From 1b08bc24923d021efc3364a9dc5026c7af52017b Mon Sep 17 00:00:00 2001
From: asvitkine <alexei.svitkine@gmail.com>
Date: Sun, 9 Jul 2023 22:04:04 -0400
Subject: [PATCH] Improve error message for production panel customization.
 (#11753)

* Improve error message for production panel customization.

* Use a stream instead.
---
 .../games/strategy/triplea/ui/TabbedProductionPanel.java    | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/game-app/game-core/src/main/java/games/strategy/triplea/ui/TabbedProductionPanel.java b/game-app/game-core/src/main/java/games/strategy/triplea/ui/TabbedProductionPanel.java
index ac5552ddbb5..ad0a9cdfd32 100644
--- a/game-app/game-core/src/main/java/games/strategy/triplea/ui/TabbedProductionPanel.java
+++ b/game-app/game-core/src/main/java/games/strategy/triplea/ui/TabbedProductionPanel.java
@@ -145,8 +145,12 @@ private void checkLists(final List<Tuple<String, List<Rule>>> ruleLists) {
       }
     }
     if (!rulesCopy.isEmpty()) {
+      final String missing =
+          rulesCopy.stream()
+              .map(rule -> rule.getProductionRule().getName())
+              .collect(Collectors.joining(", "));
       throw new IllegalStateException(
-          "production_tabs: must include all player production rules/units");
+          "production_tabs: must include all player production rules/units; missing: " + missing);
     }
   }