Language service fails when using Python 2.7 interpreter

[DonJayamanne]

• Open a workspace with Python code
• Select Python 2.7 interpreter
• Error message is displayed, see below

@MikhailArkhipov

[MikhailArkhipov]

Specific Python? Works on Windows & Ubuntu. Might be threading issue - is it consistent when you flip between interpreters? If you can, attach to dotnet.exe from VSC (.NET Core Attach in C# extension), as in https://github.com/Microsoft/vscode-python/blob/master/CONTRIBUTING%20-%20PYTHON_ANALYSIS.md#debugging-c-code-in-python-analysis-engine.

[patrys]

I have a project (under an NDA unfortunately) where I can trigger this with 100% success (or, should I say, 100% failure). I'll try to isolate a package that triggers it or trace the ptvs code if time permits.

[DonJayamanne]

If you can, attach to dotnet.exe from VSC (.NET Core Attach in C# extension), as in /CONTRIBUTING%20-%20PYTHON_ANALYSIS.md@master#debugging-c-code-in-python-analysis-engine.

todo @DonJayamanne

[MilkyHearts]

Works prefect in Python3 but not 2.7 >.<

[patrys]

JS stack trace

Object reference not set to an instance of an object.: Error: Object reference not set to an instance of an object.
    at new ResponseError (/Users/patrys/.vscode-insiders/extensions/ms-python.python-2018.6.0/node_modules/vscode-jsonrpc/lib/messages.js:46:28)
    at handleResponse (/Users/patrys/.vscode-insiders/extensions/ms-python.python-2018.6.0/node_modules/vscode-jsonrpc/lib/main.js:430:48)
    at processMessageQueue (/Users/patrys/.vscode-insiders/extensions/ms-python.python-2018.6.0/node_modules/vscode-jsonrpc/lib/main.js:258:17)
    at Immediate.<anonymous> (/Users/patrys/.vscode-insiders/extensions/ms-python.python-2018.6.0/node_modules/vscode-jsonrpc/lib/main.js:242:13)
    at runCallback (timers.js:672:20)
    at tryOnImmediate (timers.js:645:5)
    at processImmediate [as _immediateCallback] (timers.js:617:5)

Value cannot be null.
Parameter name: type: Error: Value cannot be null.
Parameter name: type
    at new ResponseError (/Users/patrys/.vscode-insiders/extensions/ms-python.python-2018.6.0/node_modules/vscode-jsonrpc/lib/messages.js:46:28)
    at handleResponse (/Users/patrys/.vscode-insiders/extensions/ms-python.python-2018.6.0/node_modules/vscode-jsonrpc/lib/main.js:430:48)
    at processMessageQueue (/Users/patrys/.vscode-insiders/extensions/ms-python.python-2018.6.0/node_modules/vscode-jsonrpc/lib/main.js:258:17)
    at Immediate.<anonymous> (/Users/patrys/.vscode-insiders/extensions/ms-python.python-2018.6.0/node_modules/vscode-jsonrpc/lib/main.js:242:13)
    at runCallback (timers.js:672:20)
    at tryOnImmediate (timers.js:645:5)
    at processImmediate [as _immediateCallback] (timers.js:617:5)

[DonJayamanne]

@MikhailArkhipov Does this work on Python 2.7 for you?

[patrys]

C# stack trace

[Error - 12:45:42] System.NullReferenceException: Object reference not set to an instance of an object.
   at Microsoft.PythonTools.Analysis.Values.BuiltinNamespace`1.Equals(Object obj)
   at System.Linq.Enumerable.All[TSource](IEnumerable`1 source, Func`2 predicate)
   at Microsoft.PythonTools.Analysis.AnalysisValue.Microsoft.PythonTools.Analysis.IAnalysisSet.Union(IEnumerable`1 items, Boolean canMutate)
   at Microsoft.PythonTools.Analysis.AnalysisValueSetExtensions.GetMember(IAnalysisSet self, Node node, AnalysisUnit unit, String name)
   at Microsoft.PythonTools.Analysis.Values.LazyValueInfo.ResolveOnce(AnalysisUnit unit, ResolutionContext context, Boolean& cacheResult)
   at Microsoft.PythonTools.Analysis.Values.LazyValueInfo.Resolve(AnalysisUnit unit, ResolutionContext context)
   at Microsoft.PythonTools.Analysis.AnalysisValueSetExtensions.Resolve(IAnalysisSet self, AnalysisUnit unit, ResolutionContext context, Boolean& changed)
   at Microsoft.PythonTools.Analysis.Values.LazyValueInfo.Resolve(AnalysisUnit unit, ResolutionContext context)
   at Microsoft.PythonTools.Analysis.AnalysisValueSetExtensions.Resolve(IAnalysisSet self, AnalysisUnit unit, ResolutionContext context, Boolean& changed)
   at Microsoft.PythonTools.Analysis.Analyzer.ExpressionEvaluator.AssignTo(Node assignStmt, Expression left, IAnalysisSet values)
   at Microsoft.PythonTools.Analysis.Analyzer.DDG.Walk(AssignmentStatement node)
   at Microsoft.PythonTools.Parsing.Ast.AssignmentStatement.Walk(PythonWalker walker)
   at Microsoft.PythonTools.Analysis.Analyzer.DDG.Walk(SuiteStatement node)
   at Microsoft.PythonTools.Parsing.Ast.SuiteStatement.Walk(PythonWalker walker)
   at Microsoft.PythonTools.Analysis.Analyzer.DDG.Walk(TryStatement node)
   at Microsoft.PythonTools.Parsing.Ast.TryStatement.Walk(PythonWalker walker)
   at Microsoft.PythonTools.Analysis.Analyzer.DDG.Walk(SuiteStatement node)
   at Microsoft.PythonTools.Parsing.Ast.SuiteStatement.Walk(PythonWalker walker)
   at Microsoft.PythonTools.Analysis.Analyzer.FunctionAnalysisUnit.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.Worker(Object threadStarted)