Make Member.ExpiresAt tolerant of unparseable expiry dates

src/GitLabApiClient/GitLabApiClient.csproj

@@ -4,7 +4,7 @@
     <TargetFramework>net8.0</TargetFramework>
     <LangVersion>10</LangVersion>
     <PackageId>Apiiro.GitLabApiClient</PackageId>
-    <Version>0.1.44</Version>
+    <Version>0.1.46</Version>
     <Authors>Apiiro</Authors>
     <Company>Apiiro</Company>
     <PackageDescription>GitLabApiClient</PackageDescription>

src/GitLabApiClient/Internal/Http/Serialization/TolerantNullableDateTimeConverter.cs

@@ -0,0 +1,41 @@
+using System;
+using System.Globalization;
+using Newtonsoft.Json;
+
+namespace GitLabApiClient.Internal.Http.Serialization
+{
+    internal sealed class TolerantNullableDateTimeConverter : JsonConverter
+    {
+        public override bool CanConvert(Type objectType) =>
+            objectType == typeof(DateTime?) || objectType == typeof(DateTime);
+
+        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
+        {
+            switch (reader.TokenType)
+            {
+                case JsonToken.Null:
+                    return null;
+                case JsonToken.Date:
+                    return reader.Value is DateTime dateTime ? dateTime : (DateTime?)null;
+                case JsonToken.String:
+                    return DateTime.TryParse((string)reader.Value, CultureInfo.InvariantCulture, DateTimeStyles.None, out var parsed)
+                        ? parsed
+                        : (DateTime?)null;
+                default:
+                    return null;
+            }
+        }
+
+        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
+        {
+            if (value is DateTime dateTime)
+            {
+                writer.WriteValue(dateTime);
+            }
+            else
+            {
+                writer.WriteNull();
+            }
+        }
+    }
+}

src/GitLabApiClient/Models/Member.cs

@@ -1,4 +1,5 @@
 using System;
+using GitLabApiClient.Internal.Http.Serialization;
 using Newtonsoft.Json;
 
 namespace GitLabApiClient.Models
@@ -9,6 +10,7 @@ public sealed class Member : Account
         public int AccessLevel { get; set; }
 
         [JsonProperty("expires_at")]
-        public DateTime ExpiresAt { get; set; }
+        [JsonConverter(typeof(TolerantNullableDateTimeConverter))]
+        public DateTime? ExpiresAt { get; set; }
     }
 }

test/GitLabApiClient.Test/Internal/MemberExpiresAtTest.cs

@@ -0,0 +1,58 @@
+using System;
+using System.Collections.Generic;
+using FluentAssertions;
+using GitLabApiClient.Models;
+using Newtonsoft.Json;
+using Xunit;
+
+namespace GitLabApiClient.Test.Internal
+{
+    public class MemberExpiresAtTest
+    {
+        [Fact]
+        public void UnparseableExpiresAt_YieldsNull_AndRestOfListStillDeserializes()
+        {
+            const string json = @"[
+                { ""id"": 1, ""username"": ""valid"", ""access_level"": 30, ""expires_at"": ""2025-12-04"" },
+                { ""id"": 2, ""username"": ""broken"", ""access_level"": 40, ""expires_at"": ""20235-12-04"" }
+            ]";
+
+            var members = JsonConvert.DeserializeObject<IList<Member>>(json);
+
+            members.Should().HaveCount(2);
+            members[0].ExpiresAt.Should().Be(new DateTime(2025, 12, 4));
+            members[1].Username.Should().Be("broken");
+            members[1].ExpiresAt.Should().BeNull();
+        }
+
+        [Fact]
+        public void NullExpiresAt_YieldsNull()
+        {
+            const string json = @"{ ""id"": 1, ""access_level"": 30, ""expires_at"": null }";
+
+            var member = JsonConvert.DeserializeObject<Member>(json);
+
+            member.ExpiresAt.Should().BeNull();
+        }
+
+        [Fact]
+        public void MissingExpiresAt_YieldsNull()
+        {
+            const string json = @"{ ""id"": 1, ""access_level"": 30 }";
+
+            var member = JsonConvert.DeserializeObject<Member>(json);
+
+            member.ExpiresAt.Should().BeNull();
+        }
+
+        [Fact]
+        public void ValidExpiresAt_IsParsed()
+        {
+            const string json = @"{ ""id"": 1, ""access_level"": 30, ""expires_at"": ""2025-12-04"" }";
+
+            var member = JsonConvert.DeserializeObject<Member>(json);
+
+            member.ExpiresAt.Should().Be(new DateTime(2025, 12, 4));
+        }
+    }
+}