Envelopes with oversized attachments getting stuck in __processing (Possible regression)

[jamescrosswell]

Originally posted by @jamescrosswell in #3792

macOS

On macOS, the following code results in a java.net.SocketException: Socket closed exception when processing the envelope:

.UseSentry(options =>
{
                // All the standard options
                const int mb = 1024 * 1024;
                options.MaxAttachmentSize = 80 * mb;
                options.SetBeforeSend((e, h) =>
                {
                    var random = new Random();
                    var byteArray = new byte[20 * mb];
                    random.NextBytes(byteArray);

                    h.AddAttachment(byteArray, $"twentymb.bin");

                    return e;
                });
}

Additionally, the envelope getting stuck in the __processing directory and preventing other envelopes from being sent. I think that is a problem in the .NET SDK and possibly a regression of:

• Envelopes stuck in __processing until restart #3384

[jamescrosswell]

When attempting to send these envelopes, because the server is simply disconnecting, the client SDK is executing this logic (try again when the network is "back online"):

sentry-dotnet/src/Sentry/Internal/Http/CachingTransport.cs

Lines 349 to 358 in f2ca96c

	catch (Exception ex) when (IsNetworkError(ex))
	{
	if (_options.NetworkStatusListener is PollingNetworkStatusListener pollingListener)
	{
	pollingListener.Online = false;
	}
	_options.LogError(ex, "Failed to send cached envelope: {0}, retrying after a delay.", file);
	// Let the worker catch, log, wait a bit and retry.
	throw;
	}

Instead of this logic (fail and log):

sentry-dotnet/src/Sentry/Internal/Http/CachingTransport.cs

Lines 364 to 368 in f2ca96c

	catch (Exception ex)
	{
	_options.ClientReportRecorder.RecordDiscardedEvents(DiscardReason.CacheOverflow, envelope);
	LogFailureWithDiscard(file, ex);
	}

The IsNetworkError method is overly simplistic:

sentry-dotnet/src/Sentry/Internal/Http/CachingTransport.cs

Lines 303 to 308 in f2ca96c

	private static bool IsNetworkError(Exception exception) =>
	exception switch
	{
	HttpRequestException or WebException or IOException or SocketException => true,
	_ => false
	};

In the case of Broken Pipe or Connection Reset by Peer socket exceptions, we should probably assume the connection was reset intentionally by the remote host and fail/discard these envelopes.