Build Info

• Visual Studio 2015 on Appveyor
• Building for conda-forge
• Builds are here
  • Hanging builds 1, 2
• No errors during building
• Boost 1.65.1

CMake Config

cmake ..\tools\python -LAH -G"NMake Makefiles"              ^
-DCMAKE_BUILD_TYPE="Release"                                ^
-DCMAKE_PREFIX_PATH="%LIBRARY_PREFIX%"                      ^
-DBoost_USE_STATIC_LIBS=0                                   ^
-DBoost_USE_STATIC_RUNTIME=0                                ^
-DBOOST_ROOT="%LIBRARY_PREFIX%"                             ^
-DBOOST_INCLUDEDIR="%LIBRARY_INC%"                          ^
-DBOOST_LIBRARYDIR="%LIBRARY_LIB%"                          ^
-DPYTHON3=%PY3K%                                            ^
-DPYTHON_LIBRARY="%PREFIX%\libs\python%PY_VER_NO_DOT%.lib"  ^
-DPYTHON_INCLUDE_DIR="%PREFIX%\include"                     ^
-DDLIB_LINK_WITH_SQLITE3=0                                  ^
-DDLIB_PNG_SUPPORT=1                                        ^
-DPNG_INCLUDE_DIR="%LIBRARY_INC%"                           ^
-DPNG_PNG_INCLUDE_DIR="%LIBRARY_INC%"                       ^
-DPNG_LIBRARY="%PNG_LIBRARY%"                               ^
-DZLIB_INCLUDE_DIRS="%LIBRARY_INC%"                         ^
-DZLIB_LIBRARIES="%LIBRARY_BIN%\zlib.dll"                   ^
-DDLIB_JPEG_SUPPORT=1                                       ^
-DDLIB_USE_BLAS=0                                           ^
-DDLIB_USE_LAPACK=0                                         ^
-DUSE_SSE2_INSTRUCTIONS=1                                   ^
-DUSE_SSE4_INSTRUCTIONS=0                                   ^
-DUSE_AVX_INSTRUCTIONS=0                                    ^
-DDLIB_USE_CUDA=0                                           ^
-DDLIB_GIF_SUPPORT=0

Reproducing snippet

import sys
import dlib
import numpy as np
from PIL import Image
import bz2

MMOD_URL = 'http://dlib.net/files/mmod_human_face_detector.dat.bz2'
# By участница Udacha (личный архив участницы) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons
IMAGE_URL = 'https://upload.wikimedia.org/wikipedia/commons/6/67/--%D0%98%D0%B7%D0%BE%D0%B1%D1%80%D0%B0%D0%B6%D0%B5%D0%BD%D0%B8%D0%B5-%D0%9F%D0%BE%D1%80%D1%82%D1%80%D0%B5%D1%82%D1%8B-%D0%9C%D0%B8%D1%85%D0%B0%D0%B9%D0%BB%D0%BE%D0%B2%D0%B0_%D0%95%D0%BB%D0%B5%D0%BD%D0%B0_%D0%92%D0%BB%D0%B0%D0%B4%D0%B8%D0%BC%D0%B8%D1%80%D0%BE%D0%B2%D0%BD%D0%B0.jpg'

def download_file(url, out_path):
    import requests

    with requests.get(url, stream=True) as r:
        with open(out_path, 'wb') as f:
            for chunk in r.iter_content(1024):
                f.write(chunk)

def bz2_decompress_inplace(path, out_path):
    with open(path, 'rb') as source:
        with open(out_path, 'wb') as dest:
            dest.write(bz2.decompress(source.read()))

print('Downloading CNN Model')
cnn_model_bz2_local_path = './model.dat.bz2'
cnn_model_dat_local_path = './model.dat'
download_file(MMOD_URL, cnn_model_bz2_local_path)
bz2_decompress_inplace(cnn_model_bz2_local_path, cnn_model_dat_local_path)

print('Downloading Face Image')
image_local_path = './face.png'
download_file(IMAGE_URL, image_local_path)

detector = dlib.cnn_face_detection_model_v1(cnn_model_dat_local_path)
image = np.array(Image.open(image_local_path))
print('Perform detection')
results = detector(image)
print('Detection finished - should immediately exit')
sys.exit(0)

Description

For some reason the Python process hangs indefinitely after a CNN detection is performed on Windows. This doesn’t happen on OSX or Linux and it doesn’t happen if you only build the cnn_face_detection_model_v1 detector - you must execute the detector - which will complete successfully and the Python process continutes as expected. However, when exiting the process in any way (normal termination, exception raised, explicitly calling sys.exit) the process hangs indefinitely.

Looks to me like something funky with the threading keeping the process alive?