MAINT: init file and mpl updates (#70)

* MAINT: init file and mpl updates

* we've been getting reports of new Python 3.7
patch releases from Windows store causing SciPy DLL
load issues: scipy/scipy#11826

* so, extend the `_distributor_init.py` machinery usage
to include Python 3.7 and up for our wheels

* simplify the appveyor `matplotlib` install now that
there are stable releases available for Python `3.8`

* MAINT: update .travis.yml

* fix warnings in `.travis.yml` based on feedback from
https://config.travis-ci.com/explore

* bump distro to `bionic` since NumPy did this recently too

* attempting to restore Travis CI runs to our wheels
build matrix

* MAINT: revise PR 70

* try using `[System.Version]` for more robust
Python version comparisons in powershell

* MAINT: PR 70 revisions

* update minimum NumPy version to `1.14.5`

* the distutils override for appveyor/Windows
builds now only happens for Python < 3.7, since
we have now added the `_distributor_init.py`
for Python 3.7 (not just Python 3.8)

* DEBUG: try newer NumPy

* try using newer NumPy version for Windows Python 3.7
builds, to see if this helps `check_installed_package.py`

* Add debug prints to _distributor_init.py

* Debug print contents of .libs path for DLLs

* Make sure libs_path exists before trying to debug print contents.

* DEBUG: simplify CI matrix for iteration.

* DEBUG: more debug prints near point of 32-bit Python 3.7 DLL resolution failure.

* DEBUG: try moving into DLL dir

* try to solve DLL resolution issues for older
(32-bit) Python versions by temporarily moving into the
path where they are stored prior to load attempts
in `_distributor_init.py`

* Revert "DEBUG: simplify CI matrix for iteration."

This reverts commit 46e69e1.

* MAINT: PR 70 cleanup

* remove some debug prints

* revert some debug changes

* use `_distributor_init.py` with Python 3.6+
(all supported Python versions)

* MAINT: PR 70 revisions

* wrap the `_distributor_init.py` `os.chdir` code in a
`try .. finally` block to ensure restoration of the working
directory if something fails

* substantially expand the comments describing the rationale
for the working directory changes in `_distributor_init.py`

* MAINT: PR 70 revisions

* sync multibuild submodule to latest `devel` branch
checkout in attempt to deal with Travis CI failures
that just started appearing

.travis.yml

@@ -4,10 +4,10 @@ env:
         # Also see DAILY_COMMIT below
         - BUILD_COMMIT=master
         - PLAT=x86_64
-        - NP_BUILD_DEP="numpy==1.13.3"
+        - NP_BUILD_DEP="numpy==1.14.5"
         - CYTHON_BUILD_DEP="Cython==0.29.14"
         - PYBIND11_BUILD_DEP="pybind11==2.4.3"
-        - NP_TEST_DEP="numpy==1.13.3"
+        - NP_TEST_DEP="numpy==1.14.5"
         - UNICODE_WIDTH=32
         - MANYLINUX_URL="https://5cf40426d9f06eb7461d-6fe47d9331aba7cd62fc36c7196769e4.ssl.cf2.rackcdn.com"
         - WHEELHOUSE_UPLOADER_USERNAME=travis-worker
@@ -19,28 +19,26 @@ env:
         - DAILY_COMMIT=master
 
 language: python
-# Default Python version is usually 2.7
-python: 3.5
-sudo: required
-dist: trusty
+dist: bionic
 services: docker
+os: linux
 
-matrix:
+jobs:
   exclude:
       # Exclude the default Python 3.5 build
       - python: 3.5
   include:
     - os: linux
       env:
         - MB_PYTHON_VERSION=3.6
-        - NP_BUILD_DEP=numpy==1.13.3
-        - NP_TEST_DEP=numpy==1.13.3
+        - NP_BUILD_DEP=numpy==1.14.5
+        - NP_TEST_DEP=numpy==1.14.5
     - os: linux
       env:
         - MB_PYTHON_VERSION=3.6
         - PLAT=i686
-        - NP_BUILD_DEP=numpy==1.13.3
-        - NP_TEST_DEP=numpy==1.13.3
+        - NP_BUILD_DEP=numpy==1.14.5
+        - NP_TEST_DEP=numpy==1.14.5
     - os: linux
       env:
         - MB_PYTHON_VERSION=3.7
@@ -71,8 +69,8 @@ matrix:
       language: generic
       env:
         - MB_PYTHON_VERSION=3.6
-        - NP_BUILD_DEP=numpy==1.13.3
-        - NP_TEST_DEP=numpy==1.13.3
+        - NP_BUILD_DEP=numpy==1.14.5
+        - NP_TEST_DEP=numpy==1.14.5
     - os: osx
       language: generic
       env:

