Merge pull request matplotlib#13937 from anntzer/faultless

Use PYTHONFAULTHANDLER to switch on the Python fault handler.

Author: dopplershift

.appveyor.yml

@@ -14,6 +14,7 @@ clone_depth: 50
 environment:
 
   global:
+    PYTHONFAULTHANDLER: 1
     PYTHONIOENCODING: UTF-8
     PYTEST_ARGS: -raR --numprocesses=auto --timeout=300 --durations=25
                  --cov-report= --cov=lib --log-level=DEBUG

azure-pipelines.yml

@@ -23,25 +23,21 @@ jobs:
       architecture: 'x64'
 
   - script: |
-
       python -m pip install --upgrade pip
       pip install -r requirements/testing/travis_all.txt -r requirements/testing/travis36.txt
-
     displayName: 'Install dependencies'
 
   - script: |
-
       export MPLLOCALFREETYPE=1
       pip install -ve .
-
     displayName: "Install self"
 
   - script: env
     displayName: 'print env'
 
   - script: |
       env
-      pytest --junitxml=junit/test-results.xml -raR --maxfail=50 --timeout=300 --durations=25 --cov-report= --cov=lib -n 2 --log-level=DEBUG
+      PYTHONFAULTHANDLER=1 pytest --junitxml=junit/test-results.xml -raR --maxfail=50 --timeout=300 --durations=25 --cov-report= --cov=lib -n 2 --log-level=DEBUG
     displayName: 'pytest'
 
   - task: PublishTestResults@2

doc/api/next_api_changes/2019-04-13-AL.rst

@@ -0,0 +1,4 @@
+The test suite no longer turns on the Python fault handler by default
+`````````````````````````````````````````````````````````````````````
+
+Set the standard ``PYTHONFAULTHANDLER`` environment variable to do so.

lib/matplotlib/__init__.py

@@ -1308,16 +1308,6 @@ def tk_window_focus():
 
 
 def _init_tests():
-    # CPython's faulthandler since v3.6 handles exceptions on Windows
-    # https://bugs.python.org/issue23848 but until v3.6.4 it was printing
-    # non-fatal exceptions https://bugs.python.org/issue30557
-    import platform
-    if not (sys.platform == 'win32' and
-            (3, 6) < sys.version_info < (3, 6, 4) and
-            platform.python_implementation() == 'CPython'):
-        import faulthandler
-        faulthandler.enable()
-
     # The version of FreeType to install locally for running the
     # tests.  This must match the value in `setupext.py`
     LOCAL_FREETYPE_VERSION = '2.6.1'

requirements/testing/travis_all.txt

@@ -7,7 +7,6 @@ pillow
 pyparsing
 pytest!=4.6.0
 pytest-cov
-pytest-faulthandler
 pytest-rerunfailures
 pytest-timeout
 pytest-xdist