Merge pull request #337 from python-greenlet/issue332

Fix assertion error and build

.github/workflows/tests.yml

@@ -26,7 +26,10 @@ jobs:
     strategy:
       matrix:
         python-version: [2.7, 3.5, 3.6, 3.7, 3.8, 3.9, "3.10", "3.11"]
-        os: [ubuntu-latest, macos-latest]
+        # Jan 2023: We have pinned back from ubuntu-latest (which is
+        # now ubuntu 22.04) because older Python versions like
+        # 3.5, 3.6 and presumably 2.7 are not available in it.
+        os: [ubuntu-20.04, macos-latest]
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python
@@ -44,7 +47,6 @@ jobs:
       run: |
         python -m pip install -U pip setuptools wheel
         python -m pip install -U twine
-        python -m pip install -q -U 'faulthandler; python_version == "2.7" and platform_python_implementation == "CPython"'
     - name: Install greenlet
       run: |
         python setup.py bdist_wheel
@@ -67,7 +69,6 @@ jobs:
         path: dist/*whl
     - name: Test
       run: |
-        python -c 'import faulthandler; assert faulthandler.is_enabled()'
         python -c 'import greenlet._greenlet as G; assert G.GREENLET_USE_STANDARD_THREADING'
         python -m unittest discover -v greenlet.tests
     - name: Doctest
@@ -88,7 +89,7 @@ jobs:
     strategy:
       matrix:
         python-version: [2.7, 3.5, "3.11"]
-        os: [ubuntu-latest, macos-latest]
+        os: [ubuntu-20.04, macos-latest]
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python
@@ -106,7 +107,6 @@ jobs:
       run: |
         python -m pip install -U pip setuptools wheel
         python -m pip install -U twine
-        python -m pip install -q -U 'faulthandler; python_version == "2.7" and platform_python_implementation == "CPython"'
     - name: Install greenlet
       env:
         CPPFLAGS: "-DG_USE_STANDARD_THREADING=0 -UNDEBUG -Ofast"
@@ -115,7 +115,6 @@ jobs:
         python -m pip install -U -v -e ".[test,docs]"
     - name: Test
       run: |
-        python -c 'import faulthandler; assert faulthandler.is_enabled()'
         python -c 'import greenlet._greenlet as G; assert not G.GREENLET_USE_STANDARD_THREADING'
         python -m unittest discover -v greenlet.tests
 

CHANGES.rst

@@ -5,7 +5,10 @@
 2.0.2 (unreleased)
 ==================
 
-- Nothing changed yet.
+- Fix calling ``greenlet.settrace()`` with the same tracer object that
+  was currently active. See `issue 332
+  <https://github.com/python-greenlet/greenlet/issues/332>`_.
+
 
 
 2.0.1 (2022-11-07)

appveyor.yml

@@ -200,7 +200,6 @@ build_script:
 
 
 test_script:
-  - "%CMD_IN_ENV% python -c \"import faulthandler; assert faulthandler.is_enabled()\""
   -  if not "%GWHEEL_ONLY%"=="true" %PYEXE% -m zope.testrunner --test-path=src -vvv
 # XXX: Doctest disabled pending sphinx release for 3.10; see tests.yml.
 #  - "%CMD_IN_ENV% python -m sphinx -b doctest -d docs/_build/doctrees docs docs/_build/doctest"

setup.py

@@ -226,7 +226,8 @@ def get_greenlet_version():
         ],
         'test': [
             'objgraph',
-            'faulthandler; python_version == "2.7" and platform_python_implementation == "CPython"',
+            # Sigh, all releases of this were yanked from PyPI.
+            #'faulthandler; python_version == "2.7" and platform_python_implementation == "CPython"',
             'psutil',
         ],
     },

src/greenlet/greenlet_thread_state.hpp

@@ -307,11 +307,7 @@ class ThreadState {
             this->tracefunc.CLEAR();
         }
         else {
-#ifndef NDEBUG
-            Py_ssize_t old_refs = Py_REFCNT(tracefunc);
-#endif
             this->tracefunc = tracefunc;
-            assert(this->tracefunc.REFCNT() == old_refs + 1);
         }
     }
 

src/greenlet/tests/test_tracing.py

@@ -66,6 +66,15 @@ def dummy():
             ('switch', (main, g)),
         ])
 
+    def test_set_same_tracer_twice(self):
+        # https://github.com/python-greenlet/greenlet/issues/332
+        # Our logic in asserting that the tracefunction should
+        # gain a reference was incorrect if the same tracefunction was set
+        # twice.
+        tracer = GreenletTracer()
+        with tracer:
+            greenlet.settrace(tracer)
+
 
 class PythonTracer(object):
     oldtrace = None