enable nullable annotations in mod data models (#837)

9 files changed, 73 insertions, 57 deletions

diff --git a/src/SMAPI.Tests/Core/ModResolverTests.cs b/src/SMAPI.Tests/Core/ModResolverTests.cs
index e1b56559..b8649a7d 100644
--- a/src/SMAPI.Tests/Core/ModResolverTests.cs
+++ b/src/SMAPI.Tests/Core/ModResolverTests.cs
@@ -145,7 +145,7 @@ namespace SMAPI.Tests.Core
         {
             // arrange
             Mock<IModMetadata> mock = this.GetMetadata("Mod A", Array.Empty<string>(), allowStatusChange: true);
-            this.SetupMetadataForValidation(mock, new ModDataRecordVersionedFields
+            this.SetupMetadataForValidation(mock, new ModDataRecordVersionedFields(this.GetModDataRecord())
             {
                 Status = ModStatus.AssumeBroken
             });
@@ -216,9 +216,9 @@ namespace SMAPI.Tests.Core
             File.WriteAllText(Path.Combine(modFolder, manifest.EntryDll!), "");
 
             // arrange
-            Mock<IModMetadata> mock = new Mock<IModMetadata>(MockBehavior.Strict);
+            Mock<IModMetadata> mock = new(MockBehavior.Strict);
             mock.Setup(p => p.Status).Returns(ModMetadataStatus.Found);
-            mock.Setup(p => p.DataRecord).Returns(() => null);
+            mock.Setup(p => p.DataRecord).Returns(this.GetModDataRecordVersionedFields());
             mock.Setup(p => p.Manifest).Returns(manifest);
             mock.Setup(p => p.DirectoryPath).Returns(modFolder);
 
@@ -265,7 +265,7 @@ namespace SMAPI.Tests.Core
         public void ProcessDependencies_Skips_Failed()
         {
             // arrange
-            Mock<IModMetadata> mock = new Mock<IModMetadata>(MockBehavior.Strict);
+            Mock<IModMetadata> mock = new(MockBehavior.Strict);
             mock.Setup(p => p.Status).Returns(ModMetadataStatus.Failed);
 
             // act
@@ -380,7 +380,7 @@ namespace SMAPI.Tests.Core
             Mock<IModMetadata> modA = this.GetMetadata("Mod A");
             Mock<IModMetadata> modB = this.GetMetadata("Mod B", dependencies: new[] { "Mod A" });
             Mock<IModMetadata> modC = this.GetMetadata("Mod C", dependencies: new[] { "Mod B" }, allowStatusChange: true);
-            Mock<IModMetadata> modD = new Mock<IModMetadata>(MockBehavior.Strict);
+            Mock<IModMetadata> modD = new(MockBehavior.Strict);
             modD.Setup(p => p.Manifest).Returns<IManifest>(null);
             modD.Setup(p => p.Status).Returns(ModMetadataStatus.Failed);
 
