[BUG]: DateTimeOffsetConverter doesn't parse null completed_at

[itrion]

What happened?

Similartly to #140, the DateTimeOffsetConverter is throwing

System.Text.Json.JsonException
'Null' is not an allowed token type for the DateTimeOffsetConverter
   at Octokit.Webhooks.Converter.DateTimeOffsetConverter.ReadInternal(Utf8JsonReader& reader)
   at Octokit.Webhooks.Converter.DateTimeOffsetConverter.Read(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options)
...

when parsing a workflow_job event with several "completed_at": null. The completed_at with null values are in

• .workflow_job.completed_at
• and .workflow_job.steps[N].completed_at

Versions

Octokit.Webhooks.AspNetCore 2.4.0

Relevant log output

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

[github-actions]

👋 Hi! Thank you for this contribution! Just to let you know, our GitHub SDK team does a round of issue and PR reviews twice a week, every Monday and Friday! We have a process in place for prioritizing and responding to your input. Because you are a part of this community please feel free to comment, add to, or pick up any issues/PRs that are labeled with Status: Up for grabs. You & others like you are the reason all of this works! So thank you & happy coding! 🚀

[JamieMagee]

@itrion do you have a sample payload that I can test with? It looks like workflow_job.completed_at is already nullable (though it's string? instead of DateTimeOffset?)

webhooks.net/src/Octokit.Webhooks/Models/WorkflowJobEvent/WorkflowJob.cs

Lines 66 to 67 in ecab931

	[JsonPropertyName("completed_at")]
	public string? CompletedAt { get; init; }

And workflow_job.steps[].completed_at is already DateTimeOffset? and uses the NullableDateTimeOffsetConverter

webhooks.net/src/Octokit.Webhooks/Models/WorkflowJobEvent/WorkflowJobStep.cs

Lines 24 to 26 in ecab931

	[JsonPropertyName("completed_at")]
	[JsonConverter(typeof(NullableDateTimeOffsetConverter))]
	public DateTimeOffset? CompletedAt { get; init; }

[itrion]

Thank you @JamieMagee, after a deeper troubleshooting I realized it was actually failing parsing the started_at. Let me know if you need a full payload or if this is enough

{
	"action": "in_progress",
	"workflow_job": {
		"id": 123,
		"run_id": 1234,
		"workflow_name": "docker in  - Update",
		"head_branch": "main",
		"run_url": "https://api.github.com/repos/example/example/actions/runs/11439205892",
		"run_attempt": 1,
		"node_id": "CR_123",
		"head_sha": "96bd5bd7ac9cbc35a15cea8262abbd385778342b",
		"url": "https://api.github.com/repos/example/example/actions/jobs/31822394947",
		"html_url": "https://github.com/example/example/actions/runs/11439205892/job/31822394947",
		"status": "in_progress",
		"conclusion": null,
		"created_at": "2024-10-21T11:32:36Z",
		"started_at": "2024-10-21T11:32:47Z",
		"completed_at": null,
		"name": "Dependabot",
		"steps": [
			{
				"name": "Set up job",
				"status": "completed",
				"conclusion": "success",
				"number": 1,
				"started_at": "2024-10-21T11:32:47Z",
				"completed_at": "2024-10-21T11:32:48Z"
			},
			{
				"name": "Verify actions runner dependencies",
				"status": "in_progress",
				"conclusion": null,
				"number": 2,
				"started_at": "2024-10-21T11:32:48Z",
				"completed_at": null
			},
			{
				"name": "Create job directory",
				"status": "pending",
				"conclusion": null,
				"number": 3,
				"started_at": null,
				"completed_at": null
			},
			{
				"name": "Run Dependabot",
				"status": "pending",
				"conclusion": null,
				"number": 4,
				"started_at": null,
				"completed_at": null
			},
			{
				"name": "Cleanup job directory",
				"status": "pending",
				"conclusion": null,
				"number": 5,
				"started_at": null,
				"completed_at": null
			}
		],
		"check_run_url": "https://api.github.com/repos/example/example/check-runs/31822394947",
		"labels": [
			"dependabot"
		],
		"runner_id": 123,
		"runner_name": "dependabot",
		"runner_group_id": 25,
		"runner_group_name": "1234"
	}
}

I got to reproduce it with that payload running

	[Fact]
	public async Task ReproduceError()
	{
		var payload = await File.ReadAllTextAsync($"Fixtures/test-github-webhook-workflow_job-null-issue.json");
		var workflowJobEvent = JsonSerializer.Deserialize<WorkflowJobEvent>(payload)!;
		workflowJobEvent.Should().NotBeNull();
	}

[JamieMagee]

Thank you! This should be resolved by #596