Use Python "Limited API" in PL/Python

From 0e046101ea8ed321a09b0ed2bb0a0fc0ce0d2399 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Mon, 2 Dec 2024 08:53:42 +0100
Subject: [PATCH 1/3] Remove obsolete Python version check

The checked version is already the current minimum supported version
(3.2).
---
 src/pl/plpython/plpy_exec.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/src/pl/plpython/plpy_exec.c b/src/pl/plpython/plpy_exec.c
index 0e84bb90829..00747bb811b 100644
--- a/src/pl/plpython/plpy_exec.c
+++ b/src/pl/plpython/plpy_exec.c
@@ -1066,13 +1066,7 @@ PLy_procedure_call(PLyProcedure *proc, const char *kargs, PyObject *vargs)
 
 	PG_TRY();
 	{
-#if PY_VERSION_HEX >= 0x03020000
-		rv = PyEval_EvalCode(proc->code,
-							 proc->globals, proc->globals);
-#else
-		rv = PyEval_EvalCode((PyCodeObject *) proc->code,
-							 proc->globals, proc->globals);
-#endif
+		rv = PyEval_EvalCode(proc->code, proc->globals, proc->globals);
 
 		/*
 		 * Since plpy will only let you close subtransactions that you
-- 
2.39.5 (Apple Git-154)

From f2e0b87a5bae68756327b37959812674dcd02668 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Mon, 2 Dec 2024 08:53:42 +0100
Subject: [PATCH 2/3] Use Python "Limited API" in PL/Python

This allows building PL/Python against any Python 3.x version and
using another Python 3.x version at run time.

Implementation details:

- Convert static types to heap types
  (https://docs.python.org/3/howto/isolating-extensions.html#heap-types).

- Replace PyRun_String() with component functions.

- Replace PyList_SET_ITEM() with PyList_SetItem().
---
 src/pl/plpython/plpy_cursorobject.c  | 71 +++++++++++++-------
 src/pl/plpython/plpy_planobject.c    | 61 +++++++++++------
 src/pl/plpython/plpy_procedure.c     |  5 +-
 src/pl/plpython/plpy_resultobject.c  | 98 +++++++++++++++++-----------
 src/pl/plpython/plpy_subxactobject.c | 41 +++++++-----
 src/pl/plpython/plpy_typeio.c        |  6 +-
 src/pl/plpython/plpython.h           |  2 +
 7 files changed, 179 insertions(+), 105 deletions(-)

diff --git a/src/pl/plpython/plpy_cursorobject.c b/src/pl/plpython/plpy_cursorobject.c
index bb3fa8a3909..2a370157f90 100644
--- a/src/pl/plpython/plpy_cursorobject.c
+++ b/src/pl/plpython/plpy_cursorobject.c
@@ -20,7 +20,7 @@
 #include "utils/memutils.h"
 
 static PyObject *PLy_cursor_query(const char *query);
-static void PLy_cursor_dealloc(PyObject *arg);
+static void PLy_cursor_dealloc(PLyCursorObject *self);
 static PyObject *PLy_cursor_iternext(PyObject *self);
 static PyObject *PLy_cursor_fetch(PyObject *self, PyObject *args);
 static PyObject *PLy_cursor_close(PyObject *self, PyObject *unused);
@@ -33,22 +33,43 @@ static PyMethodDef PLy_cursor_methods[] = {
 	{NULL, NULL, 0, NULL}
 };
 
-static PyTypeObject PLy_CursorType = {
-	PyVarObject_HEAD_INIT(NULL, 0)
-	.tp_name = "PLyCursor",
-	.tp_basicsize = sizeof(PLyCursorObject),
-	.tp_dealloc = PLy_cursor_dealloc,
-	.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
-	.tp_doc = PLy_cursor_doc,
-	.tp_iter = PyObject_SelfIter,
-	.tp_iternext = PLy_cursor_iternext,
-	.tp_methods = PLy_cursor_methods,
+static PyType_Slot PLyCursor_slots[] =
+{
+	{
+		Py_tp_dealloc, PLy_cursor_dealloc
+	},
+	{
+		Py_tp_doc, (char *) PLy_cursor_doc
+	},
+	{
+		Py_tp_iter, PyObject_SelfIter
+	},
+	{
+		Py_tp_iternext, PLy_cursor_iternext
+	},
+	{
+		Py_tp_methods, PLy_cursor_methods
+	},
+	{
+		0, NULL
+	}
 };
 
+static PyType_Spec PLyCursor_spec =
+{
+	.name = "PLyCursor",
+		.basicsize = sizeof(PLyCursorObject),
+		.flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
+		.slots = PLyCursor_slots,
+};
+
+static PyTypeObject *PLy_CursorType;
+
 void
 PLy_cursor_init_type(void)
 {
-	if (PyType_Ready(&PLy_CursorType) < 0)
+	PLy_CursorType = (PyTypeObject *) PyType_FromSpec(&PLyCursor_spec);
+	if (!PLy_CursorType)
 		elog(ERROR, "could not initialize PLy_CursorType");
 }
 
@@ -80,7 +101,7 @@ PLy_cursor_query(const char *query)
 	volatile MemoryContext oldcontext;
 	volatile ResourceOwner oldowner;
 
-	if ((cursor = PyObject_New(PLyCursorObject, &PLy_CursorType)) == NULL)
+	if ((cursor = PyObject_New(PLyCursorObject, PLy_CursorType)) == NULL)
 		return NULL;
 	cursor->portalname = NULL;
 	cursor->closed = false;
@@ -177,7 +198,7 @@ PLy_cursor_plan(PyObject *ob, PyObject *args)
 		return NULL;
 	}
 
-	if ((cursor = PyObject_New(PLyCursorObject, &PLy_CursorType)) == NULL)
+	if ((cursor = PyObject_New(PLyCursorObject, PLy_CursorType)) == NULL)
 		return NULL;
 	cursor->portalname = NULL;
 	cursor->closed = false;
@@ -272,30 +293,30 @@ PLy_cursor_plan(PyObject *ob, PyObject *args)
 }
 
 static void
-PLy_cursor_dealloc(PyObject *arg)
+PLy_cursor_dealloc(PLyCursorObject *self)
 {
-	PLyCursorObject *cursor;
+	PyTypeObject *tp = Py_TYPE(self);
 	Portal		portal;
 