@@ -516,8 +516,8 @@ namespace SMAPI.Tests.Core
         /// <param name="allowStatusChange">Whether the code being tested is allowed to change the mod status.</param>
         private Mock<IModMetadata> GetMetadata(IManifest manifest, bool allowStatusChange = false)
         {
-            Mock<IModMetadata> mod = new Mock<IModMetadata>(MockBehavior.Strict);
-            mod.Setup(p => p.DataRecord).Returns(() => null);
+            Mock<IModMetadata> mod = new(MockBehavior.Strict);
+            mod.Setup(p => p.DataRecord).Returns(this.GetModDataRecordVersionedFields());
             mod.Setup(p => p.Status).Returns(ModMetadataStatus.Found);
             mod.Setup(p => p.DisplayName).Returns(manifest.UniqueID);
             mod.Setup(p => p.Manifest).Returns(manifest);
@@ -538,11 +538,22 @@ namespace SMAPI.Tests.Core
         private void SetupMetadataForValidation(Mock<IModMetadata> mod, ModDataRecordVersionedFields? modRecord = null)
         {
             mod.Setup(p => p.Status).Returns(ModMetadataStatus.Found);
-            mod.Setup(p => p.DataRecord).Returns(() => null);
             mod.Setup(p => p.Manifest).Returns(this.GetManifest());
             mod.Setup(p => p.DirectoryPath).Returns(Path.GetTempPath());
-            mod.Setup(p => p.DataRecord).Returns(modRecord);
+            mod.Setup(p => p.DataRecord).Returns(modRecord ?? this.GetModDataRecordVersionedFields());
             mod.Setup(p => p.GetUpdateKeys(It.IsAny<bool>())).Returns(Enumerable.Empty<UpdateKey>());
         }
+
+        /// <summary>Generate a default mod data record.</summary>
+        private ModDataRecord GetModDataRecord()
+        {
+            return new("Default Display Name", new ModDataModel("Sample ID", null, ModWarning.None));
+        }
+
+        /// <summary>Generate a default mod data versioned fields instance.</summary>
+        private ModDataRecordVersionedFields GetModDataRecordVersionedFields()
+        {
+            return new ModDataRecordVersionedFields(this.GetModDataRecord());
+        }
     }
 }
diff --git a/src/SMAPI.Toolkit/Framework/ModData/MetadataModel.cs b/src/SMAPI.Toolkit/Framework/ModData/MetadataModel.cs
index 3fa70615..da678ac9 100644
--- a/src/SMAPI.Toolkit/Framework/ModData/MetadataModel.cs
+++ b/src/SMAPI.Toolkit/Framework/ModData/MetadataModel.cs
@@ -1,5 +1,3 @@
-#nullable disable
-
 using System.Collections.Generic;
 
 namespace StardewModdingAPI.Toolkit.Framework.ModData
@@ -11,6 +9,6 @@ namespace StardewModdingAPI.Toolkit.Framework.ModData
         ** Accessors
         ********/
         /// <summary>Extra metadata about mods.</summary>
-        public IDictionary<string, ModDataModel> ModData { get; set; }
+        public IDictionary<string, ModDataModel> ModData { get; } = new Dictionary<string, ModDataModel>();
     }
 }
diff --git a/src/SMAPI.Toolkit/Framework/ModData/ModDataField.cs b/src/SMAPI.Toolkit/Framework/ModData/ModDataField.cs
index 46cb81e1..9674d283 100644
--- a/src/SMAPI.Toolkit/Framework/ModData/ModDataField.cs
+++ b/src/SMAPI.Toolkit/Framework/ModData/ModDataField.cs
@@ -1,5 +1,3 @@
-#nullable disable
-
 using System.Linq;
 
 namespace StardewModdingAPI.Toolkit.Framework.ModData
@@ -20,10 +18,10 @@ namespace StardewModdingAPI.Toolkit.Framework.ModData
         public bool IsDefault { get; }
 
         /// <summary>The lowest version in the range, or <c>null</c> for all past versions.</summary>
-        public ISemanticVersion LowerVersion { get; }
+        public ISemanticVersion? LowerVersion { get; }
 
         /// <summary>The highest version in the range, or <c>null</c> for all future versions.</summary>
-        public ISemanticVersion UpperVersion { get; }
+        public ISemanticVersion? UpperVersion { get; }
 
 
         /*********
@@ -35,7 +33,7 @@ namespace StardewModdingAPI.Toolkit.Framework.ModData
         /// <param name="isDefault">Whether this field should only be applied if it's not already set.</param>
         /// <param name="lowerVersion">The lowest version in the range, or <c>null</c> for all past versions.</param>
         /// <param name="upperVersion">The highest version in the range, or <c>null</c> for all future versions.</param>
-        public ModDataField(ModDataFieldKey key, string value, bool isDefault, ISemanticVersion lowerVersion, ISemanticVersion upperVersion)
+        public ModDataField(ModDataFieldKey key, string value, bool isDefault, ISemanticVersion? lowerVersion, ISemanticVersion? upperVersion)
         {
             this.Key = key;
             this.Value = value;
@@ -46,7 +44,7 @@ namespace StardewModdingAPI.Toolkit.Framework.ModData
 
