bpo-41078: Add pycore_list.h internal header file (GH-21057)

* Move _PyList_ITEMS() to pycore_list.h.
* The C extension "_heapq" is now built with Py_BUILD_CORE_MODULE
  macro defined to access the internal C API.

8 files changed, 31 insertions, 4 deletions

diff --git a/Include/cpython/listobject.h b/Include/cpython/listobject.h
index b1af5f67644..70b9d83d8a2 100644
--- a/Include/cpython/listobject.h
+++ b/Include/cpython/listobject.h
@@ -32,4 +32,3 @@ PyAPI_FUNC(void) _PyList_DebugMallocStats(FILE *out);
 #define PyList_GET_ITEM(op, i) (_PyList_CAST(op)->ob_item[i])
 #define PyList_SET_ITEM(op, i, v) (_PyList_CAST(op)->ob_item[i] = (v))
 #define PyList_GET_SIZE(op)    Py_SIZE(_PyList_CAST(op))
-#define _PyList_ITEMS(op)      (_PyList_CAST(op)->ob_item)
diff --git a/Include/internal/pycore_list.h b/Include/internal/pycore_list.h
new file mode 100644
index 00000000000..f18fb052c49
--- /dev/null
+++ b/Include/internal/pycore_list.h
@@ -0,0 +1,20 @@
+#ifndef Py_INTERNAL_LIST_H
+#define Py_INTERNAL_LIST_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
+#endif
+
+#include "listobject.h"           // _PyList_CAST()
+
+
+#define _PyList_ITEMS(op) (_PyList_CAST(op)->ob_item)
+
+
+#ifdef __cplusplus
+}
+#endif
+#endif   /* !Py_INTERNAL_LIST_H */
diff --git a/Makefile.pre.in b/Makefile.pre.in
index a52a97f7969..3428b9842a5 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -1110,6 +1110,7 @@ PYTHON_HEADERS= \
 		$(srcdir)/Include/internal/pycore_import.h \
 		$(srcdir)/Include/internal/pycore_initconfig.h \
 		$(srcdir)/Include/internal/pycore_interp.h \
+		$(srcdir)/Include/internal/pycore_list.h \
 		$(srcdir)/Include/internal/pycore_object.h \
 		$(srcdir)/Include/internal/pycore_pathconfig.h \
 		$(srcdir)/Include/internal/pycore_pyerrors.h \
diff --git a/Modules/Setup b/Modules/Setup
index 5d428d5b8ba..470bf6bc2ef 100644
--- a/Modules/Setup
+++ b/Modules/Setup
@@ -180,7 +180,7 @@ _symtable symtablemodule.c
 #_datetime _datetimemodule.c	# datetime accelerator
 #_zoneinfo _zoneinfo.c	# zoneinfo accelerator
 #_bisect _bisectmodule.c	# Bisection algorithms
-#_heapq _heapqmodule.c	# Heap queue algorithm
+#_heapq _heapqmodule.c -DPy_BUILD_CORE_MODULE	# Heap queue algorithm
 #_asyncio _asynciomodule.c  # Fast asyncio Future
 #_json -I$(srcdir)/Include/internal -DPy_BUILD_CORE_BUILTIN _json.c	# _json speedups
 #_statistics _statisticsmodule.c # statistics accelerator
diff --git a/Modules/_heapqmodule.c b/Modules/_heapqmodule.c
index 193478d79b4..20468c28f24 100644
--- a/Modules/_heapqmodule.c
+++ b/Modules/_heapqmodule.c
@@ -7,9 +7,11 @@ annotated by François Pinard, and converted to C by Raymond Hettinger.
 */
 
 #include "Python.h"
+#include "pycore_list.h"          // _PyList_ITEMS()
 
 #include "clinic/_heapqmodule.c.h"
 
+
 /*[clinic input]
 module _heapq
 [clinic start generated code]*/
diff --git a/PCbuild/pythoncore.vcxproj b/PCbuild/pythoncore.vcxproj
index 00714757f64..54e23c2c2b5 100644
--- a/PCbuild/pythoncore.vcxproj
+++ b/PCbuild/pythoncore.vcxproj
@@ -165,8 +165,8 @@
     <ClInclude Include="..\Include\internal\pycore_abstract.h" />
     <ClInclude Include="..\Include\internal\pycore_accu.h" />
     <ClInclude Include="..\Include\internal\pycore_atomic.h" />
-    <ClInclude Include="..\Include\internal\pycore_bytes_methods.h" />
     <ClInclude Include="..\Include\internal\pycore_bitutils.h" />
+    <ClInclude Include="..\Include\internal\pycore_bytes_methods.h" />
     <ClInclude Include="..\Include\internal\pycore_call.h" />
     <ClInclude Include="..\Include\internal\pycore_ceval.h" />
     <ClInclude Include="..\Include\internal\pycore_code.h" />
@@ -181,6 +181,7 @@
     <ClInclude Include="..\Include\internal\pycore_import.h" />
     <ClInclude Include="..\Include\internal\pycore_initconfig.h" />
     <ClInclude Include="..\Include\internal\pycore_interp.h" />
+    <ClInclude Include="..\Include\internal\pycore_list.h" />
     <ClInclude Include="..\Include\internal\pycore_object.h" />
     <ClInclude Include="..\Include\internal\pycore_pathconfig.h" />
     <ClInclude Include="..\Include\internal\pycore_pyerrors.h" />
diff --git a/PCbuild/pythoncore.vcxproj.filters b/PCbuild/pythoncore.vcxproj.filters
index ddcdaf47190..4ba0bc2ac3b 100644
--- a/PCbuild/pythoncore.vcxproj.filters
+++ b/PCbuild/pythoncore.vcxproj.filters
@@ -240,6 +240,9 @@
     <ClInclude Include="..\Include\internal\pycore_interp.h">
       <Filter>Include</Filter>
     </ClInclude>
+    <ClInclude Include="..\Include\internal\pycore_list.h">
+      <Filter>Include</Filter>
+    </ClInclude>
     <ClInclude Include="..\Include\internal\pycore_object.h">
       <Filter>Include</Filter>
     </ClInclude>
diff --git a/setup.py b/setup.py
index 648e4e6a893..21a5a58981f 100644
--- a/setup.py
+++ b/setup.py
@@ -863,7 +863,8 @@ class PyBuildExt(build_ext):
         # bisect
         self.add(Extension("_bisect", ["_bisectmodule.c"]))
         # heapq
-        self.add(Extension("_heapq", ["_heapqmodule.c"]))
+        self.add(Extension("_heapq", ["_heapqmodule.c"],
+                           extra_compile_args=['-DPy_BUILD_CORE_MODULE']))
         # C-optimized pickle replacement
         self.add(Extension("_pickle", ["_pickle.c"],
                            extra_compile_args=['-DPy_BUILD_CORE_MODULE']))