_distributor_init.py

@@ -22,5 +22,42 @@
     libs_path = os.path.abspath(os.path.join(os.path.dirname(__file__),
                                              '.libs'))
     if os.path.isdir(libs_path):
-        for filename in glob.glob(os.path.join(libs_path, '*dll')):
-            WinDLL(os.path.abspath(filename))
+        # for Python >= 3.8, DLL resolution ignores the PATH variable
+        # and the current working directory; see release notes:
+        # https://docs.python.org/3/whatsnew/3.8.html#bpo-36085-whatsnew
+        # Only the system paths, the directory containing the DLL, and 
+        # directories added with add_dll_directory() are searched for 
+        # load-time dependencies with Python >= 3.8
+
+        # this module was originally added to support DLL resolution in
+        # Python 3.8 because of the changes described above--providing the
+        # absolute paths to the DLLs allowed for proper resolution/loading
+
+        # however, we also started to receive reports of problems with DLL
+        # resolution with Python 3.7 that were sometimes alleviated with
+        # inclusion of the _distributor_init.py module; see SciPy main 
+        # repo gh-11826
+
+        # we noticed in scipy-wheels repo gh-70 that inclusion of
+        # _distributor_init.py in 32-bit wheels for Python 3.7 resulted
+        # in failures in DLL resolution (64-bit 3.7 did not)
+        # as a result, we decided to combine both the old (working directory)
+        # and new (absolute path to DLL location) DLL resolution mechanisms
+        # to improve the chances of resolving DLLs across a wider range of
+        # Python versions
+
+        # we did not experiment with manipulating the PATH environment variable
+        # to include libs_path; it is not immediately clear if this would have
+        # robustness or security advantages over changing working directories
+        # as done below
+
+        # we should remove the working directory shims when our minimum supported
+        # Python version is 3.8 and trust the improvements to secure DLL loading
+        # in the standard lib for Python >= 3.8
+        try:
+            owd = os.getcwd()
+            os.chdir(libs_path)
+            for filename in glob.glob(os.path.join(libs_path, '*dll')):
+                WinDLL(os.path.abspath(filename))
+        finally:
+            os.chdir(owd)

appveyor.yml

@@ -17,7 +17,7 @@ environment:
       OPENBLAS_32_SHA256: 06e3d38f01119afe5d6630d7ad310a873f8bede52fe71f2d0e2ebf3476194892
       OPENBLAS_64_SHA256: 4d496081543c61bfb8069c1a12dfc2c0371cf9c59f9a4488e2e416dd4026357e
       CYTHON_BUILD_DEP: Cython==0.29.14
-      NUMPY_TEST_DEP: numpy==1.13.3
+      NUMPY_TEST_DEP: numpy==1.14.5
       PYBIND11_BUILD_DEP: pybind11==2.4.3
       TEST_MODE: fast
       APPVEYOR_SAVE_CACHE_ON_ERROR: true
@@ -61,12 +61,12 @@ environment:
     - PYTHON: C:\Python36
       PYTHON_VERSION: 3.6
       PYTHON_ARCH: 32
-      NUMPY_BUILD_DEP: numpy==1.13.3
+      NUMPY_BUILD_DEP: numpy==1.14.5
 
     - PYTHON: C:\Python36-x64
       PYTHON_VERSION: 3.6
       PYTHON_ARCH: 64
-      NUMPY_BUILD_DEP: numpy==1.13.3
+      NUMPY_BUILD_DEP: numpy==1.14.5
 
 init:
   - "ECHO %PYTHON% %PYTHON_VERSION% %PYTHON_ARCH%"
@@ -154,7 +154,7 @@ install:
   # Replace numpy distutils with a version that can build with msvc + mingw-gfortran.
   - ps: |
       $PYTHON_VERSION = $env:PYTHON_VERSION
-      If ($PYTHON_VERSION -ne 3.8) {
+      If ([System.Version]"$PYTHON_VERSION" -lt [System.Version]"3.8") {
       $NumpyDir = $((python -c 'import os; import numpy; print(os.path.dirname(numpy.__file__))') | Out-String).Trim()
       rm -r -Force "$NumpyDir\distutils"
       mv numpy-distutils\numpy\distutils $NumpyDir
@@ -166,17 +166,14 @@ build_script:
   - cd scipy
   - git checkout %BUILD_COMMIT%
   # we use a distribution file to assist in loading
-  # DLLs with recent Python versions (>= 3.8)
+  # DLLs
   - ps: |
-      $PYTHON_VERSION = $env:PYTHON_VERSION
-      If ($PYTHON_VERSION -eq 3.8) {
-          cd ..
-          $cwd = Get-Location
-          ls $cwd
-          rm -Force $cwd/scipy/scipy/_distributor_init.py
-          mv $cwd/_distributor_init.py $cwd/scipy/scipy/
-          cd scipy
-      }
+      cd ..
+      $cwd = Get-Location
+      ls $cwd
+      rm -Force $cwd/scipy/scipy/_distributor_init.py
+      mv $cwd/_distributor_init.py $cwd/scipy/scipy/
+      cd scipy
   # Append license text relevant for the built wheel
   - type ..\LICENSE_win32.txt >> LICENSE.txt
   # Copy over additional DLLs to bundle to the wheels.
@@ -209,14 +206,7 @@ build_script:
 
 before_test:
   # Install test requirements.
-  - python -m pip install pytest pytest-xdist pytest-faulthandler pytest-env Pillow mpmath
-  - ps: |
-      $PYTHON_VERSION = $env:PYTHON_VERSION
-      If ($PYTHON_VERSION -eq 3.8) {
-          python -m pip install matplotlib==3.2.0rc1
-      } Else {
-          python -m pip install matplotlib
-      }
+  - python -m pip install pytest pytest-xdist pytest-faulthandler pytest-env Pillow mpmath matplotlib
 
   # Upgrade numpy to the version used for testing
   - python -m pip install "%NUMPY_TEST_DEP%"