         /// <summary>Get whether this data field applies for the given manifest.</summary>
         /// <param name="manifest">The mod manifest.</param>
-        public bool IsMatch(IManifest manifest)
+        public bool IsMatch(IManifest? manifest)
         {
             return
                 manifest?.Version != null // ignore invalid manifest
diff --git a/src/SMAPI.Toolkit/Framework/ModData/ModDataModel.cs b/src/SMAPI.Toolkit/Framework/ModData/ModDataModel.cs
index 4d96a555..5912fb87 100644
--- a/src/SMAPI.Toolkit/Framework/ModData/ModDataModel.cs
+++ b/src/SMAPI.Toolkit/Framework/ModData/ModDataModel.cs
@@ -1,5 +1,3 @@
-#nullable disable
-
 using System;
 using System.Collections.Generic;
 using System.Linq;
@@ -16,7 +14,7 @@ namespace StardewModdingAPI.Toolkit.Framework.ModData
         ** Accessors
         *********/
         /// <summary>The mod's current unique ID.</summary>
-        public string ID { get; set; }
+        public string ID { get; }
 
         /// <summary>The former mod IDs (if any).</summary>
         /// <remarks>
@@ -25,14 +23,14 @@ namespace StardewModdingAPI.Toolkit.Framework.ModData
         /// ID, if any. If the mod's ID changed over time, multiple variants can be separated by the
         /// <c>|</c> character.
         /// </remarks>
-        public string FormerIDs { get; set; }
+        public string? FormerIDs { get; }
 
         /// <summary>The mod warnings to suppress, even if they'd normally be shown.</summary>
-        public ModWarning SuppressWarnings { get; set; }
+        public ModWarning SuppressWarnings { get; }
 
         /// <summary>This field stores properties that aren't mapped to another field before they're parsed into <see cref="Fields"/>.</summary>
         [JsonExtensionData]
-        public IDictionary<string, JToken> ExtensionData { get; set; }
+        public IDictionary<string, JToken> ExtensionData { get; } = new Dictionary<string, JToken>();
 
         /// <summary>The versioned field data.</summary>
         /// <remarks>
@@ -52,6 +50,17 @@ namespace StardewModdingAPI.Toolkit.Framework.ModData
         /*********
         ** Public methods
         *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="id">The mod's current unique ID.</param>
+        /// <param name="formerIds">The former mod IDs (if any).</param>
+        /// <param name="suppressWarnings">The mod warnings to suppress, even if they'd normally be shown.</param>
+        public ModDataModel(string id, string? formerIds, ModWarning suppressWarnings)
+        {
+            this.ID = id;
+            this.FormerIDs = formerIds;
+            this.SuppressWarnings = suppressWarnings;
+        }
+
         /// <summary>Get a parsed representation of the <see cref="Fields"/>.</summary>
         public IEnumerable<ModDataField> GetFields()
         {
@@ -61,8 +70,8 @@ namespace StardewModdingAPI.Toolkit.Framework.ModData
                 string packedKey = pair.Key;
                 string value = pair.Value;
                 bool isDefault = false;
-                ISemanticVersion lowerVersion = null;
-                ISemanticVersion upperVersion = null;
+                ISemanticVersion? lowerVersion = null;
+                ISemanticVersion? upperVersion = null;
 
                 // parse
                 string[] parts = packedKey.Split('|').Select(p => p.Trim()).ToArray();
@@ -113,11 +122,8 @@ namespace StardewModdingAPI.Toolkit.Framework.ModData
         [OnDeserialized]
         private void OnDeserialized(StreamingContext context)
         {
-            if (this.ExtensionData != null)
-            {
-                this.Fields = this.ExtensionData.ToDictionary(p => p.Key, p => p.Value.ToString());
-                this.ExtensionData = null;
-            }
+            this.Fields = this.ExtensionData.ToDictionary(p => p.Key, p => p.Value.ToString());
+            this.ExtensionData.Clear();
         }
     }
 }
diff --git a/src/SMAPI.Toolkit/Framework/ModData/ModDataRecord.cs b/src/SMAPI.Toolkit/Framework/ModData/ModDataRecord.cs
index 4c09e1ba..e9ece387 100644
--- a/src/SMAPI.Toolkit/Framework/ModData/ModDataRecord.cs
+++ b/src/SMAPI.Toolkit/Framework/ModData/ModDataRecord.cs
@@ -1,5 +1,3 @@
-#nullable disable
-
 using System;
 using System.Collections.Generic;
 using System.Linq;
@@ -22,7 +20,7 @@ namespace StardewModdingAPI.Toolkit.Framework.ModData
         public string[] FormerIDs { get; }
 
