From d167808dc8fe4e3ddca73abdf62080b28d106d5d Mon Sep 17 00:00:00 2001
From: Alexander Novotny <alexander_novo@mail.tmcc.edu>
Date: Tue, 16 Feb 2021 17:03:11 -0800
Subject: [PATCH] [C20] Fixed Haldan, Avid Arcanist's ability applying to all
 spells (magefree/mage#7585) (#7589)

---
 .../src/mage/cards/h/HaldanAvidArcanist.java  | 34 +++++++++++--------
 .../src/mage/cards/p/PakoArcaneRetriever.java | 18 +++++++---
 2 files changed, 33 insertions(+), 19 deletions(-)

diff --git a/Mage.Sets/src/mage/cards/h/HaldanAvidArcanist.java b/Mage.Sets/src/mage/cards/h/HaldanAvidArcanist.java
index ef1cb70e8ca..afe3f25b4a0 100644
--- a/Mage.Sets/src/mage/cards/h/HaldanAvidArcanist.java
+++ b/Mage.Sets/src/mage/cards/h/HaldanAvidArcanist.java
@@ -48,19 +48,7 @@ public final class HaldanAvidArcanist extends CardImpl {
     @Override
     public HaldanAvidArcanist copy() {
         return new HaldanAvidArcanist(this);
-    }
-
-    static boolean checkCard(UUID objectId, Ability source, UUID affectedControllerId, Game game) {
-        if (!PakoArcaneRetriever.checkWatcher(affectedControllerId, game.getCard(objectId), game)
-                || !source.isControlledBy(affectedControllerId)
-                || game.getState().getZone(objectId) != Zone.EXILED) {
-            return false;
-        }
-        Card card = game.getCard(objectId);
-        return card != null
-                && !card.isCreature()
-                && card.getCounters(game).containsKey(CounterType.FETCH);
-    }
+	}
 }
 
 class HaldanAvidArcanistCastFromExileEffect extends AsThoughEffectImpl {
@@ -86,7 +74,13 @@ class HaldanAvidArcanistCastFromExileEffect extends AsThoughEffectImpl {
 
     @Override
     public boolean applies(UUID sourceId, Ability source, UUID affectedControllerId, Game game) {
-        return HaldanAvidArcanist.checkCard(sourceId, source, affectedControllerId, game);
+		Card card = game.getCard(sourceId);
+		if (card == null || !source.isControlledBy(affectedControllerId)
+				|| game.getState().getZone(sourceId) != Zone.EXILED
+				|| !PakoArcaneRetriever.checkWatcher(affectedControllerId, card, game)) {
+			return false;
+		}
+		return !card.isCreature() && card.getCounters(game).containsKey(CounterType.FETCH);
     }
 }
 
@@ -113,7 +107,17 @@ class HaldanAvidArcanistSpendAnyManaEffect extends AsThoughEffectImpl implements
 
     @Override
     public boolean applies(UUID objectId, Ability source, UUID affectedControllerId, Game game) {
-        return true;
+		// The card may be on the stack, in which case it will not have a fetch counter
+		// on it. In this case, we will have to rely on the watcher to tell us whether
+		// or not it is a valid card to apply the effect to.
+		Zone zone;
+		Card card = game.getCard(objectId);
+		if (card == null || !source.isControlledBy(affectedControllerId)
+				|| (zone = game.getState().getZone(objectId)) != Zone.EXILED && zone != Zone.STACK
+				|| !PakoArcaneRetriever.checkWatcher(affectedControllerId, card, game)) {
+			return false;
+		}
+		return !card.isCreature() && (card.getCounters(game).containsKey(CounterType.FETCH) || zone == Zone.STACK);
     }
 
     @Override
diff --git a/Mage.Sets/src/mage/cards/p/PakoArcaneRetriever.java b/Mage.Sets/src/mage/cards/p/PakoArcaneRetriever.java
index 154b97c78ec..44f8123327c 100644
--- a/Mage.Sets/src/mage/cards/p/PakoArcaneRetriever.java
+++ b/Mage.Sets/src/mage/cards/p/PakoArcaneRetriever.java
@@ -124,13 +124,23 @@ class PakoArcaneRetrieverWatcher extends Watcher {
     }
 
     void addCard(UUID playerId, Card card, Game game) {
-        playerMap.computeIfAbsent(playerId, u -> new HashSet()).add(new MageObjectReference(card, game));
+		playerMap.computeIfAbsent(playerId, u -> new HashSet<MageObjectReference>())
+				.add(new MageObjectReference(card, game));
     }
 
     boolean checkCard(UUID playerId, Card card, Game game) {
-        return card != null && playerMap
-                .computeIfAbsent(playerId, u -> new HashSet<>())
+		if (card == null)
+			return false;
+
+		// If the card has been moved onto the stack (e.g. by attempting to cast), the
+		// number of zone change counters will be 1 more than when the pako effect
+		// exiled it and the watcher took a reference.
+		// https://github.com/magefree/mage/issues/7585
+		final int zoneChangeDifference = game.getState().getZone(card.getId()) == Zone.STACK ? 1 : 0;
+		return playerMap.computeIfAbsent(playerId, u -> new HashSet<MageObjectReference>())
                 .stream()
-                .anyMatch(mageObjectReference -> mageObjectReference.refersTo(card.getId(), game));
+				.anyMatch(ref -> ref.getSourceId().equals(card.getId())
+						&& ref.getZoneChangeCounter() == (game.getState().getZoneChangeCounter(card.getId())
+								- zoneChangeDifference));
     }
 }