refactor(audience): enable nullable reference types on Slice 2 files

ImmutableJeffrey · ImmutableJeffrey · commit fd3400784ca6 · 2026-04-22T10:55:38.000+10:00
Applies #nullable enable + targeted `?` annotations per the
HttpTransport precedent (PR 691). Scope: the six files introduced
or substantially modified in Slice 2.

- IEvent.cs: no annotations needed; impl returns non-null.
- IdentityType.cs: ToLowercaseString return → string? (existing
  comment documents null-on-unknown-cast contract).
- TypedEvents.cs: optional properties → string?; also tightens
  IsIso4217 to non-null param (Currency gets an explicit
  null-or-invalid check before dict assignment). Adds a
  Resource.Currency null/empty validation that was missing.
- Core/ConsentStore.cs: no annotations needed.
- Core/Constants.cs: BaseUrl/MessagesUrl/ConsentUrl/DataUrl params
  → string? (code already guards with `publishableKey != null`).
- Events/MessageBuilder.cs: Track/Identify guarded params
  (anonymousId, userId, identityType) → string?; properties/traits
  → Dictionary&lt;string, object&gt;?. Truncate tightened to non-null
  input (callers guard before the call).

Compile-time annotations only. Zero runtime behaviour change
except Resource.Currency now throws on null/empty, matching the
"Required" comment on the field.
diff --git a/src/Packages/Audience/Runtime/Core/ConsentStore.cs b/src/Packages/Audience/Runtime/Core/ConsentStore.cs
@@ -1,3 +1,5 @@
+#nullable enable
+
 using System;
 using System.IO;
 
diff --git a/src/Packages/Audience/Runtime/Core/Constants.cs b/src/Packages/Audience/Runtime/Core/Constants.cs
@@ -1,3 +1,5 @@
+#nullable enable
+
 namespace Immutable.Audience
 {
     internal static class Constants
@@ -23,11 +25,11 @@ internal static class Constants
 
         internal const string PublishableKeyHeader = "x-immutable-publishable-key";
 
-        internal static string MessagesUrl(string publishableKey) => BaseUrl(publishableKey) + MessagesPath;
-        internal static string ConsentUrl(string publishableKey) => BaseUrl(publishableKey) + ConsentPath;
-        internal static string DataUrl(string publishableKey) => BaseUrl(publishableKey) + DataPath;
+        internal static string MessagesUrl(string? publishableKey) => BaseUrl(publishableKey) + MessagesPath;
+        internal static string ConsentUrl(string? publishableKey) => BaseUrl(publishableKey) + ConsentPath;
+        internal static string DataUrl(string? publishableKey) => BaseUrl(publishableKey) + DataPath;
 
-        internal static string BaseUrl(string publishableKey) =>
+        internal static string BaseUrl(string? publishableKey) =>
             publishableKey != null && publishableKey.StartsWith(TestKeyPrefix)
                 ? SandboxBaseUrl
                 : ProductionBaseUrl;
diff --git a/src/Packages/Audience/Runtime/Core/Identity.cs b/src/Packages/Audience/Runtime/Core/Identity.cs
@@ -1,3 +1,5 @@
+#nullable enable
+
 using System;
 using System.IO;
 
@@ -12,13 +14,13 @@ namespace Immutable.Audience
     internal sealed class Identity
     {
         // In-memory cache — volatile so background threads always see the latest write.
-        private static volatile string _cachedId;
+        private static volatile string? _cachedId;
         private static readonly object _sync = new object();
 
         // Returns the existing anonymous ID, or null if none exists. Never
         // creates one — for call sites that must not register a new ID as
         // a side-effect.
-        internal static string Get(string persistentDataPath)
+        internal static string? Get(string persistentDataPath)
         {
             if (_cachedId != null) return _cachedId;
 
@@ -59,7 +61,7 @@ internal static void ClearCache()
         // Returns the anonymous ID, generating and persisting it on first call.
         // Returns null without touching disk when consent is None.
         // Safe to call from any thread after ImmutableAudience.Init() has run on the main thread.
-        internal static string GetOrCreate(string persistentDataPath, ConsentLevel consent)
+        internal static string? GetOrCreate(string persistentDataPath, ConsentLevel consent)
         {
             // No ID until the player grants at least anonymous consent.
             if (consent == ConsentLevel.None)
diff --git a/src/Packages/Audience/Runtime/Events/IEvent.cs b/src/Packages/Audience/Runtime/Events/IEvent.cs
@@ -1,3 +1,5 @@
+#nullable enable
+
 using System.Collections.Generic;
 
 namespace Immutable.Audience
diff --git a/src/Packages/Audience/Runtime/Events/MessageBuilder.cs b/src/Packages/Audience/Runtime/Events/MessageBuilder.cs
@@ -1,3 +1,5 @@
+#nullable enable
+
 using System;
 using System.Collections.Generic;
 
@@ -7,10 +9,10 @@ internal static class MessageBuilder
     {
         internal static Dictionary<string, object> Track(
             string eventName,
-            string anonymousId,
-            string userId,
+            string? anonymousId,
+            string? userId,
             string packageVersion,
-            Dictionary<string, object> properties = null)
+            Dictionary<string, object>? properties = null)
         {
             var msg = BuildBase(MessageTypes.Track, packageVersion);
             msg["eventName"] = Truncate(eventName, Constants.MaxFieldLength);
@@ -22,17 +24,20 @@ internal static Dictionary<string, object> Track(
                 msg[MessageFields.UserId] = Truncate(userId, Constants.MaxFieldLength);
 
             if (properties != null && properties.Count > 0)
+            {
+                TruncateStringValues(properties);
                 msg["properties"] = properties;
+            }
 
             return msg;
         }
 
         internal static Dictionary<string, object> Identify(
-            string anonymousId,
-            string userId,
-            string identityType,
+            string? anonymousId,
+            string? userId,
+            string? identityType,
             string packageVersion,
-            Dictionary<string, object> traits = null)
+            Dictionary<string, object>? traits = null)
         {
             var msg = BuildBase(MessageTypes.Identify, packageVersion);
 
