pip upgrade warning breaks builds

[den-run-ai]

https://github.com/pythonnet/pythonnet/pull/281#issuecomment-258662260

[IlyaFinkelshteyn]

It looks like pip writes this warning output to stdErr and everything which it written to stdErr is exception for PowerShell. Even though you found a workaround and after we upgrade pip in VHD this can still happen with different supposedly harmless warning. Thus we would recommend run pip as CMD instead of PowerShell.

--ilya.

[IlyaFinkelshteyn]

https://github.com/appveyor/ci/issues/1180

[den-run-ai]

I opened an issue in pip, let's see what they say:

https://github.com/pypa/pip/issues/4117

On Wed, Nov 16, 2016 at 4:42 PM, IlyaFinkelshteyn notifications@github.com wrote:

1180 https://github.com/appveyor/ci/issues/1180

— You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub https://github.com/appveyor/ci/issues/1175#issuecomment-261096367, or mute the thread https://github.com/notifications/unsubscribe-auth/AHgZ5RBbk0QPWTO3XEXllLCbCtNfIuXcks5q-4a8gaJpZM4KzUsp .

[den-run-ai]

@IlyaFinkelshteyn by the way, the warnings should indeed go to stderr, but pip has an option to disable this warning:

https://github.com/pypa/pip/issues/4117#issuecomment-261230489

http://stackoverflow.com/questions/1430956/should-i-output-warnings-to-stderr-or-stdout

[IlyaFinkelshteyn]

Thanks for the info!

[Paebbels]

You can also retranslate all warnings and errors into strings:

program.exe 2>&1 | % { "$_" }