System.NullReferenceException: Object reference not set to an instance of an object

[Lexicality]

When my project starts I get this in the output window

Starting Microsoft Python language server.
Initializing for c:\Users\lexro\projects\partner-stats\.venv\Scripts\python.exe
Loading files from c:\Users\lexro\projects\partner-stats
Parsing document file:///c:/Users/lexro/projects/partner-stats/setup.py
Parse complete for file:///c:/Users/lexro/projects/partner-stats/setup.py at version -1
Analysis queued for file:///c:/Users/lexro/projects/partner-stats/setup.py
Waiting for parsing to complete.
Parsing complete. Waiting for analysis entries to enqueue.
##########Linting Output - mypy##########
##########Linting Output - flake8##########
Enqueue complete. Waiting for analysis to complete.
[Error - 12:15:03 AM] System.NullReferenceException: Object reference not set to an instance of an object.
   at Microsoft.PythonTools.Interpreter.Ast.AstPythonInterpreter.ImportModule(String name)
   at Microsoft.PythonTools.Analysis.ModuleTable.TryImport(String name, ModuleReference& res)
   at Microsoft.PythonTools.Analysis.Analyzer.DDG.TryImportModule(String modName, Boolean forceAbsolute, ModuleReference& moduleRef, IReadOnlyList`1& remainingParts)
   at Microsoft.PythonTools.Analysis.Analyzer.DDG.Walk(FromImportStatement node)
   at Microsoft.PythonTools.Parsing.Ast.FromImportStatement.Walk(PythonWalker walker)
   at Microsoft.PythonTools.Analysis.Analyzer.DDG.Walk(SuiteStatement node)
   at Microsoft.PythonTools.Parsing.Ast.SuiteStatement.Walk(PythonWalker walker)
   at Microsoft.PythonTools.Parsing.Ast.PythonAst.Walk(PythonWalker walker)
   at Microsoft.PythonTools.Analysis.AnalysisUnit.AnalyzeWorker(DDG ddg, CancellationToken cancel)
   at Microsoft.PythonTools.Analysis.Analyzer.DDG.Analyze(Deque`1 queue, CancellationToken cancel, Action`1 reportQueueSize, Int32 reportQueueInterval)
   at Microsoft.PythonTools.Analysis.PythonAnalyzer.AnalyzeQueuedEntries(CancellationToken cancel)
   at Microsoft.PythonTools.Intellisense.AnalysisQueue.GroupAnalysis.Analyze(CancellationToken cancel)
   at Microsoft.PythonTools.Intellisense.AnalysisQueue.HandleAnalyzable(IAnalyzable item, AnalysisPriority priority, CancellationToken cancellationToken)
   at Microsoft.PythonTools.Intellisense.AnalysisQueue.ConsumerLoop()

Then I get this error once for every file in the project:

Parsing document file:///c:/Users/lexro/projects/partner-stats/src/partner_stats/es_helper.py
Parse complete for file:///c:/Users/lexro/projects/partner-stats/src/partner_stats/es_helper.py at version -1
Analysis queued for file:///c:/Users/lexro/projects/partner-stats/src/partner_stats/es_helper.py
Waiting for parsing to complete.
Parsing complete. Waiting for analysis entries to enqueue.
[Error - 12:15:04 AM] System.ObjectDisposedException: PriorityProducerConsumer`1 instance is disposed
Object name: 'PriorityProducerConsumer`1'.
   at Microsoft.PythonTools.Analysis.Infrastructure.DisposeToken.ThrowIfDisposed()
   at Microsoft.PythonTools.Analysis.Infrastructure.PriorityProducerConsumer`1.Produce(T value, Int32 priority)
   at Microsoft.PythonTools.Intellisense.AnalysisQueue.Enqueue(IAnalyzable item, AnalysisPriority priority)
   at Microsoft.Python.LanguageServer.Implementation.Server.OnDocumentChangeProcessingCompleteAsync(IDocument doc, VersionCookie vc, Boolean enqueueForAnalysis, AnalysisPriority priority, IDisposable disposeWhenEnqueued)
Enqueue complete. Waiting for analysis to complete.

after which I get something along the lines of this error every time I hover over something

Waiting for parsing to complete.
Parsing complete. Waiting for analysis entries to enqueue.
Enqueue complete. Waiting for analysis to complete.
[Error - 12:15:05 AM] Request textDocument/documentSymbol failed.
  Message: PriorityProducerConsumer`1 instance is disposed
Object name: 'PriorityProducerConsumer`1'.
  Code: -32000 
[object Object]

This is with the loglevel set to trace.
I'm using Python 3.6.5 under a virtualenv on x64 Windows 10 Pro v1803, with the latest version of the language server that the non-insiders build of vscode (1.27.2) dowloads.

[MikhailArkhipov]

#68
#72

Fixed in upcoming release

[Lexicality]

Ah, sorry.

[Lexicality]

Is there somewhere I can subscribe to in order to know when releases happen?

[MikhailArkhipov]

@Lexicality - we are changing the extension so it will download new bits automatically. However, if you are on a stable train, you may not see updates as often as on beta or daily trains. See microsoft/vscode-python#2676 and microsoft/vscode-python#2580

[Lexicality]

I can't see any references to trains, but it downloadedPython-Language-Server-win-x86.beta.nupkg which implies beta I guess?
Also, I have had to fall back to Jedi so I can work, will the language server update itself when not enabled?

[MikhailArkhipov]

Yes, there are 'stable' (ie release), 'beta' (insiders) and 'daily'. I believe current beta is reported as 0.1.37 or so. I don't think you see them yet, this is for the upcoming release.