No output in output window when debug in Python 2.7 with "Windows Application" option checked.

[linette-zyy]

Steps to Reproduce

1. Create Python Application project and type code
2. Right-click on the project and select Properties or press Alt+Enter to open Property page
3. Turn on the option "Windows Application" and change interpreter to Python2.7 in General tab and save
4. Start the debugger

Expected behavior
The code runs and can be debugged, and no terminal/console window appears.

Actural behavior
No output in output window.

Debug Host Log

 1> DebugAdapterHost version: 16.6.40221.2 commit:b531e661bd58f91bfddf99f3bb337cf95e9139cd
 1> Starting 'C:\Python27\pythonw.exe' with arguments '"c:\program files (x86)\microsoft visual studio\2019\preview\common7\ide\extensions\microsoft\python\core\debugpy\adapter"'
 1> [DebugAdapter] --> C (initialize-1): {"type":"request","command":"initialize","arguments":{"pathFormat":"path","clientID":"visualstudio","clientName":"Visual Studio","adapterID":null,"locale":"en-US","linesStartAt1":true,"columnsStartAt1":true,"supportsVariableType":true,"supportsRunInTerminalRequest":true,"supportsMemoryReferences":true,"supportsHandshakeRequest":true},"seq":1}
 1> [DebugAdapter] <--   E (output): {"seq": 1, "type": "event", "event": "output", "body": {"category": "telemetry", "output": "ptvsd", "data": {"packageVersion": "1.0.0b1"}}}
 1> [DebugAdapter] <--   E (output): {"seq": 2, "type": "event", "event": "output", "body": {"category": "telemetry", "output": "debugpy", "data": {"packageVersion": "1.0.0b1"}}}
 1> [DebugAdapter] <--   R (initialize-1) [160 ms]: {"seq": 3, "type": "response", "request_seq": 1, "success": true, "command": "initialize", "body": {"supportsModulesRequest": true, "supportsConfigurationDoneRequest": true, "supportsDelayedStackTraceLoading": true, "supportsDebuggerProperties": true, "supportsHitConditionalBreakpoints": true, "supportsSetExpression": true, "supportsGotoTargetsRequest": true, "supportsSetVariable": true, "supportsLogPoints": true, "supportsCompletionsRequest": true, "exceptionBreakpointFilters": [{"filter": "raised", "default": false, "label": "Raised Exceptions"}, {"filter": "uncaught", "default": true, "label": "Uncaught Exceptions"}], "supportsExceptionInfoRequest": true, "supportsValueFormattingOptions": true, "supportsEvaluateForHovers": true, "supportsExceptionOptions": true, "supportsTerminateDebuggee": true, "supportsConditionalBreakpoints": true}}
 1> [DebugAdapter] --> C (launch-2): {"type":"request","command":"launch","arguments":{"noDebug":false,"cwd":"C:\\Users\\vyizh12\\source\\repos\\PythonApplication7\\PythonApplication7\\","python":["C:\\Python27\\pythonw.exe"],"console":"externalTerminal","program":["C:\\Users\\vyizh12\\source\\repos\\PythonApplication7\\PythonApplication7\\PythonApplication7.py"],"django":false,"stopOnEntry":true,"promptBeforeRunningWithBuildError":true,"redirectOutput":true,"waitOnAbnormalExit":true,"waitOnNormalExit":true,"breakOnSystemExitZero":false,"debugStdLib":false,"showReturnValue":true,"env":{"PROCESSOR_ARCHITEW6432":"AMD64","DriverData":"C:\\Windows\\System32\\Drivers\\DriverData","COMPUTERNAME":"vyizh12003","CommonProgramFiles(x86)":"C:\\Program