bpo-43244: Add pycore_ast.h header file (GH-24908)

Move _PyAST_GetDocString() and _PyAST_ExprAsUnicode() functions the
internal C API: from Include/ast.h to a new
Include/internal/pycore_ast.h header file. Don't export these
functions anymore: replace PyAPI_FUNC() with extern.

Remove also unused includes.

Include/ast.h

@@ -9,14 +9,6 @@ extern "C" {
 
 PyAPI_FUNC(int) PyAST_Validate(mod_ty);
 
-/* _PyAST_ExprAsUnicode is defined in ast_unparse.c */
-PyAPI_FUNC(PyObject *) _PyAST_ExprAsUnicode(expr_ty);
-
-/* Return the borrowed reference to the first literal string in the
-   sequence of statements or NULL if it doesn't start from a literal string.
-   Doesn't set exception. */
-PyAPI_FUNC(PyObject *) _PyAST_GetDocString(asdl_stmt_seq *);
-
 #ifdef __cplusplus
 }
 #endif

Include/internal/pycore_ast.h

@@ -0,0 +1,25 @@
+#ifndef Py_INTERNAL_AST_H
+#define Py_INTERNAL_AST_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
+#endif
+
+#include "Python-ast.h"           // expr_ty
+
+/* _PyAST_ExprAsUnicode is defined in ast_unparse.c */
+extern PyObject* _PyAST_ExprAsUnicode(expr_ty);
+
+/* Return the borrowed reference to the first literal string in the
+   sequence of statements or NULL if it doesn't start from a literal string.
+   Doesn't set exception. */
+extern PyObject* _PyAST_GetDocString(asdl_stmt_seq *);
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* !Py_INTERNAL_AST_H */
+

Makefile.pre.in

@@ -1135,6 +1135,7 @@ PYTHON_HEADERS= \
 		\
 		$(srcdir)/Include/internal/pycore_abstract.h \
 		$(srcdir)/Include/internal/pycore_accu.h \
+		$(srcdir)/Include/internal/pycore_ast.h \
 		$(srcdir)/Include/internal/pycore_ast_state.h \
 		$(srcdir)/Include/internal/pycore_atomic.h \
 		$(srcdir)/Include/internal/pycore_atomic_funcs.h \

PCbuild/pythoncore.vcxproj

@@ -175,6 +175,7 @@
     <ClInclude Include="..\Include\import.h" />
     <ClInclude Include="..\Include\internal\pycore_abstract.h" />
     <ClInclude Include="..\Include\internal\pycore_accu.h" />
+    <ClInclude Include="..\Include\internal\pycore_ast.h" />
     <ClInclude Include="..\Include\internal\pycore_ast_state.h" />
     <ClInclude Include="..\Include\internal\pycore_atomic.h" />
     <ClInclude Include="..\Include\internal\pycore_atomic_funcs.h" />

PCbuild/pythoncore.vcxproj.filters

@@ -486,6 +486,9 @@
     <ClInclude Include="..\Include\internal\pycore_accu.h">
       <Filter>Include\internal</Filter>
     </ClInclude>
+    <ClInclude Include="..\Include\internal\pycore_ast.h">
+      <Filter>Include\internal</Filter>
+    </ClInclude>
     <ClInclude Include="..\Include\internal\pycore_ast_state.h">
       <Filter>Include\internal</Filter>
     </ClInclude>

Python/ast_opt.c

@@ -1,7 +1,6 @@
 /* AST Optimizer */
 #include "Python.h"
-#include "Python-ast.h"
-#include "ast.h"
+#include "pycore_ast.h"           // _PyAST_GetDocString()
 
 
 static int

Python/compile.c

@@ -22,16 +22,15 @@
  */
 
 #include "Python.h"
+#include "pycore_ast.h"           // _PyAST_GetDocString()
 #include "pycore_pymem.h"         // _PyMem_IsPtrFreed()
 #include "pycore_long.h"          // _PyLong_GetZero()
 
-#include "Python-ast.h"
-#include "ast.h"
-#include "code.h"
-#include "symtable.h"
+#include "symtable.h"             // struct symtable
 #define NEED_OPCODE_JUMP_TABLES
-#include "opcode.h"
-#include "wordcode_helpers.h"
+#include "opcode.h"               // EXTENDED_ARG
+#include "wordcode_helpers.h"     // instrsize()
+
 
 #define DEFAULT_BLOCK_SIZE 16
 #define DEFAULT_BLOCKS 8

Python/future.c

@@ -1,9 +1,5 @@
 #include "Python.h"
-#include "Python-ast.h"
-#include "token.h"
-#include "code.h"
-#include "symtable.h"
-#include "ast.h"
+#include "pycore_ast.h"           // _PyAST_GetDocString()
 
 #define UNDEFINED_FUTURE_FEATURE "future feature %.100s is not defined"
 #define ERR_LATE_FUTURE \