https://github.com/python/cpython/commit/d91cc9db155024b0a221cf32f4f49617544618bf
commit: d91cc9db155024b0a221cf32f4f49617544618bf
branch: main
author: Petr Viktorin <[email protected]>
committer: encukou <[email protected]>
date: 2025-03-04T14:10:09+01:00
summary:
gh-129666: Add C11/C++11 to docs and -pedantic-errors to GCC/clang
test_c[pp]ext tests (GH-130692)
Disable pedantic check for c++03 (unlimited API)
Also add a check for c++03 *limited* API, which passes in pedantic mode
after removing a comma in the `PySendResult` declaration, and allowing
`long long`.
files:
M Doc/c-api/intro.rst
M Include/object.h
M Lib/test/test_cext/__init__.py
M Lib/test/test_cext/extension.c
M Lib/test/test_cext/setup.py
M Lib/test/test_cppext/__init__.py
M Lib/test/test_cppext/extension.cpp
M Lib/test/test_cppext/setup.py
diff --git a/Doc/c-api/intro.rst b/Doc/c-api/intro.rst
index 8ef463e3f88ca8..76d7d5793428f8 100644
--- a/Doc/c-api/intro.rst
+++ b/Doc/c-api/intro.rst
@@ -30,6 +30,16 @@ familiar with writing an extension before attempting to
embed Python in a real
application.
+Language version compatibility
+==============================
+
+Python's C API is compatible with C11 and C++11 versions of C and C++.
+
+This is a lower limit: the C API does not require features from later
+C/C++ versions.
+You do *not* need to enable your compiler's "c11 mode".
+
+
Coding standards
================
diff --git a/Include/object.h b/Include/object.h
index da7b3668c033f4..7d1667d889cb43 100644
--- a/Include/object.h
+++ b/Include/object.h
@@ -683,7 +683,7 @@ PyAPI_DATA(PyObject) _Py_NotImplementedStruct; /* Don't use
this directly */
typedef enum {
PYGEN_RETURN = 0,
PYGEN_ERROR = -1,
- PYGEN_NEXT = 1,
+ PYGEN_NEXT = 1
} PySendResult;
#endif
diff --git a/Lib/test/test_cext/__init__.py b/Lib/test/test_cext/__init__.py
index 54859f9ff7622d..402a2d04fa875e 100644
--- a/Lib/test/test_cext/__init__.py
+++ b/Lib/test/test_cext/__init__.py
@@ -38,6 +38,9 @@ def test_build_c11(self):
@unittest.skipIf(support.MS_WINDOWS, "MSVC doesn't support /std:c99")
def test_build_c99(self):
+ # In public docs, we say C API is compatible with C11. However,
+ # in practice we do maintain C99 compatibility in public headers.
+ # Please ask the C API WG before adding a new C11-only feature.
self.check_build('_test_c99_cext', std='c99')
@support.requires_gil_enabled('incompatible with Free Threading')
diff --git a/Lib/test/test_cext/extension.c b/Lib/test/test_cext/extension.c
index b76abe1d74c628..64629c5a6da8cd 100644
--- a/Lib/test/test_cext/extension.c
+++ b/Lib/test/test_cext/extension.c
@@ -58,11 +58,24 @@ _testcext_exec(
return 0;
}
+// Converting from function pointer to void* has undefined behavior, but
+// works on all known platforms, and CPython's module and type slots currently
+// need it.
+// (GCC doesn't have a narrower category for this than -Wpedantic.)
+_Py_COMP_DIAG_PUSH
+#if defined(__GNUC__)
+#pragma GCC diagnostic ignored "-Wpedantic"
+#elif defined(__clang__)
+#pragma clang diagnostic ignored "-Wpedantic"
+#endif
+
static PyModuleDef_Slot _testcext_slots[] = {
{Py_mod_exec, (void*)_testcext_exec},
{0, NULL}
};
+_Py_COMP_DIAG_POP
+
PyDoc_STRVAR(_testcext_doc, "C test extension.");
diff --git a/Lib/test/test_cext/setup.py b/Lib/test/test_cext/setup.py
index e97749b45ea6f3..1275282983f7ff 100644
--- a/Lib/test/test_cext/setup.py
+++ b/Lib/test/test_cext/setup.py
@@ -21,6 +21,9 @@
# gh-120593: Check the 'const' qualifier
'-Wcast-qual',
+
+ # Ask for strict(er) compliance with the standard
+ '-pedantic-errors',
]
if not support.Py_GIL_DISABLED:
CFLAGS.append(
diff --git a/Lib/test/test_cppext/__init__.py b/Lib/test/test_cppext/__init__.py
index d5195227308fec..13f9ea1c56cca5 100644
--- a/Lib/test/test_cppext/__init__.py
+++ b/Lib/test/test_cppext/__init__.py
@@ -29,8 +29,15 @@ def test_build(self):
self.check_build('_testcppext')
def test_build_cpp03(self):
+ # In public docs, we say C API is compatible with C++11. However,
+ # in practice we do maintain C++03 compatibility in public headers.