Files (x86)\\Common Files","OneDrive":"C:\\Users\\vyizh12\\OneDrive","HOMEPATH":"\\Users\\vyizh12","VisualStudioEdition":"Microsoft Visual Studio Enterprise 2019","_PTVS_PID":"2704","ServiceHubLogSessionKey":"2CFCAEDC","PROCESSOR_REVISION":"5504","ThreadedWaitDialogDpiContext":"-4","PkgDefApplicationConfigFile":"C:\\Users\\vyizh12\\AppData\\Local\\Microsoft\\VisualStudio\\16.0_c48adc13\\devenv.exe.config","PATHEXT":".COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC","TMP":"C:\\Users\\vyizh12\\AppData\\Local\\Temp","TEMP":"C:\\Users\\vyizh12\\AppData\\Local\\Temp","LOCALAPPDATA":"C:\\Users\\vyizh12\\AppData\\Local","PUBLIC":"C:\\Users\\Public","VSAPPIDNAME":"devenv.exe","CLIENTNAME":"DESKTOP-LF4LRSH","USERDOMAIN":"vyizh12003","ProgramFiles(x86)":"C:\\Program Files (x86)","Path":"C:\\Windows\\system32;C:\\Windows;C:\\Windows\\System32\\Wbem;C:\\Windows\\System32\\WindowsPowerShell\\v1.0\\;C:\\Windows\\System32\\OpenSSH\\;C:\\Program Files\\dotnet\\;C:\\Program Files\\Microsoft SQL Server\\130\\Tools\\Binn\\;C:\\Users\\vyizh12\\AppData\\Local\\Microsoft\\WindowsApps;","PROCESSOR_LEVEL":"6","PROCESSOR_IDENTIFIER":"Intel64 Family 6 Model 85 Stepping 4, GenuineIntel","PSModulePath":"C:\\Program Files\\WindowsPowerShell\\Modules;C:\\Windows\\system32\\WindowsPowerShell\\v1.0\\Modules;C:\\Program Files\\Microsoft Monitoring Agent\\Agent\\PowerShell\\","NUMBER_OF_PROCESSORS":"4","FPS_BROWSER_USER_PROFILE_STRING":"Default","CommonProgramFiles":"C:\\Program Files (x86)\\Common Files","VisualStudioDir":"C:\\Users\\vyizh12\\Documents\\Visual Studio 2019","ProgramData":"C:\\ProgramData","ProgramW6432":"C:\\Program Files","ProgramFiles":"C:\\Program Files (x86)","VSSKUEDITION":"Enterprise","SystemRoot":"C:\\Windows","VSAPPIDDIR":"C:\\Program Files (x86)\\Microsoft Visual Studio\\2019\\Preview\\Common7\\IDE\\","SESSIONNAME":"RDP-Tcp#2","VisualStudioVersion":"16.0","CommonProgramW6432":"C:\\Program Files\\Common Files","LOGONSERVER":"\\\\vyizh12003","USERPROFILE":"C:\\Users\\vyizh12","MSBuildLoadMicrosoftTargetsReadOnly":"true","VSLANG":"1033","USERDOMAIN_ROAMINGPROFILE":"vyizh12003","APPDATA":"C:\\Users\\vyizh12\\AppData\\Roaming","HOMEDRIVE":"C:","USERNAME":"vyizh12","PYTHONPATH":"C:\\Users\\vyizh12\\source\\repos\\PythonApplication7\\PythonApplication7\\","FPS_BROWSER_APP_PROFILE_STRING":"Internet Explorer","PROCESSOR_ARCHITECTURE":"x86","OS":"Windows_NT","ComSpec":"C:\\Windows\\system32\\cmd.exe","SystemDrive":"C:","windir":"C:\\Windows","ALLUSERSPROFILE":"C:\\ProgramData"},"rules":[{"path":"c:\\program files (x86)\\microsoft visual studio\\2019\\preview\\common7\\ide\\extensions\\microsoft\\python\\core\\","include":false}]},"seq":2}
 1> [DebugAdapter] <--   C (runInTerminal-4): {"seq": 4, "type": "request", "command": "runInTerminal", "arguments": {"kind": "external", "args": ["C:\\Python27\\pythonw.exe", "c:\\program files (x86)\\microsoft visual studio\\2019\\preview\\common7\\ide\\extensions\\microsoft\\python\\core\\debugpy\\launcher", "C:\\Users\\vyizh12\\source\\repos\\PythonApplication7\\PythonApplication7\\PythonApplication7.py"], "env": {"DEBUGPY_LAUNCHER_PORT": "50787"}, "title": "Python Debug Console"}}
