From 79511398d144139dd0aaf587466f59af43db3efc Mon Sep 17 00:00:00 2001
From: Eric Snow <ericsnowcurrently@gmail.com>
Date: Fri, 1 Feb 2019 15:45:29 -0700
Subject: [PATCH 1/8] Add 2 PyInterpreterState getters.

---
 Include/cpython/pystate.h |  4 ++++
 Python/pystate.c          | 11 +++++++++++
 2 files changed, 15 insertions(+)

diff --git a/Include/cpython/pystate.h b/Include/cpython/pystate.h
index 78e9a5ed1013d8..b4079e5ed5dedb 100644
--- a/Include/cpython/pystate.h
+++ b/Include/cpython/pystate.h
@@ -88,6 +88,10 @@ typedef struct _is {
     uint64_t tstate_next_unique_id;
 } PyInterpreterState;
 
+PyAPI_FUNC(_PyCoreConfig *) _PyInterpreterState_GetCoreConfig(struct _is *);
+PyAPI_FUNC(_PyMainInterpreterConfig *) _PyInterpreterState_GetMainConfig(struct _is *);
+
+
 /* State unique per thread */
 
 /* Py_tracefunc return -1 when raising an exception, or 0 for success. */
diff --git a/Python/pystate.c b/Python/pystate.c
index 4dc3b81e4cdb97..a5aaba07060747 100644
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -404,6 +404,17 @@ _PyInterpreterState_IDDecref(PyInterpreterState *interp)
     }
 }
 
+_PyCoreConfig *
+_PyInterpreterState_GetCoreConfig(PyInterpreterState *interp)
+{
+    return &interp->core_config;
+}
+
+_PyMainInterpreterConfig *
+_PyInterpreterState_GetMainConfig(PyInterpreterState *interp)
+{
+    return &interp->config;
+}
 
 /* Default implementation for _PyThreadState_GetFrame */
 static struct _frame *

From f37e6c1d83a474af6dd914637c7e84139a37b9f9 Mon Sep 17 00:00:00 2001
From: Eric Snow <ericsnowcurrently@gmail.com>
Date: Fri, 1 Feb 2019 15:45:06 -0700
Subject: [PATCH 2/8] Move PyInterpreterState to the internal header file.

---
 Include/cpython/pystate.h         |  78 ++++-------------------
 Include/import.h                  |   4 ++
 Include/internal/pycore_pystate.h | 100 ++++++++++++++++++++++++------
 Include/traceback.h               |   3 +
 Modules/_testcapimodule.c         |   4 +-
 5 files changed, 101 insertions(+), 88 deletions(-)

diff --git a/Include/cpython/pystate.h b/Include/cpython/pystate.h
index b4079e5ed5dedb..ee934c6982411b 100644
--- a/Include/cpython/pystate.h
+++ b/Include/cpython/pystate.h
@@ -6,8 +6,6 @@
 extern "C" {
 #endif
 
-typedef PyObject* (*_PyFrameEvalFunction)(struct _frame *, int);
-
 /* Placeholders while working on the new configuration API
  *
  * See PEP 432 for final anticipated contents
@@ -30,63 +28,11 @@ typedef struct {
     (_PyMainInterpreterConfig){.install_signal_handlers = -1}
 /* Note: _PyMainInterpreterConfig_INIT sets other fields to 0/NULL */
 
-typedef struct _is {
-
-    struct _is *next;
-    struct _ts *tstate_head;
-
-    int64_t id;
-    int64_t id_refcount;
-    PyThread_type_lock id_mutex;
-
-    PyObject *modules;
-    PyObject *modules_by_index;
-    PyObject *sysdict;
-    PyObject *builtins;
-    PyObject *importlib;
-
-    /* Used in Python/sysmodule.c. */
-    int check_interval;
-
-    /* Used in Modules/_threadmodule.c. */
-    long num_threads;
-    /* Support for runtime thread stack size tuning.
-       A value of 0 means using the platform's default stack size
-       or the size specified by the THREAD_STACK_SIZE macro. */
-    /* Used in Python/thread.c. */
-    size_t pythread_stacksize;
-
-    PyObject *codec_search_path;
-    PyObject *codec_search_cache;
-    PyObject *codec_error_registry;
-    int codecs_initialized;
-    int fscodec_initialized;
-
-    _PyCoreConfig core_config;
-    _PyMainInterpreterConfig config;
-#ifdef HAVE_DLOPEN
-    int dlopenflags;
-#endif
-
-    PyObject *builtins_copy;
-    PyObject *import_func;
-    /* Initialized to PyEval_EvalFrameDefault(). */
-    _PyFrameEvalFunction eval_frame;
-
-    Py_ssize_t co_extra_user_count;
-    freefunc co_extra_freefuncs[MAX_CO_EXTRA_USERS];
-
-#ifdef HAVE_FORK
-    PyObject *before_forkers;
-    PyObject *after_forkers_parent;
-    PyObject *after_forkers_child;
+#if !defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_BUILTIN)
+typedef struct _is PyInterpreterState;
+#else
+/* PyInterpreterState is defined in internal/pycore_pystate.h */
 #endif
-    /* AtExit module */
-    void (*pyexitfunc)(PyObject *);
-    PyObject *pyexitmodule;
-
-    uint64_t tstate_next_unique_id;
-} PyInterpreterState;
 
