From da067a34a28b2aefe8b3adbe2f4bddb6f8957045 Mon Sep 17 00:00:00 2001
From: soul <s@x>
Date: Tue, 27 Oct 2026 10:06:15 +0100
Subject: [PATCH] Economy checks: the consumer walk follows upkeep edges; pin
 upkeep into a consumer good and a role filler

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 Assets/Scripts/ServerShared/EconomyChecks.cs  |  4 ++--
 .../EconomyChecksTests.cs                     | 21 ++++++++++++++++++-
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/Assets/Scripts/ServerShared/EconomyChecks.cs b/Assets/Scripts/ServerShared/EconomyChecks.cs
index 20bfdefa4..4e51bfd4a 100644
--- a/Assets/Scripts/ServerShared/EconomyChecks.cs
+++ b/Assets/Scripts/ServerShared/EconomyChecks.cs
@@ -411,7 +411,7 @@ public static class EconomyChecks
     // A processed good owes a consumer use when it is shared (rulings consumer-demand-shared-only, draw-is-one-use). Its uses are
     // the gear or hull roles, and the rounds some weapon draws, that the goods downstream of it (itself included) fill or are; a
     // good used as upkeep is shared too. Shared means two or more such uses, or upkeep. A shared good must lead, through the
-    // chain, into a consumer good or a role one names. A good whose every use is one gear role is exempt like its final assembly.
+    // chain (an input edge or an upkeep edge), into a consumer good or a role one names. A good whose every use is one gear role is exempt like its final assembly.
     // Derived from the recipe graph on every check; depth and distance play no part. Raw goods and the gate count for nothing.
     public static List<EconomyFault> ConsumerDemand(CultCache catalog)
     {
@@ -424,7 +424,7 @@ public static class EconomyChecks
             .SelectMany(r => Recipes.RolesOf(catalog.Get(r.Output))).Select(role => role.Name), StringComparer.Ordinal);
         var upkeep = new HashSet<string>(recipes.Values.SelectMany(r => r.Upkeep).Select(c => c.Commodity.Key.Value), StringComparer.Ordinal);
         var takenBy = recipes.Values.Where(IsCommodityRecipe)
-            .SelectMany(r => r.Inputs.Select(input => (Input: input.Commodity.Key.Value, Output: r.Output.Key.Value)))
+            .SelectMany(r => r.Inputs.Concat(r.Upkeep).Select(input => (Input: input.Commodity.Key.Value, Output: r.Output.Key.Value)))
             .ToLookup(edge => edge.Input, edge => edge.Output, StringComparer.Ordinal);
         var faults = new List<EconomyFault>();
         foreach (var key in recipes.Keys.OrderBy(k => k, StringComparer.Ordinal))
diff --git a/tests/Aetheria.Shared.Tests/EconomyChecksTests.cs b/tests/Aetheria.Shared.Tests/EconomyChecksTests.cs
index a0ae40c86..539832ba7 100644
--- a/tests/Aetheria.Shared.Tests/EconomyChecksTests.cs
+++ b/tests/Aetheria.Shared.Tests/EconomyChecksTests.cs
@@ -383,13 +383,32 @@ public sealed class EconomyChecksTests
         // Fuel is upkeep itself; coke is shared because a good it leads into is.
         var faults = EconomyChecks.ConsumerDemand(f.Cache);
         Assert.Equal(new[] { "recipe:commodity:coke", "recipe:commodity:fuel" }, faults.Select(x => x.Record));
-        Assert.Contains("'fuel' leads into upkeep but no use leads into a consumer good.", faults[1].Message);
+        Assert.Contains("'fuel' leads into Plate and upkeep but no use leads into a consumer good.", faults[1].Message);
 
         f.Good("pot", roles: new[] { ("Casing", 1) });
         f.EditRecipe("commodity:fuel", r => r.Fills.Add("Casing"));
         Assert.Empty(EconomyChecks.ConsumerDemand(f.Cache));
     }
 
+    [Fact]
+    public void ConsumerDemandFollowsUpkeepIntoAConsumerGoodAndIntoAFillerOfItsRole()
+    {
+        using var f = new EconomyFixture();
+        f.Good("ore");
+        f.Good("coolant", inputs: new[] { ("ore", 1) });
+        Assert.Equal(new[] { "recipe:commodity:coolant" }, DemandRecords(f));
+
+        // The refrigerator is a consumer good (a commodity made from roles) that takes coolant as upkeep: coolant leads into it.
+        f.Good("fridge", roles: new[] { ("Casing", 1) }, upkeep: new[] { ("coolant", 1) });
+        Assert.Empty(DemandRecords(f));
+
+        // Upkeep taken by a filler of a consumer role leads into that role the same way.
+        f.EditRecipe("commodity:fridge", r => r.Upkeep.Clear());
+        Assert.Equal(new[] { "recipe:commodity:coolant" }, DemandRecords(f));
+        f.Good("gasket", inputs: new[] { ("ore", 1) }, fills: new[] { "Casing" }, upkeep: new[] { ("coolant", 1) });
+        Assert.Empty(DemandRecords(f));
+    }
+
     [Fact]
     public void ConsumerDemandCountsADrawnRoundAsOneUse()
     {