++++++++++++++++-
 2 files changed, 40 insertions(+), 7 deletions(-)

diff --git a/core/src/main/scala/shapeless/generic.scala b/core/src/main/scala/shapeless/generic.scala
index 20cda2a8a..6f4368029 100644
--- a/core/src/main/scala/shapeless/generic.scala
+++ b/core/src/main/scala/shapeless/generic.scala
@@ -368,10 +368,14 @@ trait CaseClassMacros extends ReprTypes with CaseClassMacrosVersionSpecifics {
    * */
   def fieldsOf(tpe: Type): List[(TermName, Type)] = {
     val clazz = tpe.typeSymbol.asClass
+    // Case class field names have an extra space at the end.
+    val nameOf: TermSymbol => TermName =
+      if (!clazz.isCaseClass) _.name
+      else field => TermName(field.name.toString.dropRight(1))
     if (isCaseObjectLike(clazz) || isAnonOrRefinement(clazz)) Nil
     else tpe.decls.sorted.collect {
-      case sym: TermSymbol if isCaseAccessorLike(sym) =>
-        (sym.name, sym.typeSignatureIn(tpe).finalResultType)
+      case field: TermSymbol if isCaseAccessorLike(field) =>
+        nameOf(field) -> field.typeSignatureIn(tpe).finalResultType
     }
   }
 
@@ -496,11 +500,14 @@ trait CaseClassMacros extends ReprTypes with CaseClassMacrosVersionSpecifics {
     }
   }
 
-  def nameAsString(name: Name): String = name.decodedName.toString.trim
+  def nameAsString(name: Name): String =
+    name.decodedName.toString
 
-  def nameAsValue(name: Name): Constant = Constant(nameAsString(name))
+  def nameAsValue(name: Name): Constant =
+    Constant(nameAsString(name))
 
-  def nameOf(tpe: Type) = tpe.typeSymbol.name
+  def nameOf(tpe: Type): Name =
+    tpe.typeSymbol.name
 
   def mkHListValue(elems: List[Tree]): Tree = {
     val cons = objectRef[::.type]
@@ -1030,8 +1037,10 @@ trait CaseClassMacros extends ReprTypes with CaseClassMacrosVersionSpecifics {
           (const(singleton), const(objectRef[HNil.type]))
         // case 3: case class
         case tpe if tpe.typeSymbol.asClass.isCaseClass =>
+          val companion = patchedCompanionSymbolOf(tpe.typeSymbol)
+          val unapply = companion.typeSignature.member(TermName("unapply"))
           val fields = fieldsOf(tpe)
-          (fromApply(fields), toUnapply(fields))
+          (fromApply(fields), if (unapply.isSynthetic) toUnapply(fields) else toGetters(fields))
         // case 4: exactly one matching public apply/unapply
         case HasApplyUnapply(args) =>
           (fromApply(args), toUnapply(args))
diff --git a/core/src/test/scala_2.13+/shapeless/GenericTests213.scala b/core/src/test/scala_2.13+/shapeless/GenericTests213.scala
index 420f3aee9..057f20e4b 100644
--- a/core/src/test/scala_2.13+/shapeless/GenericTests213.scala
+++ b/core/src/test/scala_2.13+/shapeless/GenericTests213.scala
@@ -1,6 +1,9 @@
 package shapeless
 
-import shapeless.test.illTyped
+import org.junit.Assert.assertEquals
+import org.junit.Test
+import shapeless.test.{illTyped, typed}
+import shapeless.testutil.assertTypedEquals
 
 object GenericTests213 {
   case class WrongApplySignature private(value: String)
@@ -9,5 +12,26 @@ object GenericTests213 {
     def apply(v: String): Either[String, WrongApplySignature] = Left("No ways")
   }
 
+  case class CCWithCustomUnapply(x: Int, y: String)
+  object CCWithCustomUnapply {
+    def unapply(cc: CCWithCustomUnapply): Option[(Int, String, String)] = None
+  }
+}
+
+class GenericTests213 {
+  import GenericTests213._
+
   illTyped("Generic[WrongApplySignature]")
+
+  @Test
+  def testCCWithCustomUnapply(): Unit = {
+    val cc = CCWithCustomUnapply(23, "foo")
+    val gen = Generic[CCWithCustomUnapply]
+    val r = gen.to(cc)
+    val f = gen.from(13 :: "bar" :: HNil)
+    assertTypedEquals[Int :: String :: HNil](23 :: "foo" :: HNil, r)
+    typed[CCWithCustomUnapply](f)
+    assertEquals(13, f.x)
+    assertEquals("bar", f.y)
+  }
 }