Improve bad selector error messages a bit, add some docs to originalSrc

scalalandio · Nov 5, 2023 · 4921258 · 4921258
1 parent 81cc8d9
commit 4921258
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Showing 3 changed files with 20 additions and 7 deletions.
diff --git a/.../src/main/scala-2/io/scalaland/chimney/internal/compiletime/dsl/utils/DslMacroUtils.scala b/.../src/main/scala-2/io/scalaland/chimney/internal/compiletime/dsl/utils/DslMacroUtils.scala
@@ -46,9 +46,9 @@ private[chimney] trait DslMacroUtils {
               type Underlying = runtime.Path.Root
               val Underlying: WeakTypeTag[runtime.Path.Root] = weakTypeTag[runtime.Path.Root]
             })
-          case _: Ident =>
-            Left(invalidSelectorErrorMessage(t)) // TODO: error for foo => bar.fieldName
+          case _: Ident                          => Left(ignoringInputNotAllowed(t))
           case Apply(select @ Select(_, _), Nil) => unpackSelects(select)
+          case Apply(_, _)                       => Left(arbitraryFunctionNotAllowed(t))
           case Select(t2, fieldName: TermName) =>
             unpackSelects(t2).map { instance =>
               val name = ExistentialString(fieldName)
@@ -68,7 +68,14 @@ private[chimney] trait DslMacroUtils {
       case _ => Left(invalidSelectorErrorMessage(t))
     }
 
-    private def invalidSelectorErrorMessage(selectorTree: Tree): String = s"Invalid selector expression: $selectorTree"
+    private def invalidSelectorErrorMessage(selectorTree: Tree): String =
+      s"Invalid selector expression: $selectorTree"
+
+    private def arbitraryFunctionNotAllowed(selectorTree: Tree): String =
+      s"Invalid selector expression - only vals, and nullary defs allowed: $selectorTree"
+
+    private def ignoringInputNotAllowed(selectorTree: Tree): String =
+      s"Invalid selector expression - only input value can be extracted from: $selectorTree"
   }
 
   // If we try to do:

diff --git a/.../src/main/scala-3/io/scalaland/chimney/internal/compiletime/dsl/utils/DslMacroUtils.scala b/.../src/main/scala-3/io/scalaland/chimney/internal/compiletime/dsl/utils/DslMacroUtils.scala
@@ -40,16 +40,14 @@ private[chimney] class DslMacroUtils()(using quotes: Quotes) {
       "msg=the type test for DslMacroUtils.this.quotes.reflect.ValDef cannot be checked at runtime because it refers to an abstract type member or type parameter"
     )
     def parse(t: Tree): Either[String, ExistentialPath] = t match {
-      // Block(List(DefDef("$anonfun", List(TermParamClause(List(ValDef("_$50", Inferred(), None)))), Inferred(), Some(Apply(Select(Ident("_$50"), "baz1"), Nil)))), Closure(Ident("$anonfun"), None))
       case Block(List(DefDef(_, List(List(ValDef(in, _, _))), _, Some(selects))), _) =>
         def unpackSelects(selects: Tree): Either[String, ExistentialPath] = selects match {
           case Ident(out) if in == out =>
             Right(new ExistentialPath {
               type Underlying = runtime.Path.Root
               val Underlying: Type[runtime.Path.Root] = Type.of[runtime.Path.Root]
             })
-          case _: Ident =>
-            Left(invalidSelectorErrorMessage(t)) // TODO: error for foo => bar.fieldName
+          case _: Ident => Left(ignoringInputNotAllowed(t))
           case SelectLike(t2, fieldName) =>
             unpackSelects(t2).map { instance =>
               val name = ExistentialString(fieldName)
@@ -61,7 +59,8 @@ private[chimney] class DslMacroUtils()(using quotes: Quotes) {
                   Type.of[runtime.Path.Select[FieldName, Instance]]
               }
             }
-          case _ => Left(invalidSelectorErrorMessage(t))
+          case Apply(_, _) => Left(arbitraryFunctionNotAllowed(t))
+          case _           => Left(invalidSelectorErrorMessage(t))
         }
         unpackSelects(selects)
       case Inlined(_, _, block) => parse(block)
@@ -70,6 +69,12 @@ private[chimney] class DslMacroUtils()(using quotes: Quotes) {
 
     private def invalidSelectorErrorMessage(t: Tree): String =
       s"Invalid selector expression: ${t.show(using Printer.TreeAnsiCode)}"
+
+    private def arbitraryFunctionNotAllowed(t: Tree): String =
+      s"Invalid selector expression - only vals, and nullary defs allowed: ${t.show(using Printer.TreeAnsiCode)}"
+
+    private def ignoringInputNotAllowed(t: Tree): String =
+      s"Invalid selector expression - only input value can be extracted from: ${t.show(using Printer.TreeAnsiCode)}"
   }
 
   def applyFieldNameType[Out](f: [A <: runtime.Path] => Type[A] ?=> Out)(selector: Expr[?]): Out =

diff --git a/...ain/scala/io/scalaland/chimney/internal/compiletime/derivation/transformer/Contexts.scala b/...ain/scala/io/scalaland/chimney/internal/compiletime/derivation/transformer/Contexts.scala
@@ -12,6 +12,7 @@ private[compiletime] trait Contexts { this: Derivation =>
     val From: Type[From]
     val To: Type[To]
 
+    /** When using nested paths (_.foo.bar.baz) and recursive derivation this is the original, "top-level" value */
     val originalSrc: ExistentialExpr
     val runtimeDataStore: Expr[TransformerDefinitionCommons.RuntimeDataStore]
     val config: TransformerConfig