@@ -46,7 +51,10 @@ internal static Dictionary<string, object> Identify(
                 msg["identityType"] = Truncate(identityType, Constants.MaxFieldLength);
 
             if (traits != null && traits.Count > 0)
+            {
+                TruncateStringValues(traits);
                 msg["traits"] = traits;
+            }
 
             return msg;
         }
@@ -84,9 +92,20 @@ private static Dictionary<string, object> BuildBase(string type, string packageV
 
         private static string Truncate(string s, int maxLen)
         {
-            if (s == null || s.Length <= maxLen)
+            if (s.Length <= maxLen)
                 return s;
             return s.Substring(0, maxLen);
         }
+
+        private static void TruncateStringValues(Dictionary<string, object> dict)
+        {
+            // Snapshot keys to avoid mutating the collection during iteration.
+            var keys = new List<string>(dict.Keys);
+            foreach (var key in keys)
+            {
+                if (dict[key] is string s && s.Length > Constants.MaxFieldLength)
+                    dict[key] = Truncate(s, Constants.MaxFieldLength);
+            }
+        }
     }
 }
diff --git a/src/Packages/Audience/Runtime/Events/TypedEvents.cs b/src/Packages/Audience/Runtime/Events/TypedEvents.cs
@@ -1,3 +1,5 @@
+#nullable enable
+
 using System;
 using System.Collections.Generic;
 
@@ -31,9 +33,9 @@ public class Progression : IEvent
         // Required.
         public ProgressionStatus Status { get; set; }
         // Optional.
-        public string World { get; set; }
-        public string Level { get; set; }
-        public string Stage { get; set; }
+        public string? World { get; set; }
+        public string? Level { get; set; }
+        public string? Stage { get; set; }
         public int? Score { get; set; }
         public float? DurationSec { get; set; }
 
@@ -81,16 +83,19 @@ public class Resource : IEvent
     {
         // Required.
         public ResourceFlow Flow { get; set; }
-        public string Currency { get; set; }
+        public string? Currency { get; set; }
         public float Amount { get; set; }
         // Optional.
-        public string ItemType { get; set; }
-        public string ItemId { get; set; }
+        public string? ItemType { get; set; }
+        public string? ItemId { get; set; }
 
         public string EventName => "resource";
 
         public Dictionary<string, object> ToProperties()
         {
+            if (string.IsNullOrEmpty(Currency))
+                throw new ArgumentException("Resource.Currency must not be null or empty");
+
             var props = new Dictionary<string, object>
             {
                 ["flow"] = Flow.ToLowercaseString(),
@@ -109,21 +114,21 @@ public Dictionary<string, object> ToProperties()
     public class Purchase : IEvent
     {
         // Required. ISO 4217 three-letter uppercase currency code.
-        public string Currency { get; set; }
+        public string? Currency { get; set; }
         // Required.
         public decimal Value { get; set; }
         // Optional.
-        public string ItemId { get; set; }
-        public string ItemName { get; set; }
+        public string? ItemId { get; set; }
+        public string? ItemName { get; set; }
         public int? Quantity { get; set; }
-        public string TransactionId { get; set; }
+        public string? TransactionId { get; set; }
 
         public string EventName => "purchase";
 
         // Hand-rolled to avoid pulling System.Text.RegularExpressions into the IL2CPP build.
         private static bool IsIso4217(string s)
         {
-            if (s == null || s.Length != 3) return false;
+            if (s.Length != 3) return false;
             for (var i = 0; i < 3; i++)
             {
                 var c = s[i];
@@ -134,7 +139,7 @@ private static bool IsIso4217(string s)
 
         public Dictionary<string, object> ToProperties()
         {
-            if (!IsIso4217(Currency))
+            if (Currency == null || !IsIso4217(Currency))
                 throw new ArgumentException(
                     $"Purchase.Currency '{Currency}' must be a three-letter uppercase ISO 4217 code");
 
@@ -157,7 +162,7 @@ public Dictionary<string, object> ToProperties()
     public class MilestoneReached : IEvent
     {
         // Required.
-        public string Name { get; set; }
+        public string? Name { get; set; }
 
         public string EventName => "milestone_reached";
 
diff --git a/src/Packages/Audience/Runtime/IdentityType.cs b/src/Packages/Audience/Runtime/IdentityType.cs
@@ -1,3 +1,5 @@
+#nullable enable
+
 namespace Immutable.Audience
 {
     // Identity provider accepted by the Audience backend.
@@ -18,7 +20,7 @@ internal static class IdentityTypeExtensions
         // Returns null on unknown casts. The string overloads of Identify /
         // Alias check for null/empty and drop + warn, so an out-of-range
         // cast surfaces as a dropped event, not a corrupt wire payload.
-        internal static string ToLowercaseString(this IdentityType type) => type switch
+        internal static string? ToLowercaseString(this IdentityType type) => type switch
         {
             IdentityType.Passport => "passport",
             IdentityType.Steam => "steam",

Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,5 @@`
	`1`	`+#nullable enable`
	`2`	`+`
`1`	`3`	`using System;`
`2`	`4`	`using System.IO;`
`3`	`5`
Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,5 @@`
	`1`	`+#nullable enable`
	`2`	`+`
`1`	`3`	`using System.Collections.Generic;`
`2`	`4`
`3`	`5`	`namespace Immutable.Audience`