 PyAPI_FUNC(_PyCoreConfig *) _PyInterpreterState_GetCoreConfig(struct _is *);
 PyAPI_FUNC(_PyMainInterpreterConfig *) _PyInterpreterState_GetMainConfig(struct _is *);
@@ -131,7 +77,7 @@ typedef struct _ts {
 
     struct _ts *prev;
     struct _ts *next;
-    PyInterpreterState *interp;
+    struct _is *interp;
 
     struct _frame *frame;
     int recursion_depth;
@@ -226,11 +172,11 @@ typedef struct _ts {
    interpreter. It cannot return NULL.
 
    The caller must hold the GIL.*/
-PyAPI_FUNC(PyInterpreterState *) _PyInterpreterState_Get(void);
+PyAPI_FUNC(struct _is *) _PyInterpreterState_Get(void);
 
 PyAPI_FUNC(int) _PyState_AddModule(PyObject*, struct PyModuleDef*);
 PyAPI_FUNC(void) _PyState_ClearModules(void);
-PyAPI_FUNC(PyThreadState *) _PyThreadState_Prealloc(PyInterpreterState *);
+PyAPI_FUNC(PyThreadState *) _PyThreadState_Prealloc(struct _is *);
 PyAPI_FUNC(void) _PyThreadState_Init(PyThreadState *);
 PyAPI_FUNC(void) _PyThreadState_DeleteExcept(PyThreadState *tstate);
 PyAPI_FUNC(void) _PyGILState_Reinit(void);
@@ -254,7 +200,7 @@ PyAPI_FUNC(int) PyGILState_Check(void);
    is called and after _PyGILState_Fini() is called.
 
    See also _PyInterpreterState_Get() and _PyInterpreterState_GET_UNSAFE(). */
-PyAPI_FUNC(PyInterpreterState *) _PyGILState_GetInterpreterStateUnsafe(void);
+PyAPI_FUNC(struct _is *) _PyGILState_GetInterpreterStateUnsafe(void);
 
 /* The implementation of sys._current_frames()  Returns a dict mapping
    thread id to that thread's current frame.
@@ -263,10 +209,10 @@ PyAPI_FUNC(PyObject *) _PyThread_CurrentFrames(void);
 
 /* Routines for advanced debuggers, requested by David Beazley.
    Don't use unless you know what you are doing! */
-PyAPI_FUNC(PyInterpreterState *) PyInterpreterState_Main(void);
-PyAPI_FUNC(PyInterpreterState *) PyInterpreterState_Head(void);
-PyAPI_FUNC(PyInterpreterState *) PyInterpreterState_Next(PyInterpreterState *);
-PyAPI_FUNC(PyThreadState *) PyInterpreterState_ThreadHead(PyInterpreterState *);
+PyAPI_FUNC(struct _is *) PyInterpreterState_Main(void);
+PyAPI_FUNC(struct _is *) PyInterpreterState_Head(void);
+PyAPI_FUNC(struct _is *) PyInterpreterState_Next(struct _is *);
+PyAPI_FUNC(PyThreadState *) PyInterpreterState_ThreadHead(struct _is *);
 PyAPI_FUNC(PyThreadState *) PyThreadState_Next(PyThreadState *);
 
 typedef struct _frame *(*PyThreadFrameGetter)(PyThreadState *self_);
diff --git a/Include/import.h b/Include/import.h
index c664803478a551..30066c170dc1b0 100644
--- a/Include/import.h
+++ b/Include/import.h
@@ -7,6 +7,10 @@
 extern "C" {
 #endif
 