-	cursor = (PLyCursorObject *) arg;
-
-	if (!cursor->closed)
+	if (!self->closed)
 	{
-		portal = GetPortalByName(cursor->portalname);
+		portal = GetPortalByName(self->portalname);
 
 		if (PortalIsValid(portal))
 		{
 			UnpinPortal(portal);
 			SPI_cursor_close(portal);
 		}
-		cursor->closed = true;
+		self->closed = true;
 	}
-	if (cursor->mcxt)
+	if (self->mcxt)
 	{
-		MemoryContextDelete(cursor->mcxt);
-		cursor->mcxt = NULL;
+		MemoryContextDelete(self->mcxt);
+		self->mcxt = NULL;
 	}
-	arg->ob_type->tp_free(arg);
+
+	PyObject_Free(self);
+	Py_DECREF(tp);
 }
 
 static PyObject *
diff --git a/src/pl/plpython/plpy_planobject.c b/src/pl/plpython/plpy_planobject.c
index 9427674d2f4..1b97b5cbd2a 100644
--- a/src/pl/plpython/plpy_planobject.c
+++ b/src/pl/plpython/plpy_planobject.c
@@ -12,7 +12,7 @@
 #include "plpython.h"
 #include "utils/memutils.h"
 
-static void PLy_plan_dealloc(PyObject *arg);
+static void PLy_plan_dealloc(PLyPlanObject *self);
 static PyObject *PLy_plan_cursor(PyObject *self, PyObject *args);
 static PyObject *PLy_plan_execute(PyObject *self, PyObject *args);
 static PyObject *PLy_plan_status(PyObject *self, PyObject *args);
@@ -26,20 +26,37 @@ static PyMethodDef PLy_plan_methods[] = {
 	{NULL, NULL, 0, NULL}
 };
 
-static PyTypeObject PLy_PlanType = {
-	PyVarObject_HEAD_INIT(NULL, 0)
-	.tp_name = "PLyPlan",
-	.tp_basicsize = sizeof(PLyPlanObject),
-	.tp_dealloc = PLy_plan_dealloc,
-	.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
-	.tp_doc = PLy_plan_doc,
-	.tp_methods = PLy_plan_methods,
+static PyType_Slot PLyPlan_slots[] =
+{
+	{
+		Py_tp_dealloc, PLy_plan_dealloc
+	},
+	{
+		Py_tp_doc, (char *) PLy_plan_doc
+	},
+	{
+		Py_tp_methods, PLy_plan_methods
+	},
+	{
+		0, NULL
+	}
 };
 
+static PyType_Spec PLyPlan_spec =
+{
+	.name = "PLyPlan",
+		.basicsize = sizeof(PLyPlanObject),
+		.flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
+		.slots = PLyPlan_slots,
+};
+
+static PyTypeObject *PLy_PlanType;
+
 void
 PLy_plan_init_type(void)
 {
-	if (PyType_Ready(&PLy_PlanType) < 0)
+	PLy_PlanType = (PyTypeObject *) PyType_FromSpec(&PLyPlan_spec);
+	if (!PLy_PlanType)
 		elog(ERROR, "could not initialize PLy_PlanType");
 }
 
@@ -48,7 +65,7 @@ PLy_plan_new(void)
 {
 	PLyPlanObject *ob;
 
-	if ((ob = PyObject_New(PLyPlanObject, &PLy_PlanType)) == NULL)
+	if ((ob = PyObject_New(PLyPlanObject, PLy_PlanType)) == NULL)
 		return NULL;
 
 	ob->plan = NULL;
@@ -63,25 +80,27 @@ PLy_plan_new(void)
 bool
 is_PLyPlanObject(PyObject *ob)
 {
-	return ob->ob_type == &PLy_PlanType;
+	return ob->ob_type == PLy_PlanType;
 }
 
 static void
-PLy_plan_dealloc(PyObject *arg)
+PLy_plan_dealloc(PLyPlanObject *self)
 {
-	PLyPlanObject *ob = (PLyPlanObject *) arg;
+	PyTypeObject *tp = Py_TYPE(self);
 
-	if (ob->plan)
+	if (self->plan)
 	{
-		SPI_freeplan(ob->plan);
-		ob->plan = NULL;
+		SPI_freeplan(self->plan);
+		self->plan = NULL;
 	}
-	if (ob->mcxt)
+	if (self->mcxt)
 	{
-		MemoryContextDelete(ob->mcxt);
-		ob->mcxt = NULL;
+		MemoryContextDelete(self->mcxt);
+		self->mcxt = NULL;
 	}
-	arg->ob_type->tp_free(arg);
+
+	PyObject_Free(self);
+	Py_DECREF(tp);
 }
 
 
diff --git a/src/pl/plpython/plpy_procedure.c b/src/pl/plpython/plpy_procedure.c
index c35a3b801ab..b494eeb474f 100644
--- a/src/pl/plpython/plpy_procedure.c
+++ b/src/pl/plpython/plpy_procedure.c
@@ -350,6 +350,7 @@ PLy_procedure_compile(PLyProcedure *proc, const char *src)
 {
 	PyObject   *crv = NULL;
 	char	   *msrc;
+	PyObject   *code0;
 
 	proc->globals = PyDict_Copy(PLy_interp_globals);
 
@@ -368,7 +369,9 @@ PLy_procedure_compile(PLyProcedure *proc, const char *src)
 	msrc = PLy_procedure_munge_source(proc->pyname, src);
 	/* Save the mangled source for later inclusion in tracebacks */
 	proc->src = MemoryContextStrdup(proc->mcxt, msrc);
-	crv = PyRun_String(msrc, Py_file_input, proc->globals, NULL);
+	code0 = Py_CompileString(msrc, "<string>", Py_file_input);
+	if (code0)
+		crv = PyEval_EvalCode(code0, proc->globals, NULL);
 	pfree(msrc);
 
 	if (crv != NULL)
diff --git a/src/pl/plpython/plpy_resultobject.c b/src/pl/plpython/plpy_resultobject.c
index 95acce65493..f2628205669 100644
--- a/src/pl/plpython/plpy_resultobject.c
+++ b/src/pl/plpython/plpy_resultobject.c
@@ -10,7 +10,7 @@
 #include "plpy_resultobject.h"
 #include "plpython.h"
 
-static void PLy_result_dealloc(PyObject *arg);
+static void PLy_result_dealloc(PLyResultObject *self);
 static PyObject *PLy_result_colnames(PyObject *self, PyObject *unused);
 static PyObject *PLy_result_coltypes(PyObject *self, PyObject *unused);
 static PyObject *PLy_result_coltypmods(PyObject *self, PyObject *unused);
@@ -24,17 +24,6 @@ static int	PLy_result_ass_subscript(PyObject *arg, PyObject *item, PyObject *val
 
 static char PLy_result_doc[] = "Results of a PostgreSQL query";
 
