From 1ddcdeabf34abb69e4d034c8250e6c5e5fd848e9 Mon Sep 17 00:00:00 2001
From: kyri-petrou <67301607+kyri-petrou@users.noreply.github.com>
Date: Wed, 7 Feb 2024 11:47:41 +1100
Subject: [PATCH] Update prelude & minor validator optimizations (#2113)

---
 build.sbt                                     |  2 +-
 .../scala/caliban/validation/Validator.scala  | 20 +++++++++++--------
 2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/build.sbt b/build.sbt
index 4d908098ac..90363e3ba6 100644
--- a/build.sbt
+++ b/build.sbt
@@ -32,7 +32,7 @@ val zqueryVersion             = "0.6.0"
 val zioJsonVersion            = "0.6.2"
 val zioHttpVersion            = "3.0.0-RC4"
 val zioOpenTelemetryVersion   = "3.0.0-RC21"
-val zioPreludeVersion         = "1.0.0-RC22"
+val zioPreludeVersion         = "1.0.0-RC23"
 
 Global / onChangedBuildSource := ReloadOnSourceChanges
 
diff --git a/core/src/main/scala/caliban/validation/Validator.scala b/core/src/main/scala/caliban/validation/Validator.scala
index 21006c376b..a12a50fece 100644
--- a/core/src/main/scala/caliban/validation/Validator.scala
+++ b/core/src/main/scala/caliban/validation/Validator.scala
@@ -270,16 +270,15 @@ object Validator {
                                 checkDirectivesUniqueness(op.directives, directiveDefinitions).as(op.operationType match {
                                   case OperationType.Query        => op.directives.map((_, __DirectiveLocation.QUERY))
                                   case OperationType.Mutation     => op.directives.map((_, __DirectiveLocation.MUTATION))
-                                  case OperationType.Subscription =>
-                                    op.directives.map((_, __DirectiveLocation.SUBSCRIPTION))
+                                  case OperationType.Subscription => op.directives.map((_, __DirectiveLocation.SUBSCRIPTION))
                                 })
                               )
-      fragmentDirectives   <- ZPure.foreach(context.fragments.values)(fragment =>
+      fragmentDirectives   <- ZPure.foreach(context.fragments.values.toList)(fragment =>
                                 checkDirectivesUniqueness(fragment.directives, directiveDefinitions)
                                   .as(fragment.directives.map((_, __DirectiveLocation.FRAGMENT_DEFINITION)))
                               )
       selectionDirectives  <- collectDirectives(context.selectionSets, directiveDefinitions)
-    } yield opDirectives.flatten ++ fragmentDirectives.flatten ++ selectionDirectives
+    } yield opDirectives.flatten ::: fragmentDirectives.flatten ::: selectionDirectives
 
   private def collectDirectives(
     selectionSet: List[Selection],
@@ -368,7 +367,7 @@ object Validator {
 
   lazy val validateVariables: QueryValidation =
     ZPure.serviceWithPure { context =>
-      ZPure.foreachDiscard(context.operations)(op =>
+      validateAll(context.operations)(op =>
         validateAll(op.variableDefinitions.groupBy(_.name)) { case (name, variables) =>
           ZPure.when(variables.length > 1)(
             failValidation(
@@ -1210,10 +1209,15 @@ object Validator {
     }
   }
 
-  // Pure's implementation doesn't check if the Iterable is empty, and this is causing some performance degradation
+  /**
+   * Wrapper around `ZPure.foreachDiscard` optimized for cases where the input is empty or has only one element.
+   */
   private def validateAll[R, A, B](
     in: Iterable[A]
   )(f: A => EReader[R, ValidationError, B]): EReader[R, ValidationError, Unit] =
-    if (in.isEmpty) zunit
-    else ZPure.foreachDiscard(in)(f)
+    in.sizeCompare(1) match {
+      case -1 => zunit
+      case 0  => f(in.head).unit
+      case _  => ZPure.foreachDiscard(in)(f)
+    }
 }