+#if defined(Py_BUILD_CORE) || defined(Py_BUILD_CORE_BUILTIN)
+#include "internal/pycore_pystate.h"
+#endif
+
 #ifndef Py_LIMITED_API
 PyAPI_FUNC(_PyInitError) _PyImportZip_Init(void);
 
diff --git a/Include/internal/pycore_pystate.h b/Include/internal/pycore_pystate.h
index 4f5545aaa45fab..370efe83cba350 100644
--- a/Include/internal/pycore_pystate.h
+++ b/Include/internal/pycore_pystate.h
@@ -17,31 +17,67 @@ extern "C" {
 #include "pycore_warnings.h"
 
 
-/* GIL state */
+/* interpreter state */
 
-struct _gilstate_runtime_state {
-    int check_enabled;
-    /* Assuming the current thread holds the GIL, this is the
-       PyThreadState for the current thread. */
-    _Py_atomic_address tstate_current;
-    PyThreadFrameGetter getframe;
-    /* The single PyInterpreterState used by this process'
-       GILState implementation
-    */
-    /* TODO: Given interp_main, it may be possible to kill this ref */
-    PyInterpreterState *autoInterpreterState;
-    Py_tss_t autoTSSkey;
-};
+typedef PyObject* (*_PyFrameEvalFunction)(struct _frame *, int);
 
-/* hook for PyEval_GetFrame(), requested for Psyco */
-#define _PyThreadState_GetFrame _PyRuntime.gilstate.getframe
+typedef struct _is {
 
-/* Issue #26558: Flag to disable PyGILState_Check().
-   If set to non-zero, PyGILState_Check() always return 1. */
-#define _PyGILState_check_enabled _PyRuntime.gilstate.check_enabled
+    struct _is *next;
+    struct _ts *tstate_head;
 
+    int64_t id;
+    int64_t id_refcount;
+    PyThread_type_lock id_mutex;
 
-/* interpreter state */
+    PyObject *modules;
+    PyObject *modules_by_index;
+    PyObject *sysdict;
+    PyObject *builtins;
+    PyObject *importlib;
+
+    /* Used in Python/sysmodule.c. */
+    int check_interval;
+
+    /* Used in Modules/_threadmodule.c. */
+    long num_threads;
+    /* Support for runtime thread stack size tuning.
+       A value of 0 means using the platform's default stack size
+       or the size specified by the THREAD_STACK_SIZE macro. */
+    /* Used in Python/thread.c. */
+    size_t pythread_stacksize;
+
+    PyObject *codec_search_path;
+    PyObject *codec_search_cache;
+    PyObject *codec_error_registry;
+    int codecs_initialized;
+    int fscodec_initialized;
+
+    _PyCoreConfig core_config;
+    _PyMainInterpreterConfig config;
+#ifdef HAVE_DLOPEN
+    int dlopenflags;
+#endif
+
+    PyObject *builtins_copy;
+    PyObject *import_func;
+    /* Initialized to PyEval_EvalFrameDefault(). */
+    _PyFrameEvalFunction eval_frame;
+
+    Py_ssize_t co_extra_user_count;
+    freefunc co_extra_freefuncs[MAX_CO_EXTRA_USERS];
+
+#ifdef HAVE_FORK
+    PyObject *before_forkers;
+    PyObject *after_forkers_parent;
+    PyObject *after_forkers_child;
+#endif
+    /* AtExit module */
+    void (*pyexitfunc)(PyObject *);
+    PyObject *pyexitmodule;
+
+    uint64_t tstate_next_unique_id;
+} PyInterpreterState;
 
 PyAPI_FUNC(PyInterpreterState *) _PyInterpreterState_LookUpID(PY_INT64_T);
 
@@ -119,6 +155,30 @@ struct _xidregitem {
 };
 
 
+/* GIL state */
+
+struct _gilstate_runtime_state {
+    int check_enabled;
+    /* Assuming the current thread holds the GIL, this is the
+       PyThreadState for the current thread. */
+    _Py_atomic_address tstate_current;
+    PyThreadFrameGetter getframe;
+    /* The single PyInterpreterState used by this process'
+       GILState implementation
+    */
+    /* TODO: Given interp_main, it may be possible to kill this ref */
+    PyInterpreterState *autoInterpreterState;
+    Py_tss_t autoTSSkey;
+};
+
+/* hook for PyEval_GetFrame(), requested for Psyco */
+#define _PyThreadState_GetFrame _PyRuntime.gilstate.getframe
+
+/* Issue #26558: Flag to disable PyGILState_Check().
+   If set to non-zero, PyGILState_Check() always return 1. */
+#define _PyGILState_check_enabled _PyRuntime.gilstate.check_enabled
+
+
 /* Full Python runtime state */
 
 typedef struct pyruntimestate {
diff --git a/Include/traceback.h b/Include/traceback.h
index b5874100f477a5..161645ca58e3f5 100644
--- a/Include/traceback.h
+++ b/Include/traceback.h
@@ -5,6 +5,9 @@
 extern "C" {
 #endif
 
