When using RX 2 Contract Assemblies from the RXX project, Static Analyzer doesn't seem to understand contracts on the observable creation methods
Tuesday, February 05, 2013 4:33 PM
When I use methods such as:IObservable<T> Observable.Create<T>(Func<IObserver<T>,IDisposable>);
The Analyzer cannot prove that their return value is not NULL, even though in the contract assembly they have a contract.Ensures on them:public static IObservable<TValue> Defer<TValue>(Func<IObservable<TValue>> observableFactory)
Contract.Requires(observableFactory != null, null, "observableFactory != null");
Contract.Ensures(Contract.Result<IObservable<TValue>>() != null, null, "Contract.Result<IObservable<TValue>>() != null");
Here are some examples:
"ensures unproven: Contract.Result<IObservable<object>>() != null"private IObservable<object> ExecuteObservableService<TRequestDto, TResponseDto>(TRequestDto request)
where TResponseDto : class, IObservable<object>
where TRequestDto : class
Contract.Requires(request != null);
Contract.Ensures(Contract.Result<IObservable<object>>() != null);
return Observable.Using(_serviceFactory.GetService<TRequestDto, TResponseDto>, service => service.Instance.Execute(request));
"ensures unproven: Contract.Result<IObservable<ProjectorResult>>() != null"/// <inheritdoc/>
public IObservable<ProjectorResult> Project(IProjector projectors, Func<long, IObservable<Commit>> queryCommits)
return Observable.Create<ProjectorResult>(observer => ProjectionistObservable(observer, projectors, queryCommits));
"requires unproven: source != null" (it is complaining about the "Requires" rule for the .Where operator)return Observable
.Defer(async () => _zookeeperClient.WatchData(await GetJobPathAsync(request.WorkflowId, request.JobId).NoContext()))
.Where(data => data != null && data.Count() >= 8)
The last example proves that the analyzer is using the contract assembly (since it is complaining about a Requires within the Where method.
Any ideas how to fix this?
Tuesday, February 05, 2013 8:36 PM
I've run into the same problem as well. It's one of the reasons that I never published the contract assemblies for Rx 2.0 as a separate download.
I assume the issue has something to do with the fact that I created the contract assemblies by hand. There must be some subtle difference between these assemblies and contract assemblies that are generated by the CC tools. The contract assemblies that I had created for Rx 1.0 worked fine. I combed over the new contract assemblies carefully, comparing them to existing contract assemblies that ship with CC, but I couldn't find any obvious differences. I tried several small adjustments to match the attributes in FCL contract assemblies, but nothing has worked.
The issue may go away once I add the contracts directly to the Rx library and let CC generate contract assemblies from the source, but it's only a work-in-progress:
Note that I've actually made some progress already, I just haven't checked it in yet.