Qt5 fails to build on Windows

[dantti]

Since I got an error when trying to install qt5 with vcpkg on Linux #4645 I decided to try to build
my package on Windows but I got stopped by another error:

-- Installing: C:/src/vcpkg/packages/qt5-base_x86-windows/tools/qt5/uic.exe
CMake Error at scripts/cmake/vcpkg_execute_required_process.cmake:56 (message):
    Command failed: C:/src/vcpkg/downloads/tools/python/python3/python.exe;C:/src/vcpkg/ports/qt5-base/fixcmake.py
    Working Directory: C:/src/vcpkg/packages/qt5-base_x86-windows/share/cmake
    See logs for more information:
      C:\src\vcpkg\buildtrees\qt5-base\fix-cmake-err.log

Call Stack (most recent call first):
  ports/qt5-base/portfile.cmake:141 (vcpkg_execute_required_process)
  scripts/ports.cmake:71 (include)


Error: Building package qt5-base:x86-windows failed with: BUILD_FAILED
Please ensure you're using the latest portfiles with `.\vcpkg update`, then
submit an issue at https://github.com/Microsoft/vcpkg/issues including:
  Package: qt5-base:x86-windows
  Vcpkg version: 2018.10.20-nohash

Additionally, attach any relevant sections from the log files above.

The file fix-cmake-err.log contais:

Fatal Python error: Py_Initialize: unable to load the file system codec
ImportError: No module named 'encodings'

Current thread 0x0000081c (most recent call first):

Thanks

[Neumann-A]

maybe relevant StackOverflow:
https://stackoverflow.com/questions/5694706/py-initialize-fails-unable-to-load-the-file-system-codec
dont now if it is even a vcpkg issue.

[dantti]

well IMO it's a packaging issue:
Command failed: C:/src/vcpkg/downloads/tools/python/python3/python.exe; C:/src/vcpkg/ports/qt5-base/fixcmake.py
If one need to set some ENV variable for this to work the vcpkg pkg needs to set that.

[Neumann-A]

vcpkg adds the internally used python path to the path variable.
The problem here is: To fix the problem more information from your side is required.

Do you have PYTHONPATH or PYTHONHOME defined in your ENV?

[dantti]

Yesterday I did all W10 updates and a new pull which now get's the new Qt 5.11.2, not sure it were the updates or some fix in the packaging for the patch Qt release but it built fine this time without changing any ENV var.
Thanks.
I can now try to build my package 😄