+#if defined(Py_BUILD_CORE) || defined(Py_BUILD_CORE_BUILTIN)
+#include "internal/pycore_pystate.h"
+#endif
 #include "pystate.h"
 
 struct _frame;
diff --git a/Modules/_testcapimodule.c b/Modules/_testcapimodule.c
index 85810f30b1c528..350ef771630eab 100644
--- a/Modules/_testcapimodule.c
+++ b/Modules/_testcapimodule.c
@@ -4685,7 +4685,7 @@ static PyObject *
 get_core_config(PyObject *self, PyObject *Py_UNUSED(args))
 {
     PyInterpreterState *interp = _PyInterpreterState_Get();
-    const _PyCoreConfig *config = &interp->core_config;
+    const _PyCoreConfig *config = _PyInterpreterState_GetCoreConfig(interp);
     return _PyCoreConfig_AsDict(config);
 }
 
@@ -4694,7 +4694,7 @@ static PyObject *
 get_main_config(PyObject *self, PyObject *Py_UNUSED(args))
 {
     PyInterpreterState *interp = _PyInterpreterState_Get();
-    const _PyMainInterpreterConfig *config = &interp->config;
+    const _PyMainInterpreterConfig *config = _PyInterpreterState_GetMainConfig(interp);
     return _PyMainInterpreterConfig_AsDict(config);
 }
 

From 51b1941dab2f9ead1596e58087cc9adcdf79326e Mon Sep 17 00:00:00 2001
From: Eric Snow <ericsnowcurrently@gmail.com>
Date: Fri, 1 Feb 2019 18:24:30 -0700
Subject: [PATCH 3/8] Add a NEWS entry.

---
 Doc/whatsnew/3.8.rst                                   | 10 ++++++++++
 .../2019-02-01-18-12-14.bpo-35886.0Z-C0V.rst           |  2 ++
 2 files changed, 12 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Core and Builtins/2019-02-01-18-12-14.bpo-35886.0Z-C0V.rst

diff --git a/Doc/whatsnew/3.8.rst b/Doc/whatsnew/3.8.rst
index 370ef4604834f4..60c31e3c8afe1f 100644
--- a/Doc/whatsnew/3.8.rst
+++ b/Doc/whatsnew/3.8.rst
@@ -475,6 +475,16 @@ Changes in the Python API
 * ``PyGC_Head`` struct is changed completely.  All code touched the
   struct member should be rewritten.  (See :issue:`33597`)
 
+* The ``PyInterpreterState`` struct has been moved into the "internal"
+  header files (specifically Include/internal/pycore_pystate.h).  An
+  opaque ``PyInterpreterState`` is still available as part of the public
+  API (and stable ABI).  The docs indicate that none of the struct's
+  fields are public, so we hope no one has been using them.  However,
+  if you do rely on one or more of those private fields and have no
+  alternative then please open a BPO issue.  We'll work on helping
+  you adjust (possibly including adding accessor functions to the
+  public API).  (See :issue:`35886`.)
+
 * Asyncio tasks can now be named, either by passing the ``name`` keyword
   argument to :func:`asyncio.create_task` or
   the :meth:`~asyncio.loop.create_task` event loop method, or by
diff --git a/Misc/NEWS.d/next/Core and Builtins/2019-02-01-18-12-14.bpo-35886.0Z-C0V.rst b/Misc/NEWS.d/next/Core and Builtins/2019-02-01-18-12-14.bpo-35886.0Z-C0V.rst
new file mode 100644
index 00000000000000..362a7a61d46ffc
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2019-02-01-18-12-14.bpo-35886.0Z-C0V.rst	
@@ -0,0 +1,2 @@
+The implementation of PyInterpreterState has been moved into the internal
+header files (guarded by Py_BUILD_CORE).

From 5801b60a2ef93a5c653866f58c7faf03160b9b96 Mon Sep 17 00:00:00 2001
From: Eric Snow <ericsnowcurrently@gmail.com>
Date: Fri, 8 Feb 2019 13:30:02 -0700
Subject: [PATCH 4/8] Fix the includes.