-static PySequenceMethods PLy_result_as_sequence = {
-	.sq_length = PLy_result_length,
-	.sq_item = PLy_result_item,
-};
-
-static PyMappingMethods PLy_result_as_mapping = {
-	.mp_length = PLy_result_length,
-	.mp_subscript = PLy_result_subscript,
-	.mp_ass_subscript = PLy_result_ass_subscript,
-};
-
 static PyMethodDef PLy_result_methods[] = {
 	{"colnames", PLy_result_colnames, METH_NOARGS, NULL},
 	{"coltypes", PLy_result_coltypes, METH_NOARGS, NULL},
@@ -44,23 +33,55 @@ static PyMethodDef PLy_result_methods[] = {
 	{NULL, NULL, 0, NULL}
 };
 
-static PyTypeObject PLy_ResultType = {
-	PyVarObject_HEAD_INIT(NULL, 0)
-	.tp_name = "PLyResult",
-	.tp_basicsize = sizeof(PLyResultObject),
-	.tp_dealloc = PLy_result_dealloc,
-	.tp_as_sequence = &PLy_result_as_sequence,
-	.tp_as_mapping = &PLy_result_as_mapping,
-	.tp_str = &PLy_result_str,
-	.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
-	.tp_doc = PLy_result_doc,
-	.tp_methods = PLy_result_methods,
+static PyType_Slot PLyResult_slots[] =
+{
+	{
+		Py_tp_dealloc, PLy_result_dealloc
+	},
+	{
+		Py_sq_length, PLy_result_length
+	},
+	{
+		Py_sq_item, PLy_result_item
+	},
+	{
+		Py_mp_length, PLy_result_length
+	},
+	{
+		Py_mp_subscript, PLy_result_subscript
+	},
+	{
+		Py_mp_ass_subscript, PLy_result_ass_subscript
+	},
+	{
+		Py_tp_str, PLy_result_str
+	},
+	{
+		Py_tp_doc, (char *) PLy_result_doc
+	},
+	{
+		Py_tp_methods, PLy_result_methods
+	},
+	{
+		0, NULL
+	}
 };
 
+static PyType_Spec PLyResult_spec =
+{
+	.name = "PLyResult",
+		.basicsize = sizeof(PLyResultObject),
+		.flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
+		.slots = PLyResult_slots,
+};
+
+static PyTypeObject *PLy_ResultType;
+
 void
 PLy_result_init_type(void)
 {
-	if (PyType_Ready(&PLy_ResultType) < 0)
+	PLy_ResultType = (PyTypeObject *) PyType_FromSpec(&PLyResult_spec);
+	if (!PLy_ResultType)
 		elog(ERROR, "could not initialize PLy_ResultType");
 }
 
@@ -69,7 +90,7 @@ PLy_result_new(void)
 {
 	PLyResultObject *ob;
 
-	if ((ob = PyObject_New(PLyResultObject, &PLy_ResultType)) == NULL)
+	if ((ob = PyObject_New(PLyResultObject, PLy_ResultType)) == NULL)
 		return NULL;
 
 	/* ob->tuples = NULL; */
@@ -89,20 +110,21 @@ PLy_result_new(void)
 }
 
 static void
-PLy_result_dealloc(PyObject *arg)
+PLy_result_dealloc(PLyResultObject *self)
 {
-	PLyResultObject *ob = (PLyResultObject *) arg;
+	PyTypeObject *tp = Py_TYPE(self);
 
-	Py_XDECREF(ob->nrows);
-	Py_XDECREF(ob->rows);
-	Py_XDECREF(ob->status);
-	if (ob->tupdesc)
+	Py_XDECREF(self->nrows);
+	Py_XDECREF(self->rows);
+	Py_XDECREF(self->status);
+	if (self->tupdesc)
 	{
-		FreeTupleDesc(ob->tupdesc);
-		ob->tupdesc = NULL;
+		FreeTupleDesc(self->tupdesc);
+		self->tupdesc = NULL;
 	}
 
-	arg->ob_type->tp_free(arg);
+	PyObject_Free(self);
+	Py_DECREF(tp);
 }
 
 static PyObject *
@@ -125,7 +147,7 @@ PLy_result_colnames(PyObject *self, PyObject *unused)
 	{
 		Form_pg_attribute attr = TupleDescAttr(ob->tupdesc, i);
 
-		PyList_SET_ITEM(list, i, PLyUnicode_FromString(NameStr(attr->attname)));
+		PyList_SetItem(list, i, PLyUnicode_FromString(NameStr(attr->attname)));
 	}
 
 	return list;
@@ -151,7 +173,7 @@ PLy_result_coltypes(PyObject *self, PyObject *unused)
 	{
 		Form_pg_attribute attr = TupleDescAttr(ob->tupdesc, i);
 
-		PyList_SET_ITEM(list, i, PyLong_FromLong(attr->atttypid));
+		PyList_SetItem(list, i, PyLong_FromLong(attr->atttypid));
 	}
 
 	return list;
@@ -177,7 +199,7 @@ PLy_result_coltypmods(PyObject *self, PyObject *unused)
 	{
 		Form_pg_attribute attr = TupleDescAttr(ob->tupdesc, i);
 
-		PyList_SET_ITEM(list, i, PyLong_FromLong(attr->atttypmod));
+		PyList_SetItem(list, i, PyLong_FromLong(attr->atttypmod));
 	}
 
 	return list;
@@ -227,7 +249,7 @@ PLy_result_str(PyObject *arg)
 	PLyResultObject *ob = (PLyResultObject *) arg;
 
 	return PyUnicode_FromFormat("<%s status=%S nrows=%S rows=%S>",
-								Py_TYPE(ob)->tp_name,
+								"PLyResult",
 								ob->status,
 								ob->nrows,
 								ob->rows);
diff --git a/src/pl/plpython/plpy_subxactobject.c b/src/pl/plpython/plpy_subxactobject.c
index 5c92a0e089a..cc7ff3f9df7 100644
--- a/src/pl/plpython/plpy_subxactobject.c
+++ b/src/pl/plpython/plpy_subxactobject.c
@@ -15,7 +15,6 @@
 List	   *explicit_subtransactions = NIL;
 
 
-static void PLy_subtransaction_dealloc(PyObject *subxact);
 static PyObject *PLy_subtransaction_enter(PyObject *self, PyObject *unused);
 static PyObject *PLy_subtransaction_exit(PyObject *self, PyObject *args);
 
@@ -31,21 +30,35 @@ static PyMethodDef PLy_subtransaction_methods[] = {
 	{NULL, NULL, 0, NULL}
 };
 
