Add Lazy Imports to 3.14

Summary:
Add Lazy Imports to Python 3.14. This Diff is the result of squashing this stack - D82821767.

__**File Regeneration**__
`./configure && make clean && make regen-all`
`./third-party/python/3.14/build/gen-checked-in-artifacts.sh`
`./third-party/python/3.14/build/gen-cinderx.sh`

__**Patch Details**__

This diff adds a patch to the `3.14` Meta-internal fork.

Lazy Imports 3.14

Reviewed By: itamaro

Differential Revision: D83595369

fbshipit-source-id: 02361bc1b2503c8afdef6081956163bca3a65311

Author: Subbarao Garlapati

Include/Python.h

@@ -96,6 +96,7 @@
 #include "rangeobject.h"
 #include "memoryobject.h"
 #include "tupleobject.h"
+#include "lazyimportobject.h"
 #include "listobject.h"
 #include "dictobject.h"
 #include "cpython/odictobject.h"

Include/cpython/compile.h

@@ -20,9 +20,16 @@
 #define PyCF_ALLOW_TOP_LEVEL_AWAIT 0x2000
 #define PyCF_ALLOW_INCOMPLETE_INPUT 0x4000
 #define PyCF_OPTIMIZED_AST (0x8000 | PyCF_ONLY_AST)
+#ifdef ENABLE_LAZY_IMPORTS
+#define PyCF_DISABLE_LAZY_IMPORTS 0x10000
+#define PyCF_COMPILE_MASK (PyCF_ONLY_AST | PyCF_ALLOW_TOP_LEVEL_AWAIT | \
+                           PyCF_TYPE_COMMENTS | PyCF_DONT_IMPLY_DEDENT | \
+                           PyCF_ALLOW_INCOMPLETE_INPUT | PyCF_OPTIMIZED_AST | PyCF_DISABLE_LAZY_IMPORTS)
+#else
 #define PyCF_COMPILE_MASK (PyCF_ONLY_AST | PyCF_ALLOW_TOP_LEVEL_AWAIT | \
                            PyCF_TYPE_COMMENTS | PyCF_DONT_IMPLY_DEDENT | \
                            PyCF_ALLOW_INCOMPLETE_INPUT | PyCF_OPTIMIZED_AST)
+#endif
 
 typedef struct {
     int cf_flags;  /* bitmask of CO_xxx flags relevant to future */

Include/cpython/dictobject.h

@@ -75,6 +75,16 @@ Py_DEPRECATED(3.14) PyAPI_FUNC(PyObject *) _PyDict_Pop(
     PyObject *key,
     PyObject *default_value);
 
+#ifdef ENABLE_LAZY_IMPORTS
+PyAPI_FUNC(int) _PyDict_NextKeepLazy(
+    PyObject *mp, Py_ssize_t *pos, PyObject **key, PyObject **value);
+PyAPI_FUNC(int) PyDict_NextWithError(
+    PyObject *mp, Py_ssize_t *pos, PyObject **key, PyObject **value);
+PyAPI_FUNC(Py_ssize_t) PyDict_ResolveLazyImports(PyObject *);
+PyAPI_FUNC(int) PyDict_IsLazyImport(PyObject *mp, PyObject *name);
+PyAPI_FUNC(int) _PyDict_GetItemRefKeepLazy(PyObject *mp, PyObject *key, PyObject **result);
+#endif
+
 /* Dictionary watchers */
 
 #define PY_FOREACH_DICT_EVENT(V) \

Include/cpython/import.h

@@ -2,6 +2,16 @@
 #  error "this header file must not be included directly"
 #endif
 
+#ifdef ENABLE_LAZY_IMPORTS
+PyAPI_FUNC(PyObject *) _PyImport_GetModule(PyThreadState *tstate, PyObject *name);
+PyAPI_FUNC(PyObject *) PyImport_SetLazyImports(
+    PyObject *enabled, PyObject *excluding, PyObject *eager);
+PyAPI_FUNC(PyObject *) _PyImport_SetLazyImportsInModule(
+    PyObject *enabled);
+PyAPI_FUNC(int) _PyImport_IsLazyImportsActive(PyThreadState *tstate);
+PyAPI_FUNC(int) PyImport_IsLazyImportsEnabled(void);
+#endif
+
 struct _inittab {
     const char *name;           /* ASCII encoded string */
     PyObject* (*initfunc)(void);