---
 Include/import.h    | 2 +-
 Include/traceback.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/Include/import.h b/Include/import.h
index 30066c170dc1b0..8ea3f623261652 100644
--- a/Include/import.h
+++ b/Include/import.h
@@ -8,7 +8,7 @@ extern "C" {
 #endif
 
 #if defined(Py_BUILD_CORE) || defined(Py_BUILD_CORE_BUILTIN)
-#include "internal/pycore_pystate.h"
+#include "pycore_pystate.h"
 #endif
 
 #ifndef Py_LIMITED_API
diff --git a/Include/traceback.h b/Include/traceback.h
index 161645ca58e3f5..4d0b96cfaf3b59 100644
--- a/Include/traceback.h
+++ b/Include/traceback.h
@@ -6,7 +6,7 @@ extern "C" {
 #endif
 
 #if defined(Py_BUILD_CORE) || defined(Py_BUILD_CORE_BUILTIN)
-#include "internal/pycore_pystate.h"
+#include "pycore_pystate.h"
 #endif
 #include "pystate.h"
 

From 76bac2119c43405605bc22aaab357aca639f20bf Mon Sep 17 00:00:00 2001
From: Eric Snow <ericsnowcurrently@gmail.com>
Date: Fri, 8 Feb 2019 17:26:35 -0700
Subject: [PATCH 5/8] Always typedef PyInterpreterState in Include/pystate.h.

---
 Include/cpython/pystate.h         | 25 +++++++++++--------------
 Include/import.h                  |  4 ----
 Include/internal/pycore_pystate.h | 13 +++++++------
 Include/pystate.h                 | 15 ++++++++-------
 Include/traceback.h               |  3 ---
 5 files changed, 26 insertions(+), 34 deletions(-)

diff --git a/Include/cpython/pystate.h b/Include/cpython/pystate.h
index ee934c6982411b..283af0e8ade1fc 100644
--- a/Include/cpython/pystate.h
+++ b/Include/cpython/pystate.h
@@ -28,14 +28,11 @@ typedef struct {
     (_PyMainInterpreterConfig){.install_signal_handlers = -1}
 /* Note: _PyMainInterpreterConfig_INIT sets other fields to 0/NULL */
 
-#if !defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_BUILTIN)
-typedef struct _is PyInterpreterState;
-#else
 /* PyInterpreterState is defined in internal/pycore_pystate.h */
-#endif
+//typedef struct _is PyInterpreterState;
 
-PyAPI_FUNC(_PyCoreConfig *) _PyInterpreterState_GetCoreConfig(struct _is *);
-PyAPI_FUNC(_PyMainInterpreterConfig *) _PyInterpreterState_GetMainConfig(struct _is *);
+PyAPI_FUNC(_PyCoreConfig *) _PyInterpreterState_GetCoreConfig(PyInterpreterState *);
+PyAPI_FUNC(_PyMainInterpreterConfig *) _PyInterpreterState_GetMainConfig(PyInterpreterState *);
 
 
 /* State unique per thread */
@@ -77,7 +74,7 @@ typedef struct _ts {
 
     struct _ts *prev;
     struct _ts *next;
-    struct _is *interp;
+    PyInterpreterState *interp;
 
     struct _frame *frame;
     int recursion_depth;
@@ -172,11 +169,11 @@ typedef struct _ts {
    interpreter. It cannot return NULL.
 
    The caller must hold the GIL.*/
-PyAPI_FUNC(struct _is *) _PyInterpreterState_Get(void);
+PyAPI_FUNC(PyInterpreterState *) _PyInterpreterState_Get(void);
 
 PyAPI_FUNC(int) _PyState_AddModule(PyObject*, struct PyModuleDef*);
 PyAPI_FUNC(void) _PyState_ClearModules(void);
-PyAPI_FUNC(PyThreadState *) _PyThreadState_Prealloc(struct _is *);
+PyAPI_FUNC(PyThreadState *) _PyThreadState_Prealloc(PyInterpreterState *);
 PyAPI_FUNC(void) _PyThreadState_Init(PyThreadState *);
 PyAPI_FUNC(void) _PyThreadState_DeleteExcept(PyThreadState *tstate);
 PyAPI_FUNC(void) _PyGILState_Reinit(void);
@@ -200,7 +197,7 @@ PyAPI_FUNC(int) PyGILState_Check(void);
    is called and after _PyGILState_Fini() is called.
 