-static PyTypeObject PLy_SubtransactionType = {
-	PyVarObject_HEAD_INIT(NULL, 0)
-	.tp_name = "PLySubtransaction",
-	.tp_basicsize = sizeof(PLySubtransactionObject),
-	.tp_dealloc = PLy_subtransaction_dealloc,
-	.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
-	.tp_doc = PLy_subtransaction_doc,
-	.tp_methods = PLy_subtransaction_methods,
+static PyType_Slot PLySubtransaction_slots[] =
+{
+	{
+		Py_tp_doc, (char *) PLy_subtransaction_doc
+	},
+	{
+		Py_tp_methods, PLy_subtransaction_methods
+	},
+	{
+		0, NULL
+	}
+};
+
+static PyType_Spec PLySubtransaction_spec =
+{
+	.name = "PLySubtransaction",
+		.basicsize = sizeof(PLySubtransactionObject),
+		.flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
+		.slots = PLySubtransaction_slots,
 };
 
+static PyTypeObject *PLy_SubtransactionType;
+
 
 void
 PLy_subtransaction_init_type(void)
 {
-	if (PyType_Ready(&PLy_SubtransactionType) < 0)
+	PLy_SubtransactionType = (PyTypeObject *) PyType_FromSpec(&PLySubtransaction_spec);
+	if (!PLy_SubtransactionType)
 		elog(ERROR, "could not initialize PLy_SubtransactionType");
 }
 
@@ -55,7 +68,7 @@ PLy_subtransaction_new(PyObject *self, PyObject *unused)
 {
 	PLySubtransactionObject *ob;
 
-	ob = PyObject_New(PLySubtransactionObject, &PLy_SubtransactionType);
+	ob = PyObject_New(PLySubtransactionObject, PLy_SubtransactionType);
 
 	if (ob == NULL)
 		return NULL;
@@ -66,12 +79,6 @@ PLy_subtransaction_new(PyObject *self, PyObject *unused)
 	return (PyObject *) ob;
 }
 
-/* Python requires a dealloc function to be defined */
-static void
-PLy_subtransaction_dealloc(PyObject *subxact)
-{
-}
-
 /*
  * subxact.__enter__() or subxact.enter()
  *
diff --git a/src/pl/plpython/plpy_typeio.c b/src/pl/plpython/plpy_typeio.c
index db14c5f8dae..27d9b2f1af6 100644
--- a/src/pl/plpython/plpy_typeio.c
+++ b/src/pl/plpython/plpy_typeio.c
@@ -723,7 +723,7 @@ PLyList_FromArray_recurse(PLyDatumToOb *elm, int *dims, int ndim, int dim,
 
 			sublist = PLyList_FromArray_recurse(elm, dims, ndim, dim + 1,
 												dataptr_p, bitmap_p, bitmask_p);
-			PyList_SET_ITEM(list, i, sublist);
+			PyList_SetItem(list, i, sublist);
 		}
 	}
 	else
@@ -742,14 +742,14 @@ PLyList_FromArray_recurse(PLyDatumToOb *elm, int *dims, int ndim, int dim,
 			if (bitmap && (*bitmap & bitmask) == 0)
 			{
 				Py_INCREF(Py_None);
-				PyList_SET_ITEM(list, i, Py_None);
+				PyList_SetItem(list, i, Py_None);
 			}
 			else
 			{
 				Datum		itemvalue;
 
 				itemvalue = fetch_att(dataptr, elm->typbyval, elm->typlen);
-				PyList_SET_ITEM(list, i, elm->func(elm, itemvalue));
+				PyList_SetItem(list, i, elm->func(elm, itemvalue));
 				dataptr = att_addlength_pointer(dataptr, elm->typlen, dataptr);
 				dataptr = (char *) att_align_nominal(dataptr, elm->typalign);
 			}
diff --git a/src/pl/plpython/plpython.h b/src/pl/plpython/plpython.h
index ec822577260..c933419a347 100644
--- a/src/pl/plpython/plpython.h
+++ b/src/pl/plpython/plpython.h
@@ -19,6 +19,8 @@
 #error Python.h must be included via plpython.h
 #endif
 
+#define Py_LIMITED_API 0x03020000
+
 /*
  * Pull in Python headers via a wrapper header, to control the scope of
  * the system_header pragma therein.
-- 
2.39.5 (Apple Git-154)

From e4d30a4b7e0ede113cf83e98e3210c3a947451eb Mon Sep 17 00:00:00 2001
From: Jakob Egger <jakob@eggerapps.at>
Date: Tue, 14 Jan 2025 16:31:44 +0100
Subject: [PATCH 3/3] Attempt to fix meson build for PL/Python with limited API

---
 meson.build | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/meson.build b/meson.build
index cfd654d2916..ff31221e4ee 100644
--- a/meson.build
+++ b/meson.build
@@ -1146,6 +1146,10 @@ if not pyopt.disabled()
   python3_inst = pm.find_installation(python.path(), required: pyopt)
   if python3_inst.found()
     python3_dep = python3_inst.dependency(embed: true, required: pyopt)
+    python3_dep = declare_dependency(
+        dependencies: python3_dep,
+        compile_args: '-DPy_LIMITED_API='0x03020000',
+    )
     # Remove this check after we depend on Meson >= 1.1.0
     if not cc.check_header('Python.h', dependencies: python3_dep, required: pyopt, include_directories: postgres_inc)
       python3_dep = not_found_dep
-- 
2.39.5 (Apple Git-154)

From 1a981b3979391c75c1b5a9cd686e7e0c14cd58b6 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Mon, 2 Dec 2024 08:53:42 +0100
Subject: [PATCH v2 1/3] Remove obsolete Python version check

The checked version is already the current minimum supported version
(3.2).

Discussion: https://www.postgresql.org/message-id/flat/ee410de1-1e0b-4770-b125-eeefd4726a24@eisentraut.org
---
 src/pl/plpython/plpy_exec.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/src/pl/plpython/plpy_exec.c b/src/pl/plpython/plpy_exec.c
index 0e84bb90829..00747bb811b 100644
--- a/src/pl/plpython/plpy_exec.c
+++ b/src/pl/plpython/plpy_exec.c
@@ -1066,13 +1066,7 @@ PLy_procedure_call(PLyProcedure *proc, const char *kargs, PyObject *vargs)
 
 	PG_TRY();
 	{
-#if PY_VERSION_HEX >= 0x03020000
-		rv = PyEval_EvalCode(proc->code,
-							 proc->globals, proc->globals);
-#else
-		rv = PyEval_EvalCode((PyCodeObject *) proc->code,
-							 proc->globals, proc->globals);
-#endif
+		rv = PyEval_EvalCode(proc->code, proc->globals, proc->globals);
 
 		/*
 		 * Since plpy will only let you close subtransactions that you

base-commit: d5221c49a302ee7f3964449cbc730b01ce4e7d40
-- 
2.47.1

From c921ee3dcae83c489d2963537fcf9e1965004312 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Wed, 15 Jan 2025 22:09:29 +0100
Subject: [PATCH v2 2/3] Prepare for Python "Limited API" in PL/Python

Using the Python Limited API would allow building PL/Python against
any Python 3.x version and using another Python 3.x version at run
time.  This commit does not activate that, but it prepares the code to
only use APIs supported by the Limited API.