+ # Please ask the C API WG before adding a new C++11-only feature.
self.check_build('_testcpp03ext', std='c++03')
+ @support.requires_gil_enabled('incompatible with Free Threading')
+ def test_build_limited_cpp03(self):
+ self.check_build('_test_limited_cpp03ext', std='c++03', limited=True)
+
@unittest.skipIf(support.MS_WINDOWS, "MSVC doesn't support /std:c++11")
def test_build_cpp11(self):
self.check_build('_testcpp11ext', std='c++11')
diff --git a/Lib/test/test_cppext/extension.cpp
b/Lib/test/test_cppext/extension.cpp
index 500d5918145c00..5b3571b295bec3 100644
--- a/Lib/test/test_cppext/extension.cpp
+++ b/Lib/test/test_cppext/extension.cpp
@@ -161,11 +161,24 @@ class VirtualPyObject : public PyObject {
int VirtualPyObject::instance_count = 0;
+// Converting from function pointer to void* has undefined behavior, but
+// works on all known platforms, and CPython's module and type slots currently
+// need it.
+// (GCC doesn't have a narrower category for this than -Wpedantic.)
+_Py_COMP_DIAG_PUSH
+#if defined(__GNUC__)
+#pragma GCC diagnostic ignored "-Wpedantic"
+#elif defined(__clang__)
+#pragma clang diagnostic ignored "-Wpedantic"
+#endif
+
PyType_Slot VirtualPyObject_Slots[] = {
{Py_tp_free, (void*)VirtualPyObject::dealloc},
{0, _Py_NULL},
};
+_Py_COMP_DIAG_POP
+
PyType_Spec VirtualPyObject_Spec = {
/* .name */ STR(MODULE_NAME) ".VirtualPyObject",
/* .basicsize */ sizeof(VirtualPyObject),
@@ -241,11 +254,20 @@ _testcppext_exec(PyObject *module)
return 0;
}
+// Need to ignore "-Wpedantic" warnings; see VirtualPyObject_Slots above
+_Py_COMP_DIAG_PUSH
+#if defined(__GNUC__)
+#pragma GCC diagnostic ignored "-Wpedantic"
+#elif defined(__clang__)
+#pragma clang diagnostic ignored "-Wpedantic"
+#endif
+
static PyModuleDef_Slot _testcppext_slots[] = {
{Py_mod_exec, reinterpret_cast<void*>(_testcppext_exec)},
{0, _Py_NULL}
};
+_Py_COMP_DIAG_POP
PyDoc_STRVAR(_testcppext_doc, "C++ test extension.");
diff --git a/Lib/test/test_cppext/setup.py b/Lib/test/test_cppext/setup.py
index 019ff18446a2eb..b30c9e2746c980 100644
--- a/Lib/test/test_cppext/setup.py
+++ b/Lib/test/test_cppext/setup.py
@@ -19,6 +19,17 @@
# warnings
'-Werror',
]
+
+ CPPFLAGS_PEDANTIC = [
+ # Ask for strict(er) compliance with the standard.
+ # We cannot do this for c++03 unlimited API, since several headers in
+ # Include/cpython/ use commas at end of `enum` declarations, a C++11
+ # feature for which GCC has no narrower option than -Wpedantic itself.
+ '-pedantic-errors',
+
+ # We also use `long long`, a C++11 feature we can enable individually.
+ '-Wno-long-long',
+ ]
else:
# MSVC compiler flags
CPPFLAGS = [
@@ -27,6 +38,7 @@
# Treat all compiler warnings as compiler errors
'/WX',
]
+ CPPFLAGS_PEDANTIC = []
def main():
@@ -45,6 +57,10 @@ def main():
else:
cppflags.append(f'-std={std}')
+ if limited or (std != 'c++03'):
+ # See CPPFLAGS_PEDANTIC docstring
+ cppflags.extend(CPPFLAGS_PEDANTIC)
+
# gh-105776: When "gcc -std=11" is used as the C++ compiler, -std=c11
# option emits a C++ compiler warning. Remove "-std11" option from the
# CC command.
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