    See also _PyInterpreterState_Get() and _PyInterpreterState_GET_UNSAFE(). */
-PyAPI_FUNC(struct _is *) _PyGILState_GetInterpreterStateUnsafe(void);
+PyAPI_FUNC(PyInterpreterState *) _PyGILState_GetInterpreterStateUnsafe(void);
 
 /* The implementation of sys._current_frames()  Returns a dict mapping
    thread id to that thread's current frame.
@@ -209,10 +206,10 @@ PyAPI_FUNC(PyObject *) _PyThread_CurrentFrames(void);
 
 /* Routines for advanced debuggers, requested by David Beazley.
    Don't use unless you know what you are doing! */
-PyAPI_FUNC(struct _is *) PyInterpreterState_Main(void);
-PyAPI_FUNC(struct _is *) PyInterpreterState_Head(void);
-PyAPI_FUNC(struct _is *) PyInterpreterState_Next(struct _is *);
-PyAPI_FUNC(PyThreadState *) PyInterpreterState_ThreadHead(struct _is *);
+PyAPI_FUNC(PyInterpreterState *) PyInterpreterState_Main(void);
+PyAPI_FUNC(PyInterpreterState *) PyInterpreterState_Head(void);
+PyAPI_FUNC(PyInterpreterState *) PyInterpreterState_Next(PyInterpreterState *);
+PyAPI_FUNC(PyThreadState *) PyInterpreterState_ThreadHead(PyInterpreterState *);
 PyAPI_FUNC(PyThreadState *) PyThreadState_Next(PyThreadState *);
 
 typedef struct _frame *(*PyThreadFrameGetter)(PyThreadState *self_);
diff --git a/Include/import.h b/Include/import.h
index 8ea3f623261652..c664803478a551 100644
--- a/Include/import.h
+++ b/Include/import.h
@@ -7,10 +7,6 @@
 extern "C" {
 #endif
 
-#if defined(Py_BUILD_CORE) || defined(Py_BUILD_CORE_BUILTIN)
-#include "pycore_pystate.h"
-#endif
-
 #ifndef Py_LIMITED_API
 PyAPI_FUNC(_PyInitError) _PyImportZip_Init(void);
 
diff --git a/Include/internal/pycore_pystate.h b/Include/internal/pycore_pystate.h
index 370efe83cba350..7796223b59e650 100644
--- a/Include/internal/pycore_pystate.h
+++ b/Include/internal/pycore_pystate.h
@@ -21,7 +21,8 @@ extern "C" {
 
 typedef PyObject* (*_PyFrameEvalFunction)(struct _frame *, int);
 
-typedef struct _is {
+// The PyInterpreterState typedef is in Include/pystate.h.
+struct _is {
 
     struct _is *next;
     struct _ts *tstate_head;
@@ -77,13 +78,13 @@ typedef struct _is {
     PyObject *pyexitmodule;
 
     uint64_t tstate_next_unique_id;
-} PyInterpreterState;
+};
 
-PyAPI_FUNC(PyInterpreterState *) _PyInterpreterState_LookUpID(PY_INT64_T);
+PyAPI_FUNC(struct _is*) _PyInterpreterState_LookUpID(PY_INT64_T);
 
-PyAPI_FUNC(int) _PyInterpreterState_IDInitref(PyInterpreterState *);
-PyAPI_FUNC(void) _PyInterpreterState_IDIncref(PyInterpreterState *);
-PyAPI_FUNC(void) _PyInterpreterState_IDDecref(PyInterpreterState *);
+PyAPI_FUNC(int) _PyInterpreterState_IDInitref(struct _is *);
+PyAPI_FUNC(void) _PyInterpreterState_IDIncref(struct _is *);
+PyAPI_FUNC(void) _PyInterpreterState_IDDecref(struct _is *);
 
 
 /* cross-interpreter data */
diff --git a/Include/pystate.h b/Include/pystate.h
index ba5e9883306a70..02a0643d74c2e7 100644
--- a/Include/pystate.h
+++ b/Include/pystate.h
@@ -20,22 +20,23 @@ struct _frame;
 struct _ts;
 struct _is;
 
+/* struct _is is defined in internal/pycore_pystate.h */
+typedef struct _is PyInterpreterState;
 #ifdef Py_LIMITED_API
 typedef struct _ts PyThreadState;
-typedef struct _is PyInterpreterState;
 #else
-/* PyThreadState and PyInterpreterState are defined in cpython/pystate.h */
+/* PyThreadState is defined in cpython/pystate.h */
 #endif
 
 /* State unique per thread */
 
-PyAPI_FUNC(struct _is *) PyInterpreterState_New(void);
-PyAPI_FUNC(void) PyInterpreterState_Clear(struct _is *);
-PyAPI_FUNC(void) PyInterpreterState_Delete(struct _is *);
+PyAPI_FUNC(PyInterpreterState *) PyInterpreterState_New(void);
+PyAPI_FUNC(void) PyInterpreterState_Clear(PyInterpreterState *);
+PyAPI_FUNC(void) PyInterpreterState_Delete(PyInterpreterState *);
 