Implementation details:

- Convert static types to heap types
  (https://docs.python.org/3/howto/isolating-extensions.html#heap-types).

- Replace PyRun_String() with component functions.

- Replace PyList_SET_ITEM() with PyList_SetItem().

Discussion: https://www.postgresql.org/message-id/flat/ee410de1-1e0b-4770-b125-eeefd4726a24@eisentraut.org
---
 src/pl/plpython/plpy_cursorobject.c  | 71 +++++++++++++-------
 src/pl/plpython/plpy_planobject.c    | 61 +++++++++++------
 src/pl/plpython/plpy_procedure.c     |  5 +-
 src/pl/plpython/plpy_resultobject.c  | 98 +++++++++++++++++-----------
 src/pl/plpython/plpy_subxactobject.c | 41 +++++++-----
 src/pl/plpython/plpy_typeio.c        |  6 +-
 6 files changed, 177 insertions(+), 105 deletions(-)

diff --git a/src/pl/plpython/plpy_cursorobject.c b/src/pl/plpython/plpy_cursorobject.c
index bb3fa8a3909..2a370157f90 100644
--- a/src/pl/plpython/plpy_cursorobject.c
+++ b/src/pl/plpython/plpy_cursorobject.c
@@ -20,7 +20,7 @@
 #include "utils/memutils.h"
 
 static PyObject *PLy_cursor_query(const char *query);
-static void PLy_cursor_dealloc(PyObject *arg);
+static void PLy_cursor_dealloc(PLyCursorObject *self);
 static PyObject *PLy_cursor_iternext(PyObject *self);
 static PyObject *PLy_cursor_fetch(PyObject *self, PyObject *args);
 static PyObject *PLy_cursor_close(PyObject *self, PyObject *unused);
@@ -33,22 +33,43 @@ static PyMethodDef PLy_cursor_methods[] = {
 	{NULL, NULL, 0, NULL}
 };
 
-static PyTypeObject PLy_CursorType = {
-	PyVarObject_HEAD_INIT(NULL, 0)
-	.tp_name = "PLyCursor",
-	.tp_basicsize = sizeof(PLyCursorObject),
-	.tp_dealloc = PLy_cursor_dealloc,
-	.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
-	.tp_doc = PLy_cursor_doc,
-	.tp_iter = PyObject_SelfIter,
-	.tp_iternext = PLy_cursor_iternext,
-	.tp_methods = PLy_cursor_methods,
+static PyType_Slot PLyCursor_slots[] =
+{
+	{
+		Py_tp_dealloc, PLy_cursor_dealloc
+	},
+	{
+		Py_tp_doc, (char *) PLy_cursor_doc
+	},
+	{
+		Py_tp_iter, PyObject_SelfIter
+	},
+	{
+		Py_tp_iternext, PLy_cursor_iternext
+	},
+	{
+		Py_tp_methods, PLy_cursor_methods
+	},
+	{
+		0, NULL
+	}
 };
 
+static PyType_Spec PLyCursor_spec =
+{
+	.name = "PLyCursor",
+		.basicsize = sizeof(PLyCursorObject),
+		.flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
+		.slots = PLyCursor_slots,
+};
+
+static PyTypeObject *PLy_CursorType;
+
 void
 PLy_cursor_init_type(void)
 {
-	if (PyType_Ready(&PLy_CursorType) < 0)
+	PLy_CursorType = (PyTypeObject *) PyType_FromSpec(&PLyCursor_spec);
+	if (!PLy_CursorType)
 		elog(ERROR, "could not initialize PLy_CursorType");
 }
 
@@ -80,7 +101,7 @@ PLy_cursor_query(const char *query)
 	volatile MemoryContext oldcontext;
 	volatile ResourceOwner oldowner;
 
-	if ((cursor = PyObject_New(PLyCursorObject, &PLy_CursorType)) == NULL)
+	if ((cursor = PyObject_New(PLyCursorObject, PLy_CursorType)) == NULL)
 		return NULL;
 	cursor->portalname = NULL;
 	cursor->closed = false;
@@ -177,7 +198,7 @@ PLy_cursor_plan(PyObject *ob, PyObject *args)
 		return NULL;
 	}
 
-	if ((cursor = PyObject_New(PLyCursorObject, &PLy_CursorType)) == NULL)
+	if ((cursor = PyObject_New(PLyCursorObject, PLy_CursorType)) == NULL)
 		return NULL;
 	cursor->portalname = NULL;
 	cursor->closed = false;
@@ -272,30 +293,30 @@ PLy_cursor_plan(PyObject *ob, PyObject *args)
 }
 
 static void
-PLy_cursor_dealloc(PyObject *arg)
+PLy_cursor_dealloc(PLyCursorObject *self)
 {
-	PLyCursorObject *cursor;
+	PyTypeObject *tp = Py_TYPE(self);
 	Portal		portal;
 
-	cursor = (PLyCursorObject *) arg;
-
-	if (!cursor->closed)
+	if (!self->closed)
 	{
-		portal = GetPortalByName(cursor->portalname);
+		portal = GetPortalByName(self->portalname);
 
 		if (PortalIsValid(portal))
 		{
 			UnpinPortal(portal);
 			SPI_cursor_close(portal);
 		}
-		cursor->closed = true;
+		self->closed = true;
 	}
-	if (cursor->mcxt)
+	if (self->mcxt)
 	{
-		MemoryContextDelete(cursor->mcxt);
-		cursor->mcxt = NULL;
+		MemoryContextDelete(self->mcxt);
+		self->mcxt = NULL;
 	}
-	arg->ob_type->tp_free(arg);
+
+	PyObject_Free(self);
+	Py_DECREF(tp);
 }
 
 static PyObject *
diff --git a/src/pl/plpython/plpy_planobject.c b/src/pl/plpython/plpy_planobject.c
index 9427674d2f4..1b97b5cbd2a 100644
--- a/src/pl/plpython/plpy_planobject.c
+++ b/src/pl/plpython/plpy_planobject.c
@@ -12,7 +12,7 @@
 #include "plpython.h"
 #include "utils/memutils.h"
 
-static void PLy_plan_dealloc(PyObject *arg);
+static void PLy_plan_dealloc(PLyPlanObject *self);
 static PyObject *PLy_plan_cursor(PyObject *self, PyObject *args);
 static PyObject *PLy_plan_execute(PyObject *self, PyObject *args);
 static PyObject *PLy_plan_status(PyObject *self, PyObject *args);
@@ -26,20 +26,37 @@ static PyMethodDef PLy_plan_methods[] = {
 	{NULL, NULL, 0, NULL}
 };
 
