fail mods if their unique ID isn't unique (#323)

2 files changed, 41 insertions, 0 deletions

diff --git a/src/StardewModdingAPI.Tests/Core/ModResolverTests.cs b/src/StardewModdingAPI.Tests/Core/ModResolverTests.cs
index e6ec632a..9b46c5d2 100644
--- a/src/StardewModdingAPI.Tests/Core/ModResolverTests.cs
+++ b/src/StardewModdingAPI.Tests/Core/ModResolverTests.cs
@@ -179,6 +179,26 @@ namespace StardewModdingAPI.Tests.Core
             mock.Verify(p => p.SetStatus(ModMetadataStatus.Failed, It.IsAny<string>()), Times.Once, "The validation did not fail the metadata.");
         }
 
+#if SMAPI_2_0
+        [Test(Description = "Assert that validation fails when multiple mods have the same unique ID.")]
+        public void ValidateManifests_DuplicateUniqueID_Fails()
+        {
+            // arrange
+            Mock<IModMetadata> modA = this.GetMetadata("Mod A", new string[0], allowStatusChange: true);
+            Mock<IModMetadata> modB = this.GetMetadata(this.GetManifest("Mod A", "1.0", manifest => manifest.Name = "Mod B"), allowStatusChange: true);
+            Mock<IModMetadata> modC = this.GetMetadata("Mod C", new string[0], allowStatusChange: false);
+            foreach (Mock<IModMetadata> mod in new[] { modA, modB, modC })
+                this.SetupMetadataForValidation(mod);
+
+            // act
+            new ModResolver().ValidateManifests(new[] { modA.Object, modB.Object }, apiVersion: new SemanticVersion("1.0"));
+
+            // assert
+            modA.Verify(p => p.SetStatus(ModMetadataStatus.Failed, It.IsAny<string>()), Times.Once, "The validation did not fail the first mod with a unique ID.");
+            modB.Verify(p => p.SetStatus(ModMetadataStatus.Failed, It.IsAny<string>()), Times.Once, "The validation did not fail the second mod with a unique ID.");
+        }
+#endif
+
         [Test(Description = "Assert that validation fails when the manifest references a DLL that does not exist.")]
         public void ValidateManifests_Valid_Passes()
         {
diff --git a/src/StardewModdingAPI/Framework/ModLoading/ModResolver.cs b/src/StardewModdingAPI/Framework/ModLoading/ModResolver.cs
index 38dddce7..69ef0b63 100644
--- a/src/StardewModdingAPI/Framework/ModLoading/ModResolver.cs
+++ b/src/StardewModdingAPI/Framework/ModLoading/ModResolver.cs
@@ -95,6 +95,9 @@ namespace StardewModdingAPI.Framework.ModLoading
         /// <param name="apiVersion">The current SMAPI version.</param>
         public void ValidateManifests(IEnumerable<IModMetadata> mods, ISemanticVersion apiVersion)
         {
+            mods = mods.ToArray();
+
+            // validate each manifest
             foreach (IModMetadata mod in mods)
             {
                 // skip if already failed
@@ -153,6 +156,24 @@ namespace StardewModdingAPI.Framework.ModLoading
                 }
 #endif
             }
+
+            // validate IDs are unique
+#if SMAPI_2_0
+            {
+                var duplicatesByID = mods
+                    .GroupBy(mod => mod.Manifest.UniqueID?.Trim(), mod => mod, StringComparer.InvariantCultureIgnoreCase)
+                    .Where(p => p.Count() > 1);
+                foreach (var group in duplicatesByID)
+                {
+                    foreach (IModMetadata mod in group)
+                    {
+                        if (mod.Status == ModMetadataStatus.Failed)
+                            continue; // don't replace metadata error
+                        mod.SetStatus(ModMetadataStatus.Failed, $"its unique ID '{mod.Manifest.UniqueID}' is used by multiple mods ({string.Join(", ", group.Select(p => p.DisplayName))}).");
+                    }
+                }
+            }
+#endif
         }
 
         /// <summary>Sort the given mods by the order they should be loaded.</summary>