 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03070000
 /* New in 3.7 */
-PyAPI_FUNC(int64_t) PyInterpreterState_GetID(struct _is *);
+PyAPI_FUNC(int64_t) PyInterpreterState_GetID(PyInterpreterState *);
 #endif
 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03030000
 /* New in 3.3 */
@@ -44,7 +45,7 @@ PyAPI_FUNC(int) PyState_RemoveModule(struct PyModuleDef*);
 #endif
 PyAPI_FUNC(PyObject*) PyState_FindModule(struct PyModuleDef*);
 
-PyAPI_FUNC(struct _ts *) PyThreadState_New(struct _is *);
+PyAPI_FUNC(struct _ts *) PyThreadState_New(PyInterpreterState *);
 PyAPI_FUNC(void) PyThreadState_Clear(struct _ts *);
 PyAPI_FUNC(void) PyThreadState_Delete(struct _ts *);
 PyAPI_FUNC(void) PyThreadState_DeleteCurrent(void);
diff --git a/Include/traceback.h b/Include/traceback.h
index 4d0b96cfaf3b59..b5874100f477a5 100644
--- a/Include/traceback.h
+++ b/Include/traceback.h
@@ -5,9 +5,6 @@
 extern "C" {
 #endif
 
-#if defined(Py_BUILD_CORE) || defined(Py_BUILD_CORE_BUILTIN)
-#include "pycore_pystate.h"
-#endif
 #include "pystate.h"
 
 struct _frame;

From f2d776c44f0636a3c43c10e53d635cd37d1ed8c1 Mon Sep 17 00:00:00 2001
From: Eric Snow <ericsnowcurrently@gmail.com>
Date: Fri, 8 Feb 2019 17:34:36 -0700
Subject: [PATCH 6/8] Always typedef PyThreadState in Include/pystate.h.

---
 Include/cpython/pystate.h |  5 +++--
 Include/pystate.h         | 20 ++++++++------------
 2 files changed, 11 insertions(+), 14 deletions(-)

diff --git a/Include/cpython/pystate.h b/Include/cpython/pystate.h
index 283af0e8ade1fc..d8dc4a121a9874 100644
--- a/Include/cpython/pystate.h
+++ b/Include/cpython/pystate.h
@@ -69,7 +69,8 @@ typedef struct _err_stackitem {
 } _PyErr_StackItem;
 
 
-typedef struct _ts {
+// The PyThreadState typedef is in Include/pystate.h.
+struct _ts {
     /* See Python/ceval.c for comments explaining most fields */
 
     struct _ts *prev;
@@ -161,7 +162,7 @@ typedef struct _ts {
 
     /* XXX signal handlers should also be here */
 
-} PyThreadState;
+};
 
 /* Get the current interpreter state.
 
diff --git a/Include/pystate.h b/Include/pystate.h
index 02a0643d74c2e7..4e1613b60c7982 100644
--- a/Include/pystate.h
+++ b/Include/pystate.h
@@ -20,13 +20,9 @@ struct _frame;
 struct _ts;
 struct _is;
 
-/* struct _is is defined in internal/pycore_pystate.h */
-typedef struct _is PyInterpreterState;
-#ifdef Py_LIMITED_API
+/* struct _is and struct _ts are defined in internal/pycore_pystate.h */
 typedef struct _ts PyThreadState;
-#else
-/* PyThreadState is defined in cpython/pystate.h */
-#endif
+typedef struct _is PyInterpreterState;
 
 /* State unique per thread */
 
@@ -45,9 +41,9 @@ PyAPI_FUNC(int) PyState_RemoveModule(struct PyModuleDef*);
 #endif
 PyAPI_FUNC(PyObject*) PyState_FindModule(struct PyModuleDef*);
 
-PyAPI_FUNC(struct _ts *) PyThreadState_New(PyInterpreterState *);
-PyAPI_FUNC(void) PyThreadState_Clear(struct _ts *);
-PyAPI_FUNC(void) PyThreadState_Delete(struct _ts *);
+PyAPI_FUNC(PyThreadState *) PyThreadState_New(PyInterpreterState *);
+PyAPI_FUNC(void) PyThreadState_Clear(PyThreadState *);
+PyAPI_FUNC(void) PyThreadState_Delete(PyThreadState *);
 PyAPI_FUNC(void) PyThreadState_DeleteCurrent(void);
 
 /* Get the current thread state.
@@ -58,7 +54,7 @@ PyAPI_FUNC(void) PyThreadState_DeleteCurrent(void);
    The caller must hold the GIL.
 