-static PyTypeObject PLy_PlanType = {
-	PyVarObject_HEAD_INIT(NULL, 0)
-	.tp_name = "PLyPlan",
-	.tp_basicsize = sizeof(PLyPlanObject),
-	.tp_dealloc = PLy_plan_dealloc,
-	.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
-	.tp_doc = PLy_plan_doc,
-	.tp_methods = PLy_plan_methods,
+static PyType_Slot PLyPlan_slots[] =
+{
+	{
+		Py_tp_dealloc, PLy_plan_dealloc
+	},
+	{
+		Py_tp_doc, (char *) PLy_plan_doc
+	},
+	{
+		Py_tp_methods, PLy_plan_methods
+	},
+	{
+		0, NULL
+	}
 };
 
+static PyType_Spec PLyPlan_spec =
+{
+	.name = "PLyPlan",
+		.basicsize = sizeof(PLyPlanObject),
+		.flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
+		.slots = PLyPlan_slots,
+};
+
+static PyTypeObject *PLy_PlanType;
+
 void
 PLy_plan_init_type(void)
 {
-	if (PyType_Ready(&PLy_PlanType) < 0)
+	PLy_PlanType = (PyTypeObject *) PyType_FromSpec(&PLyPlan_spec);
+	if (!PLy_PlanType)
 		elog(ERROR, "could not initialize PLy_PlanType");
 }
 
@@ -48,7 +65,7 @@ PLy_plan_new(void)
 {
 	PLyPlanObject *ob;
 
-	if ((ob = PyObject_New(PLyPlanObject, &PLy_PlanType)) == NULL)
+	if ((ob = PyObject_New(PLyPlanObject, PLy_PlanType)) == NULL)
 		return NULL;
 
 	ob->plan = NULL;
@@ -63,25 +80,27 @@ PLy_plan_new(void)
 bool
 is_PLyPlanObject(PyObject *ob)
 {
-	return ob->ob_type == &PLy_PlanType;
+	return ob->ob_type == PLy_PlanType;
 }
 
 static void
-PLy_plan_dealloc(PyObject *arg)
+PLy_plan_dealloc(PLyPlanObject *self)
 {
-	PLyPlanObject *ob = (PLyPlanObject *) arg;
+	PyTypeObject *tp = Py_TYPE(self);
 
-	if (ob->plan)
+	if (self->plan)
 	{
-		SPI_freeplan(ob->plan);
-		ob->plan = NULL;
+		SPI_freeplan(self->plan);
+		self->plan = NULL;
 	}
-	if (ob->mcxt)
+	if (self->mcxt)
 	{
-		MemoryContextDelete(ob->mcxt);
-		ob->mcxt = NULL;
+		MemoryContextDelete(self->mcxt);
+		self->mcxt = NULL;
 	}
-	arg->ob_type->tp_free(arg);
+
+	PyObject_Free(self);
+	Py_DECREF(tp);
 }
 
 
diff --git a/src/pl/plpython/plpy_procedure.c b/src/pl/plpython/plpy_procedure.c
index c35a3b801ab..b494eeb474f 100644
--- a/src/pl/plpython/plpy_procedure.c
+++ b/src/pl/plpython/plpy_procedure.c
@@ -350,6 +350,7 @@ PLy_procedure_compile(PLyProcedure *proc, const char *src)
 {
 	PyObject   *crv = NULL;
 	char	   *msrc;
+	PyObject   *code0;
 
 	proc->globals = PyDict_Copy(PLy_interp_globals);
 
@@ -368,7 +369,9 @@ PLy_procedure_compile(PLyProcedure *proc, const char *src)
 	msrc = PLy_procedure_munge_source(proc->pyname, src);
 	/* Save the mangled source for later inclusion in tracebacks */
 	proc->src = MemoryContextStrdup(proc->mcxt, msrc);
-	crv = PyRun_String(msrc, Py_file_input, proc->globals, NULL);
+	code0 = Py_CompileString(msrc, "<string>", Py_file_input);
+	if (code0)
+		crv = PyEval_EvalCode(code0, proc->globals, NULL);
 	pfree(msrc);
 
 	if (crv != NULL)
diff --git a/src/pl/plpython/plpy_resultobject.c b/src/pl/plpython/plpy_resultobject.c
index 95acce65493..f2628205669 100644
--- a/src/pl/plpython/plpy_resultobject.c
+++ b/src/pl/plpython/plpy_resultobject.c
@@ -10,7 +10,7 @@
 #include "plpy_resultobject.h"
 #include "plpython.h"
 
-static void PLy_result_dealloc(PyObject *arg);
+static void PLy_result_dealloc(PLyResultObject *self);
 static PyObject *PLy_result_colnames(PyObject *self, PyObject *unused);
 static PyObject *PLy_result_coltypes(PyObject *self, PyObject *unused);
 static PyObject *PLy_result_coltypmods(PyObject *self, PyObject *unused);
@@ -24,17 +24,6 @@ static int	PLy_result_ass_subscript(PyObject *arg, PyObject *item, PyObject *val
 
 static char PLy_result_doc[] = "Results of a PostgreSQL query";
 
-static PySequenceMethods PLy_result_as_sequence = {
-	.sq_length = PLy_result_length,
-	.sq_item = PLy_result_item,
-};
-
-static PyMappingMethods PLy_result_as_mapping = {
-	.mp_length = PLy_result_length,
-	.mp_subscript = PLy_result_subscript,
-	.mp_ass_subscript = PLy_result_ass_subscript,
-};
-
 static PyMethodDef PLy_result_methods[] = {
 	{"colnames", PLy_result_colnames, METH_NOARGS, NULL},
 	{"coltypes", PLy_result_coltypes, METH_NOARGS, NULL},
@@ -44,23 +33,55 @@ static PyMethodDef PLy_result_methods[] = {
 	{NULL, NULL, 0, NULL}
 };
 
-static PyTypeObject PLy_ResultType = {
-	PyVarObject_HEAD_INIT(NULL, 0)
-	.tp_name = "PLyResult",
-	.tp_basicsize = sizeof(PLyResultObject),
-	.tp_dealloc = PLy_result_dealloc,
-	.tp_as_sequence = &PLy_result_as_sequence,
-	.tp_as_mapping = &PLy_result_as_mapping,
-	.tp_str = &PLy_result_str,
-	.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
-	.tp_doc = PLy_result_doc,
-	.tp_methods = PLy_result_methods,
+static PyType_Slot PLyResult_slots[] =
+{
+	{
+		Py_tp_dealloc, PLy_result_dealloc
+	},
+	{
+		Py_sq_length, PLy_result_length
+	},
+	{
+		Py_sq_item, PLy_result_item
+	},
+	{
+		Py_mp_length, PLy_result_length
+	},
+	{
+		Py_mp_subscript, PLy_result_subscript
+	},
+	{
+		Py_mp_ass_subscript, PLy_result_ass_subscript
+	},
+	{
+		Py_tp_str, PLy_result_str
+	},
+	{
+		Py_tp_doc, (char *) PLy_result_doc
+	},
+	{
+		Py_tp_methods, PLy_result_methods
+	},
+	{
+		0, NULL
+	}
 };
 