 1> [DebugAdapter] --> R (runInTerminal-4): {"type":"response","request_seq":4,"success":true,"command":"runInTerminal","body":{"processId":1160},"seq":3}
 1> [DebugAdapter] <--   E (initialized): {"seq": 5, "type": "event", "event": "initialized"}
 1> [DebugAdapter] --> C (setDebuggerProperty-4): {"type":"request","command":"setDebuggerProperty","arguments":{"AllowOutOfProcessSymbols":1},"seq":4}
 1> [DebugAdapter] --> C (setDebuggerProperty-5): {"type":"request","command":"setDebuggerProperty","arguments":{"DisableJITOptimization":0},"seq":5}
 1> [DebugAdapter] --> C (setDebuggerProperty-6): {"type":"request","command":"setDebuggerProperty","arguments":{"EnableFastEvaluate":1},"seq":6}
 1> [DebugAdapter] --> C (setDebuggerProperty-7): {"type":"request","command":"setDebuggerProperty","arguments":{"InterpreterOptions":1},"seq":7}
 1> [DebugAdapter] --> C (setDebuggerProperty-8): {"type":"request","command":"setDebuggerProperty","arguments":{"JustMyCodeStepping":1},"seq":8}
 1> [DebugAdapter] --> C (setDebuggerProperty-9): {"type":"request","command":"setDebuggerProperty","arguments":{"StopOnExceptionCrossingManagedBoundary":0},"seq":9}
 1> [DebugAdapter] --> C (setDebuggerProperty-10): {"type":"request","command":"setDebuggerProperty","arguments":{"WarnIfNoUserCodeOnLaunch":1},"seq":10}
 1> [DebugAdapter] --> C (setDebuggerProperty-11): {"type":"request","command":"setDebuggerProperty","arguments":{"EnableStepFiltering":true},"seq":11}
 1> [DebugAdapter] --> C (setExceptionBreakpoints-12): {"type":"request","command":"setExceptionBreakpoints","arguments":{"filters":[],"exceptionOptions":[{"breakMode":"userUnhandled","path":[{"names":["Python Exceptions"]}]},{"breakMode":"unhandled","path":[{"names":["Python Exceptions"]},{"names":["GeneratorExit","IndexError","StopIteration","AttributeError","KeyError"]}]}]},"seq":12}
 1> [DebugAdapter] <--   R (setDebuggerProperty-4) [20 ms]: {"seq": 6, "type": "response", "request_seq": 4, "success": true, "command": "setDebuggerProperty"}
 1> [DebugAdapter] <--   R (setDebuggerProperty-5) [18 ms]: {"seq": 7, "type": "response", "request_seq": 5, "success": true, "command": "setDebuggerProperty"}
 1> [DebugAdapter] <--   R (setDebuggerProperty-6) [18 ms]: {"seq": 8, "type": "response", "request_seq": 6, "success": true, "command": "setDebuggerProperty"}
 1> [DebugAdapter] <--   R (setDebuggerProperty-7) [18 ms]: {"seq": 9, "type": "response", "request_seq": 7, "success": true, "command": "setDebuggerProperty"}
 1> [DebugAdapter] <--   R (setDebuggerProperty-8) [18 ms]: {"seq": 10, "type": "response", "request_seq": 8, "success": true, "command": "setDebuggerProperty"}
 1> [DebugAdapter] <--   R (setDebuggerProperty-9) [18 ms]: {"seq": 11, "type": "response", "request_seq": 9, "success": true, "command": "setDebuggerProperty"}
 1> [DebugAdapter] <--   R (setDebuggerProperty-10) [19 ms]: {"seq": 12, "type": "response", "request_seq": 10, "success": true, "command": "setDebuggerProperty"}
 1> [DebugAdapter] <--   R (setDebuggerProperty-11) [21 ms]: {"seq": 13, "type": "response", "request_seq": 11, "success": true, "command": "setDebuggerProperty"}
 1> [DebugAdapter] <--   R (setExceptionBreakpoints-12) [21 ms]: {"seq": 14, "type": "response", "request_seq": 12, "success": true, "command": "setExceptionBreakpoints"}