    See also PyThreadState_GET() and _PyThreadState_GET(). */
-PyAPI_FUNC(struct _ts *) PyThreadState_Get(void);
+PyAPI_FUNC(PyThreadState *) PyThreadState_Get(void);
 
 /* Get the current Python thread state.
 
@@ -71,7 +67,7 @@ PyAPI_FUNC(struct _ts *) PyThreadState_Get(void);
    See also PyThreadState_Get() and _PyThreadState_GET(). */
 #define PyThreadState_GET() PyThreadState_Get()
 
-PyAPI_FUNC(struct _ts *) PyThreadState_Swap(struct _ts *);
+PyAPI_FUNC(PyThreadState *) PyThreadState_Swap(PyThreadState *);
 PyAPI_FUNC(PyObject *) PyThreadState_GetDict(void);
 PyAPI_FUNC(int) PyThreadState_SetAsyncExc(unsigned long, PyObject *);
 
@@ -119,7 +115,7 @@ PyAPI_FUNC(void) PyGILState_Release(PyGILState_STATE);
    thread-state, even if no auto-thread-state call has been made
    on the main thread.
 */
-PyAPI_FUNC(struct _ts *) PyGILState_GetThisThreadState(void);
+PyAPI_FUNC(PyThreadState *) PyGILState_GetThisThreadState(void);
 
 
 #ifndef Py_LIMITED_API

From 64658fc34ebf5eee1e7ff3a2ea8d15cb062db0dc Mon Sep 17 00:00:00 2001
From: Eric Snow <ericsnowcurrently@gmail.com>
Date: Fri, 8 Feb 2019 17:57:43 -0700
Subject: [PATCH 7/8] Fix _testembed.c.

---
 Programs/_testembed.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Programs/_testembed.c b/Programs/_testembed.c
index 22212bff52d4a1..e28d94c175e6a5 100644
--- a/Programs/_testembed.c
+++ b/Programs/_testembed.c
@@ -315,7 +315,7 @@ dump_config_impl(void)
 
     /* core config */
     PyInterpreterState *interp = _PyInterpreterState_Get();
-    const _PyCoreConfig *core_config = &interp->core_config;
+    const _PyCoreConfig *core_config = _PyInterpreterState_GetCoreConfig(interp);
     dict = _PyCoreConfig_AsDict(core_config);
     if (dict == NULL) {
         goto error;
@@ -326,7 +326,7 @@ dump_config_impl(void)
     Py_CLEAR(dict);
 
     /* main config */
-    const _PyMainInterpreterConfig *main_config = &interp->config;
+    const _PyMainInterpreterConfig *main_config = _PyInterpreterState_GetMainConfig(interp);
     dict = _PyMainInterpreterConfig_AsDict(main_config);
     if (dict == NULL) {
         goto error;

From c19dd546ae299ea9f6ac1f0207b93885f9d527ce Mon Sep 17 00:00:00 2001
From: Eric Snow <ericsnowcurrently@gmail.com>
Date: Mon, 18 Feb 2019 13:47:12 -0700
Subject: [PATCH 8/8] Fix some comments.

---
 Include/cpython/pystate.h | 3 ---
 Include/pystate.h         | 3 ++-
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/Include/cpython/pystate.h b/Include/cpython/pystate.h
index d8dc4a121a9874..0da59d96d1f75e 100644
--- a/Include/cpython/pystate.h
+++ b/Include/cpython/pystate.h
@@ -28,9 +28,6 @@ typedef struct {
     (_PyMainInterpreterConfig){.install_signal_handlers = -1}
 /* Note: _PyMainInterpreterConfig_INIT sets other fields to 0/NULL */
 
-/* PyInterpreterState is defined in internal/pycore_pystate.h */
-//typedef struct _is PyInterpreterState;
-
 PyAPI_FUNC(_PyCoreConfig *) _PyInterpreterState_GetCoreConfig(PyInterpreterState *);
 PyAPI_FUNC(_PyMainInterpreterConfig *) _PyInterpreterState_GetMainConfig(PyInterpreterState *);
 
diff --git a/Include/pystate.h b/Include/pystate.h
index 4e1613b60c7982..a541dc8f00969d 100644
--- a/Include/pystate.h
+++ b/Include/pystate.h
@@ -20,8 +20,9 @@ struct _frame;
 struct _ts;
 struct _is;
 
-/* struct _is and struct _ts are defined in internal/pycore_pystate.h */
+/* struct _ts is defined in cpython/pystate.h */
 typedef struct _ts PyThreadState;
+/* struct _is is defined in internal/pycore_pystate.h */
 typedef struct _is PyInterpreterState;
 
 /* State unique per thread */