+static PyType_Spec PLyResult_spec =
+{
+	.name = "PLyResult",
+		.basicsize = sizeof(PLyResultObject),
+		.flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
+		.slots = PLyResult_slots,
+};
+
+static PyTypeObject *PLy_ResultType;
+
 void
 PLy_result_init_type(void)
 {
-	if (PyType_Ready(&PLy_ResultType) < 0)
+	PLy_ResultType = (PyTypeObject *) PyType_FromSpec(&PLyResult_spec);
+	if (!PLy_ResultType)
 		elog(ERROR, "could not initialize PLy_ResultType");
 }
 
@@ -69,7 +90,7 @@ PLy_result_new(void)
 {
 	PLyResultObject *ob;
 
-	if ((ob = PyObject_New(PLyResultObject, &PLy_ResultType)) == NULL)
+	if ((ob = PyObject_New(PLyResultObject, PLy_ResultType)) == NULL)
 		return NULL;
 
 	/* ob->tuples = NULL; */
@@ -89,20 +110,21 @@ PLy_result_new(void)
 }
 
 static void
-PLy_result_dealloc(PyObject *arg)
+PLy_result_dealloc(PLyResultObject *self)
 {
-	PLyResultObject *ob = (PLyResultObject *) arg;
+	PyTypeObject *tp = Py_TYPE(self);
 
-	Py_XDECREF(ob->nrows);
-	Py_XDECREF(ob->rows);
-	Py_XDECREF(ob->status);
-	if (ob->tupdesc)
+	Py_XDECREF(self->nrows);
+	Py_XDECREF(self->rows);
+	Py_XDECREF(self->status);
+	if (self->tupdesc)
 	{
-		FreeTupleDesc(ob->tupdesc);
-		ob->tupdesc = NULL;
+		FreeTupleDesc(self->tupdesc);
+		self->tupdesc = NULL;
 	}
 
-	arg->ob_type->tp_free(arg);
+	PyObject_Free(self);
+	Py_DECREF(tp);
 }
 
 static PyObject *
@@ -125,7 +147,7 @@ PLy_result_colnames(PyObject *self, PyObject *unused)
 	{
 		Form_pg_attribute attr = TupleDescAttr(ob->tupdesc, i);
 
-		PyList_SET_ITEM(list, i, PLyUnicode_FromString(NameStr(attr->attname)));
+		PyList_SetItem(list, i, PLyUnicode_FromString(NameStr(attr->attname)));
 	}
 
 	return list;
@@ -151,7 +173,7 @@ PLy_result_coltypes(PyObject *self, PyObject *unused)
 	{
 		Form_pg_attribute attr = TupleDescAttr(ob->tupdesc, i);
 
-		PyList_SET_ITEM(list, i, PyLong_FromLong(attr->atttypid));
+		PyList_SetItem(list, i, PyLong_FromLong(attr->atttypid));
 	}
 
 	return list;
@@ -177,7 +199,7 @@ PLy_result_coltypmods(PyObject *self, PyObject *unused)
 	{
 		Form_pg_attribute attr = TupleDescAttr(ob->tupdesc, i);
 
-		PyList_SET_ITEM(list, i, PyLong_FromLong(attr->atttypmod));
+		PyList_SetItem(list, i, PyLong_FromLong(attr->atttypmod));
 	}
 
 	return list;
@@ -227,7 +249,7 @@ PLy_result_str(PyObject *arg)
 	PLyResultObject *ob = (PLyResultObject *) arg;
 
 	return PyUnicode_FromFormat("<%s status=%S nrows=%S rows=%S>",
-								Py_TYPE(ob)->tp_name,
+								"PLyResult",
 								ob->status,
 								ob->nrows,
 								ob->rows);
diff --git a/src/pl/plpython/plpy_subxactobject.c b/src/pl/plpython/plpy_subxactobject.c
index 5c92a0e089a..cc7ff3f9df7 100644
--- a/src/pl/plpython/plpy_subxactobject.c
+++ b/src/pl/plpython/plpy_subxactobject.c
@@ -15,7 +15,6 @@
 List	   *explicit_subtransactions = NIL;
 
 
-static void PLy_subtransaction_dealloc(PyObject *subxact);
 static PyObject *PLy_subtransaction_enter(PyObject *self, PyObject *unused);
 static PyObject *PLy_subtransaction_exit(PyObject *self, PyObject *args);
 
@@ -31,21 +30,35 @@ static PyMethodDef PLy_subtransaction_methods[] = {
 	{NULL, NULL, 0, NULL}
 };
 
-static PyTypeObject PLy_SubtransactionType = {
-	PyVarObject_HEAD_INIT(NULL, 0)
-	.tp_name = "PLySubtransaction",
-	.tp_basicsize = sizeof(PLySubtransactionObject),
-	.tp_dealloc = PLy_subtransaction_dealloc,
-	.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
-	.tp_doc = PLy_subtransaction_doc,
-	.tp_methods = PLy_subtransaction_methods,
+static PyType_Slot PLySubtransaction_slots[] =
+{
+	{
+		Py_tp_doc, (char *) PLy_subtransaction_doc
+	},
+	{
+		Py_tp_methods, PLy_subtransaction_methods
+	},
+	{
+		0, NULL
+	}
+};
+
+static PyType_Spec PLySubtransaction_spec =
+{
+	.name = "PLySubtransaction",
+		.basicsize = sizeof(PLySubtransactionObject),
+		.flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
+		.slots = PLySubtransaction_slots,
 };
 
+static PyTypeObject *PLy_SubtransactionType;
+
 
 void
 PLy_subtransaction_init_type(void)
 {
-	if (PyType_Ready(&PLy_SubtransactionType) < 0)
+	PLy_SubtransactionType = (PyTypeObject *) PyType_FromSpec(&PLySubtransaction_spec);
+	if (!PLy_SubtransactionType)
 		elog(ERROR, "could not initialize PLy_SubtransactionType");
 }
 
@@ -55,7 +68,7 @@ PLy_subtransaction_new(PyObject *self, PyObject *unused)
 {
 	PLySubtransactionObject *ob;
 
-	ob = PyObject_New(PLySubtransactionObject, &PLy_SubtransactionType);
+	ob = PyObject_New(PLySubtransactionObject, PLy_SubtransactionType);
 
 	if (ob == NULL)
 		return NULL;
@@ -66,12 +79,6 @@ PLy_subtransaction_new(PyObject *self, PyObject *unused)
 	return (PyObject *) ob;
 }
 
