python.cfg: Add Py_CLEAR(), and add initial test file (#2110)

.travis.yml

@@ -18,7 +18,7 @@ env:
 before_install:
 # install needed deps
  - travis_retry sudo apt-get update -qq
- - travis_retry sudo apt-get install -qq python-pygments qt5-default qt5-qmake qtbase5-dev qtcreator libxml2-utils libpcre3 gdb unzip wx-common xmlstarlet
+ - travis_retry sudo apt-get install -qq python-pygments qt5-default qt5-qmake qtbase5-dev qtcreator libxml2-utils libpcre3 gdb unzip wx-common xmlstarlet python3-dev
  - travis_retry python2 -m pip install --user pytest==4.6.4
  - travis_retry python2 -m pip install --user pylint
  - travis_retry python2 -m pip install --user unittest2

cfg/python.cfg

@@ -12,7 +12,7 @@
     </arg>
   </function>
   <!-- Those are macros, but it's helpful to declare a function here -->
-  <function name="Py_XINCREF,Py_XDECREF">
+  <function name="Py_XINCREF,Py_XDECREF,Py_CLEAR">
     <leak-ignore/>
     <noreturn>false</noreturn>
     <returnValue type="void"/>

test/cfg/python.c

@@ -0,0 +1,34 @@
+
+// Test library configuration for python.cfg
+//
+// Usage:
+// $ cppcheck --check-library --library=python --enable=information --error-exitcode=1 --inline-suppr --suppress=missingIncludeSystem test/cfg/python.c
+// =>
+// No warnings about bad library configuration, unmatched suppressions, etc. exitcode=0
+//
+
+#define PY_SSIZE_T_CLEAN
+#include <Python.h> // should be the first include
+
+void validCode(PyObject * pPyObjArg)
+{
+    PyObject * pPyObjNULL = NULL;
+    Py_Initialize();
+    Py_INCREF(pPyObjArg);
+    Py_DECREF(pPyObjArg);
+    Py_XINCREF(pPyObjArg);
+    Py_XINCREF(pPyObjNULL);
+    Py_XDECREF(pPyObjArg);
+    Py_XDECREF(pPyObjNULL);
+    Py_CLEAR(pPyObjArg);
+    Py_CLEAR(pPyObjNULL);
+    (void)PyErr_NewException("text", NULL, NULL);
+}
+
+void nullPointer()
+{
+    // cppcheck-suppress nullPointer
+    Py_INCREF(NULL);
+    // cppcheck-suppress nullPointer
+    Py_DECREF(NULL);
+}

test/cfg/runtests.sh

@@ -172,6 +172,33 @@ ${CPPCHECK} ${CPPCHECK_OPT} --inconclusive --library=sqlite3 ${DIR}sqlite3.c
 ${CC} ${CC_OPT} -fopenmp ${DIR}openmp.c
 ${CPPCHECK} ${CPPCHECK_OPT} --library=openmp ${DIR}openmp.c
 
+# python.c
+set +e
+pkg-config --version
+PKGCONFIG_RETURNCODE=$?
+set -e
+if [ $PKGCONFIG_RETURNCODE -ne 0 ]; then
+    echo "pkg-config needed to retrieve Python 3 configuration is not available, skipping syntax check."
+else
+    set +e
+    PYTHON3CONFIG=$(pkg-config --cflags python3)
+    PYTHON3CONFIG_RETURNCODE=$?
+    set -e
+    if [ $PYTHON3CONFIG_RETURNCODE -eq 0 ]; then
+        set +e
+        echo -e "#include <Python.h>" | ${CC} ${CC_OPT} ${PYTHON3CONFIG} -x c -
+        PYTHON3CONFIG_RETURNCODE=$?
+        set -e
+        if [ $PYTHON3CONFIG_RETURNCODE -ne 0 ]; then
+            echo "Python 3 not completely present or not working, skipping syntax check with ${CC}."
+        else
+            echo "Python 3 found and working, checking syntax with ${CC} now."
+            ${CC} ${CC_OPT} ${PYTHON3CONFIG} ${DIR}python.c
+        fi
+    fi
+fi
+${CPPCHECK} ${CPPCHECK_OPT} --library=python ${DIR}python.c
+
 # Check the syntax of the defines in the configuration files
 set +e
 xmlstarlet --version