Include/cpython/initconfig.h

@@ -241,6 +241,10 @@ typedef struct PyConfig {
     // PYTHON_PRESITE=package.module or -X presite=package.module
     wchar_t *run_presite;
 #endif
+
+#ifdef ENABLE_LAZY_IMPORTS
+    int lazy_imports;
+#endif
 } PyConfig;
 
 PyAPI_FUNC(void) PyConfig_InitPythonConfig(PyConfig *config);

Include/cpython/pyerrors.h

@@ -130,3 +130,7 @@ PyAPI_FUNC(void) PyErr_FormatUnraisable(const char *, ...);
 PyAPI_DATA(PyObject *) PyExc_PythonFinalizationError;
 
 #define Py_FatalError(message) _Py_FatalErrorFunc(__func__, (message))
+
+#ifdef ENABLE_LAZY_IMPORTS
+PyAPI_DATA(PyObject *) PyExc_ImportCycleError;
+#endif

Include/internal/pycore_ceval.h

@@ -86,6 +86,9 @@ extern void _PyEval_Fini(void);
 
 
 extern PyObject* _PyEval_GetBuiltins(PyThreadState *tstate);
+#ifdef ENABLE_LAZY_IMPORTS
+extern PyObject* _PyEval_GetGlobals(PyThreadState *tstate);
+#endif
 
 // Trampoline API
 

Include/internal/pycore_compile.h

@@ -150,6 +150,10 @@ int _PyCompile_ResolveNameop(struct _PyCompiler *c, PyObject *mangled, int scope
 int _PyCompile_IsInteractiveTopLevel(struct _PyCompiler *c);
 int _PyCompile_IsInInlinedComp(struct _PyCompiler *c);
 int _PyCompile_ScopeType(struct _PyCompiler *c);
+#ifdef ENABLE_LAZY_IMPORTS
+int _PyCompile_NFBlocks(struct _PyCompiler *c);
+int _PyCompile_CFFlags(struct _PyCompiler *c);
+#endif
 int _PyCompile_OptimizationLevel(struct _PyCompiler *c);
 int _PyCompile_LookupArg(struct _PyCompiler *c, PyCodeObject *co, PyObject *name);
 PyObject *_PyCompile_Qualname(struct _PyCompiler *c);

Include/internal/pycore_dict.h

@@ -110,6 +110,13 @@ extern void _PyDictKeys_DecRef(PyDictKeysObject *keys);
  * -1 when no entry found, -3 when compare raises error.
  */
 extern Py_ssize_t _Py_dict_lookup(PyDictObject *mp, PyObject *key, Py_hash_t hash, PyObject **value_addr);
+
+#ifdef ENABLE_LAZY_IMPORTS
+/* _Py_dict_lookup_keep_lazy() is the same as _Py_dict_lookup(), but keeps lazy objects unresolved */
+extern Py_ssize_t _Py_dict_lookup_keep_lazy(PyDictObject *mp, PyObject *key, Py_hash_t hash, PyObject **value_addr);
+extern int _PyDict_GetItemRefKeepLazy(PyObject *, PyObject *, PyObject **);
+#endif
+
 extern Py_ssize_t _Py_dict_lookup_threadsafe(PyDictObject *mp, PyObject *key, Py_hash_t hash, PyObject **value_addr);
 extern Py_ssize_t _Py_dict_lookup_threadsafe_stackref(PyDictObject *mp, PyObject *key, Py_hash_t hash, _PyStackRef *value_addr);
 
@@ -160,6 +167,9 @@ PyAPI_FUNC(void) _PyDict_EnsureSharedOnRead(PyDictObject *mp);
 #define DKIX_DUMMY (-2)  /* Used internally */
 #define DKIX_ERROR (-3)
 #define DKIX_KEY_CHANGED (-4) /* Used internally */
+#ifdef ENABLE_LAZY_IMPORTS
+#define DKIX_VALUE_ERROR (-5) /* Used internally */
+#endif
 
 typedef enum {
     DICT_KEYS_GENERAL = 0,
@@ -178,7 +188,14 @@ struct _dictkeysobject {
     uint8_t dk_log2_index_bytes;
 
     /* Kind of keys */
+#ifdef ENABLE_LAZY_IMPORTS
+    uint8_t dk_kind: 7;
+
+    /* Contains lazy imports. Assume there are lazy import objects unless otherwise specified. */
+    uint8_t dk_lazy_imports : 1;
+#else
     uint8_t dk_kind;
+#endif
 
 #ifdef Py_GIL_DISABLED
     /* Lock used to protect shared keys */