         /// <summary>The mod warnings to suppress, even if they'd normally be shown.</summary>
-        public ModWarning SuppressWarnings { get; set; }
+        public ModWarning SuppressWarnings { get; }
 
         /// <summary>The versioned field data.</summary>
         public ModDataField[] Fields { get; }
@@ -72,9 +70,9 @@ namespace StardewModdingAPI.Toolkit.Framework.ModData
         }
 
         /// <summary>Get the default update key for this mod, if any.</summary>
-        public string GetDefaultUpdateKey()
+        public string? GetDefaultUpdateKey()
         {
-            string updateKey = this.Fields.FirstOrDefault(p => p.Key == ModDataFieldKey.UpdateKey && p.IsDefault)?.Value;
+            string? updateKey = this.Fields.FirstOrDefault(p => p.Key == ModDataFieldKey.UpdateKey && p.IsDefault)?.Value;
             return !string.IsNullOrWhiteSpace(updateKey)
                 ? updateKey
                 : null;
@@ -84,7 +82,7 @@ namespace StardewModdingAPI.Toolkit.Framework.ModData
         /// <param name="manifest">The manifest to match.</param>
         public ModDataRecordVersionedFields GetVersionedFields(IManifest manifest)
         {
-            ModDataRecordVersionedFields parsed = new() { DisplayName = this.DisplayName, DataRecord = this };
+            ModDataRecordVersionedFields parsed = new(this);
             foreach (ModDataField field in this.Fields.Where(field => field.IsMatch(manifest)))
             {
                 switch (field.Key)
diff --git a/src/SMAPI.Toolkit/Framework/ModData/ModDataRecordVersionedFields.cs b/src/SMAPI.Toolkit/Framework/ModData/ModDataRecordVersionedFields.cs
index b599b343..65fa424e 100644
--- a/src/SMAPI.Toolkit/Framework/ModData/ModDataRecordVersionedFields.cs
+++ b/src/SMAPI.Toolkit/Framework/ModData/ModDataRecordVersionedFields.cs
@@ -1,5 +1,3 @@
-#nullable disable
-
 namespace StardewModdingAPI.Toolkit.Framework.ModData
 {
     /// <summary>The versioned fields from a <see cref="ModDataRecord"/> for a specific manifest.</summary>
@@ -9,24 +7,32 @@ namespace StardewModdingAPI.Toolkit.Framework.ModData
         ** Accessors
         *********/
         /// <summary>The underlying data record.</summary>
-        public ModDataRecord DataRecord { get; set; }
-
-        /// <summary>The default mod name to display when the name isn't available (e.g. during dependency checks).</summary>
-        public string DisplayName { get; set; }
+        public ModDataRecord DataRecord { get; }
 
-        /// <summary>The update key to apply.</summary>
-        public string UpdateKey { get; set; }
+        /// <summary>The update key to apply (if any).</summary>
+        public string? UpdateKey { get; set; }
 
         /// <summary>The predefined compatibility status.</summary>
         public ModStatus Status { get; set; } = ModStatus.None;
 
         /// <summary>A reason phrase for the <see cref="Status"/>, or <c>null</c> to use the default reason.</summary>
-        public string StatusReasonPhrase { get; set; }
+        public string? StatusReasonPhrase { get; set; }
 
         /// <summary>Technical details shown in TRACE logs for the <see cref="Status"/>, or <c>null</c> to omit it.</summary>
-        public string StatusReasonDetails { get; set; }
+        public string? StatusReasonDetails { get; set; }
 
         /// <summary>The upper version for which the <see cref="Status"/> applies (if any).</summary>
-        public ISemanticVersion StatusUpperVersion { get; set; }
+        public ISemanticVersion? StatusUpperVersion { get; set; }
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="dataRecord">The underlying data record.</param>
+        public ModDataRecordVersionedFields(ModDataRecord dataRecord)
+        {
+            this.DataRecord = dataRecord;
+        }
     }
 }
diff --git a/src/SMAPI.Toolkit/Framework/ModData/ModDatabase.cs b/src/SMAPI.Toolkit/Framework/ModData/ModDatabase.cs
index a5237334..168b8aac 100644
--- a/src/SMAPI.Toolkit/Framework/ModData/ModDatabase.cs
+++ b/src/SMAPI.Toolkit/Framework/ModData/ModDatabase.cs
@@ -1,5 +1,3 @@
-#nullable disable
-
 using System;
 using System.Collections.Generic;
 using System.Linq;
@@ -16,7 +14,7 @@ namespace StardewModdingAPI.Toolkit.Framework.ModData
         private readonly ModDataRecord[] Records;
 