 1> [DebugAdapter] --> C (configurationDone-13): {"type":"request","command":"configurationDone","arguments":{},"seq":13}
 1> [DebugAdapter] <--   R (configurationDone-13) [5 ms]: {"seq": 15, "type": "response", "request_seq": 13, "success": true, "command": "configurationDone"}
 1> [DebugAdapter] <--   R (launch-2) [681 ms]: {"seq": 16, "type": "response", "request_seq": 2, "success": true, "command": "launch"}
 1> [DebugAdapter] <--   E (process): {"seq": 17, "type": "event", "event": "process", "body": {"pointerSize": 32, "startMethod": "launch", "isLocalProcess": true, "systemProcessId": 1668, "name": "C:\\Users\\vyizh12\\source\\repos\\PythonApplication7\\PythonApplication7\\PythonApplication7.py"}}
 1> [DebugAdapter] <--   E (thread): {"seq": 18, "type": "event", "event": "thread", "body": {"reason": "started", "threadId": 1}}
 1> [DebugAdapter] <--   E (stopped): {"seq": 19, "type": "event", "event": "stopped", "body": {"reason": "entry", "preserveFocusHint": false, "allThreadsStopped": true, "threadId": 1}}
 1> [DebugAdapter] --> C (threads-14): {"type":"request","command":"threads","arguments":{},"seq":14}
 1> [DebugAdapter] <--   R (threads-14) [7 ms]: {"seq": 20, "type": "response", "request_seq": 14, "success": true, "command": "threads", "body": {"threads": [{"id": 1, "name": "MainThread"}]}}
 1> [DebugAdapter] --> C (continue-15): {"type":"request","command":"continue","arguments":{"threadId":1},"seq":15}
 1> [DebugAdapter] <--   E (output): {"seq": 21, "type": "event", "event": "output", "body": {"category": "stdout", "output": "                                        "}}
 1> [DebugAdapter] <--   R (continue-15) [898 ms]: {"seq": 22, "type": "response", "request_seq": 15, "success": true, "command": "continue", "body": {"allThreadsContinued": true}}
 1> [DebugAdapter] <--   E (thread): {"seq": 23, "type": "event", "event": "thread", "body": {"reason": "exited", "threadId": 1}}

VS version

[huguesv]

Additionally, if the "Wait for input when process exits" options are enabled, then debugging session never ends.

[huguesv]

None of those problems appear on 3.7

[int19h]

The "wait for input" thing is a separate issue. The problem there is that the code that does "Press any key to continue ..." checks for sys.stdin being None. Which is the case when you use pythonw.exe in Python 3 - but in Python 2, these are always valid objects, you just get failures if you try to actually use them.

[int19h]

For output, though, is this using "redirectOutput": true in debug configuration, or not? If not, then it's intended behavior - the stuff that goes into Output is the same as what the process would write to its stdout/err. Since pythonw.exe doesn't have stdout/err, there's no output to tee.

[huguesv]

Yes, redirectOutput: true appears in the log.

[int19h]

Sorry, this was wrong. If "redirectOutput" is not set, then nothing is redirected. If it is set, then whatever is written to stdout/err is redirected - but, again, in this case there's no stdout/err.

[int19h]

I'm going to close this one, since the output behavior is by design, and there's a separate issue for wait-on-exit.