From 330c527299a5380f39c658bfa9321706cabc445d Mon Sep 17 00:00:00 2001
From: Richard Hansen <rhansen@rhansen.org>
Date: Sat, 12 Oct 2024 16:57:27 -0400
Subject: [PATCH] gh-124872: Change PyContext_WatchCallback to take PyObject
 (#124737)

The PyContext struct is not intended to be public, and users of the
API don't need anything more specific than PyObject.  Also see
gh-78943.
---
 Doc/c-api/contextvars.rst    |  2 +-
 Include/cpython/context.h    |  2 +-
 Modules/_testcapi/watchers.c | 10 +++++-----
 Python/context.c             |  6 +++---
 4 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/Doc/c-api/contextvars.rst b/Doc/c-api/contextvars.rst
index 59e74ba1ac7..8eba54a80dc 100644
--- a/Doc/c-api/contextvars.rst
+++ b/Doc/c-api/contextvars.rst
@@ -136,7 +136,7 @@ Context object management functions:
 
    .. versionadded:: 3.14
 
-.. c:type:: int (*PyContext_WatchCallback)(PyContextEvent event, PyContext* ctx)
+.. c:type:: int (*PyContext_WatchCallback)(PyContextEvent event, PyObject *obj)
 
    Context object watcher callback function.  The object passed to the callback
    is event-specific; see :c:type:`PyContextEvent` for details.
diff --git a/Include/cpython/context.h b/Include/cpython/context.h
index d722b4d9313..3c9be7873b9 100644
--- a/Include/cpython/context.h
+++ b/Include/cpython/context.h
@@ -52,7 +52,7 @@ typedef enum {
  * if the callback returns with an exception set, it must return -1. Otherwise
  * it should return 0
  */
-typedef int (*PyContext_WatchCallback)(PyContextEvent, PyContext *);
+typedef int (*PyContext_WatchCallback)(PyContextEvent, PyObject *);
 
 /*
  * Register a per-interpreter callback that will be invoked for context object
diff --git a/Modules/_testcapi/watchers.c b/Modules/_testcapi/watchers.c
index 689863d098a..b4233d07134 100644
--- a/Modules/_testcapi/watchers.c
+++ b/Modules/_testcapi/watchers.c
@@ -630,7 +630,7 @@ static int num_context_object_enter_events[NUM_CONTEXT_WATCHERS] = {0, 0};
 static int num_context_object_exit_events[NUM_CONTEXT_WATCHERS] = {0, 0};
 
 static int
-handle_context_watcher_event(int which_watcher, PyContextEvent event, PyContext *ctx) {
+handle_context_watcher_event(int which_watcher, PyContextEvent event, PyObject *ctx) {
     if (event == Py_CONTEXT_EVENT_ENTER) {
         num_context_object_enter_events[which_watcher]++;
     }
@@ -644,22 +644,22 @@ handle_context_watcher_event(int which_watcher, PyContextEvent event, PyContext
 }
 
 static int
-first_context_watcher_callback(PyContextEvent event, PyContext *ctx) {
+first_context_watcher_callback(PyContextEvent event, PyObject *ctx) {
     return handle_context_watcher_event(0, event, ctx);
 }
 
 static int
-second_context_watcher_callback(PyContextEvent event, PyContext *ctx) {
+second_context_watcher_callback(PyContextEvent event, PyObject *ctx) {
     return handle_context_watcher_event(1, event, ctx);
 }
 
 static int
-noop_context_event_handler(PyContextEvent event, PyContext *ctx) {
+noop_context_event_handler(PyContextEvent event, PyObject *ctx) {
     return 0;
 }
 
 static int
-error_context_event_handler(PyContextEvent event, PyContext *ctx) {
+error_context_event_handler(PyContextEvent event, PyObject *ctx) {
     PyErr_SetString(PyExc_RuntimeError, "boom!");
     return -1;
 }
diff --git a/Python/context.c b/Python/context.c
index 9b742136b07..8bc487a33c8 100644
--- a/Python/context.c
+++ b/Python/context.c
@@ -113,7 +113,7 @@ context_event_name(PyContextEvent event) {
 }
 
 static void
-notify_context_watchers(PyThreadState *ts, PyContextEvent event, PyContext *ctx)
+notify_context_watchers(PyThreadState *ts, PyContextEvent event, PyObject *ctx)
 {
     assert(Py_REFCNT(ctx) > 0);
     PyInterpreterState *interp = ts->interp;
@@ -193,7 +193,7 @@ _PyContext_Enter(PyThreadState *ts, PyObject *octx)
     ts->context = Py_NewRef(ctx);
     ts->context_ver++;
 
-    notify_context_watchers(ts, Py_CONTEXT_EVENT_ENTER, ctx);
+    notify_context_watchers(ts, Py_CONTEXT_EVENT_ENTER, octx);
     return 0;
 }
 
@@ -227,7 +227,7 @@ _PyContext_Exit(PyThreadState *ts, PyObject *octx)
         return -1;
     }
 
-    notify_context_watchers(ts, Py_CONTEXT_EVENT_EXIT, ctx);
+    notify_context_watchers(ts, Py_CONTEXT_EVENT_EXIT, octx);
     Py_SETREF(ts->context, (PyObject *)ctx->ctx_prev);
     ts->context_ver++;