         /// <summary>Get an update URL for an update key (if valid).</summary>
-        private readonly Func<string, string> GetUpdateUrl;
+        private readonly Func<string, string?> GetUpdateUrl;
 
 
         /*********
@@ -29,7 +27,7 @@ namespace StardewModdingAPI.Toolkit.Framework.ModData
         /// <summary>Construct an instance.</summary>
         /// <param name="records">The underlying mod data records indexed by default display name.</param>
         /// <param name="getUpdateUrl">Get an update URL for an update key (if valid).</param>
-        public ModDatabase(IEnumerable<ModDataRecord> records, Func<string, string> getUpdateUrl)
+        public ModDatabase(IEnumerable<ModDataRecord> records, Func<string, string?> getUpdateUrl)
         {
             this.Records = records.ToArray();
             this.GetUpdateUrl = getUpdateUrl;
@@ -43,7 +41,7 @@ namespace StardewModdingAPI.Toolkit.Framework.ModData
 
         /// <summary>Get a mod data record.</summary>
         /// <param name="modID">The unique mod ID.</param>
-        public ModDataRecord Get(string modID)
+        public ModDataRecord? Get(string? modID)
         {
             return !string.IsNullOrWhiteSpace(modID)
                 ? this.Records.FirstOrDefault(p => p.HasID(modID))
@@ -52,11 +50,11 @@ namespace StardewModdingAPI.Toolkit.Framework.ModData
 
         /// <summary>Get the mod page URL for a mod (if available).</summary>
         /// <param name="id">The unique mod ID.</param>
-        public string GetModPageUrlFor(string id)
+        public string? GetModPageUrlFor(string? id)
         {
             // get update key
-            ModDataRecord record = this.Get(id);
-            ModDataField updateKeyField = record?.Fields.FirstOrDefault(p => p.Key == ModDataFieldKey.UpdateKey);
+            ModDataRecord? record = this.Get(id);
+            ModDataField? updateKeyField = record?.Fields.FirstOrDefault(p => p.Key == ModDataFieldKey.UpdateKey);
             if (updateKeyField == null)
                 return null;
 
diff --git a/src/SMAPI.Toolkit/Properties/AssemblyInfo.cs b/src/SMAPI.Toolkit/Properties/AssemblyInfo.cs
index eede4562..6f5dffbe 100644
--- a/src/SMAPI.Toolkit/Properties/AssemblyInfo.cs
+++ b/src/SMAPI.Toolkit/Properties/AssemblyInfo.cs
@@ -2,4 +2,5 @@ using System.Runtime.CompilerServices;
 
 [assembly: InternalsVisibleTo("StardewModdingAPI")]
 [assembly: InternalsVisibleTo("SMAPI.Installer")]
+[assembly: InternalsVisibleTo("SMAPI.Tests")]
 [assembly: InternalsVisibleTo("SMAPI.Web")]
diff --git a/src/SMAPI.Toolkit/Serialization/Models/Manifest.cs b/src/SMAPI.Toolkit/Serialization/Models/Manifest.cs
index 01010602..da3ad608 100644
--- a/src/SMAPI.Toolkit/Serialization/Models/Manifest.cs
+++ b/src/SMAPI.Toolkit/Serialization/Models/Manifest.cs
@@ -46,7 +46,7 @@ namespace StardewModdingAPI.Toolkit.Serialization.Models
 
         /// <summary>Any manifest fields which didn't match a valid field.</summary>
         [JsonExtensionData]
-        public IDictionary<string, object> ExtraFields { get; set; } = new Dictionary<string, object>();
+        public IDictionary<string, object> ExtraFields { get; } = new Dictionary<string, object>();
 
 
         /*********