Live text handler: Handle is invalid error raised when console windows appear and disappear quickly

[josephsl]

Hi,

I'm seeing this error more frequently these days (perhaps due to use of some apps that pops open cmd.exe or powerShell for a quick task). Although there is no definitive reproduction steps, the end result is as follows:

1. Perform a task (say, doing a say all).
2. A console window pops up and closes immediately.
3. An error tone is heard with the following traceback:

ERROR - NVDAObjects.behaviors.LiveText._monitor (11:13:42.960):
Error getting initial lines
Traceback (most recent call last):
File "NVDAObjects\behaviors.pyc", line 260, in _monitor
File "NVDAObjects\window\winConsole.pyc", line 49, in _getTextLines
File "winConsoleHandler.pyc", line 121, in getConsoleVisibleLines
File "wincon.pyc", line 70, in GetConsoleScreenBufferInfo
WindowsError: [Error 6] The handle is invalid.

Specs:

• NvDA version: next.14089
• OS: Windows 10 Version 1703 (15063)

Thanks.

[Brian1Gaff]

Yes getting this when i use a small batch file to update a registry entry on some software to make it self voice as the box is not usable in nvda to set it on. Sometimes this results in the window for the command getting left on top as well, but not often. Brian bglists@blueyonder.co.uk

[jcsteh]

This occurs because the console disappears before NVDA can get anything from it. Most users aren't affected by this error, since it doesn't cause any broken behaviour and we dont do error sounds in stable releases. The only thing we can do here is catch this and ignore it. I still think we should log it as a debugWarning, since it might be important in some cases.

The appropriate place to catch this is probably NVDAObjects.window.winConsole.WinConsole._getTextLines. It should probably check the error code (e.winerror), not just ignore all WindowsError exceptions.

[Adriani90]

cc: @derekriemer, @LeonarddeR