-/* Python requires a dealloc function to be defined */
-static void
-PLy_subtransaction_dealloc(PyObject *subxact)
-{
-}
-
 /*
  * subxact.__enter__() or subxact.enter()
  *
diff --git a/src/pl/plpython/plpy_typeio.c b/src/pl/plpython/plpy_typeio.c
index db14c5f8dae..27d9b2f1af6 100644
--- a/src/pl/plpython/plpy_typeio.c
+++ b/src/pl/plpython/plpy_typeio.c
@@ -723,7 +723,7 @@ PLyList_FromArray_recurse(PLyDatumToOb *elm, int *dims, int ndim, int dim,
 
 			sublist = PLyList_FromArray_recurse(elm, dims, ndim, dim + 1,
 												dataptr_p, bitmap_p, bitmask_p);
-			PyList_SET_ITEM(list, i, sublist);
+			PyList_SetItem(list, i, sublist);
 		}
 	}
 	else
@@ -742,14 +742,14 @@ PLyList_FromArray_recurse(PLyDatumToOb *elm, int *dims, int ndim, int dim,
 			if (bitmap && (*bitmap & bitmask) == 0)
 			{
 				Py_INCREF(Py_None);
-				PyList_SET_ITEM(list, i, Py_None);
+				PyList_SetItem(list, i, Py_None);
 			}
 			else
 			{
 				Datum		itemvalue;
 
 				itemvalue = fetch_att(dataptr, elm->typbyval, elm->typlen);
-				PyList_SET_ITEM(list, i, elm->func(elm, itemvalue));
+				PyList_SetItem(list, i, elm->func(elm, itemvalue));
 				dataptr = att_addlength_pointer(dataptr, elm->typlen, dataptr);
 				dataptr = (char *) att_align_nominal(dataptr, elm->typalign);
 			}
-- 
2.47.1

From e059a1653a47f1ca9155a84c8f9a9f122a970ace Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Wed, 15 Jan 2025 22:22:59 +0100
Subject: [PATCH v2 3/3] Activate Python "Limited API" in PL/Python

This allows building PL/Python against any Python 3.x version and
using another Python 3.x version at run time.

Discussion: https://www.postgresql.org/message-id/flat/ee410de1-1e0b-4770-b125-eeefd4726a24@eisentraut.org
---
 src/pl/plpython/plpython.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/pl/plpython/plpython.h b/src/pl/plpython/plpython.h
index ec822577260..06fc1a5440f 100644
--- a/src/pl/plpython/plpython.h
+++ b/src/pl/plpython/plpython.h
@@ -19,6 +19,15 @@
 #error Python.h must be included via plpython.h
 #endif
 
+/*
+ * Enable Python Limited API
+ *
+ * XXX currently not enabled on MSVC because of build failures
+ */
+#if !defined(_MSC_VER)
+#define Py_LIMITED_API 0x03020000
+#endif
+
 /*
  * Pull in Python headers via a wrapper header, to control the scope of
  * the system_header pragma therein.
-- 
2.47.1

From d28601d504dff57c49089f3adcaf0dce83893d83 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Wed, 5 Mar 2025 17:38:06 +0100
Subject: [PATCH v3 1/2] Prepare for Python "Limited API" in PL/Python

Using the Python Limited API would allow building PL/Python against
any Python 3.x version and using another Python 3.x version at run
time.  This commit does not activate that, but it prepares the code to
only use APIs supported by the Limited API.

Implementation details:

- Convert static types to heap types
  (https://docs.python.org/3/howto/isolating-extensions.html#heap-types).

- Replace PyRun_String() with component functions.

- Replace PyList_SET_ITEM() with PyList_SetItem().

Discussion: https://www.postgresql.org/message-id/flat/ee410de1-1e0b-4770-b125-eeefd4726a24@eisentraut.org
---
 src/pl/plpython/plpy_cursorobject.c  |  84 +++++++++++++++------
 src/pl/plpython/plpy_planobject.c    |  70 +++++++++++------
 src/pl/plpython/plpy_procedure.c     |   5 +-
 src/pl/plpython/plpy_resultobject.c  | 109 +++++++++++++++++----------
 src/pl/plpython/plpy_subxactobject.c |  46 ++++++-----
 src/pl/plpython/plpy_typeio.c        |   6 +-
 6 files changed, 213 insertions(+), 107 deletions(-)

diff --git a/src/pl/plpython/plpy_cursorobject.c b/src/pl/plpython/plpy_cursorobject.c
index bb3fa8a3909..1c6be756120 100644
--- a/src/pl/plpython/plpy_cursorobject.c
+++ b/src/pl/plpython/plpy_cursorobject.c
@@ -20,7 +20,7 @@
 #include "utils/memutils.h"
 
 static PyObject *PLy_cursor_query(const char *query);
-static void PLy_cursor_dealloc(PyObject *arg);
+static void PLy_cursor_dealloc(PLyCursorObject *self);
 static PyObject *PLy_cursor_iternext(PyObject *self);
 static PyObject *PLy_cursor_fetch(PyObject *self, PyObject *args);
 static PyObject *PLy_cursor_close(PyObject *self, PyObject *unused);
@@ -33,22 +33,43 @@ static PyMethodDef PLy_cursor_methods[] = {
 	{NULL, NULL, 0, NULL}
 };
 
-static PyTypeObject PLy_CursorType = {
-	PyVarObject_HEAD_INIT(NULL, 0)
-	.tp_name = "PLyCursor",
-	.tp_basicsize = sizeof(PLyCursorObject),
-	.tp_dealloc = PLy_cursor_dealloc,
-	.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
-	.tp_doc = PLy_cursor_doc,
-	.tp_iter = PyObject_SelfIter,
-	.tp_iternext = PLy_cursor_iternext,
-	.tp_methods = PLy_cursor_methods,
+static PyType_Slot PLyCursor_slots[] =
+{
+	{
+		Py_tp_dealloc, PLy_cursor_dealloc
+	},
+	{
+		Py_tp_doc, (char *) PLy_cursor_doc
+	},
+	{
+		Py_tp_iter, PyObject_SelfIter
+	},
+	{
+		Py_tp_iternext, PLy_cursor_iternext
+	},
+	{
+		Py_tp_methods, PLy_cursor_methods
+	},
+	{
+		0, NULL
+	}
 };
 
+static PyType_Spec PLyCursor_spec =
+{
+	.name = "PLyCursor",
+		.basicsize = sizeof(PLyCursorObject),
+		.flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
+		.slots = PLyCursor_slots,
+};
+
+static PyTypeObject *PLy_CursorType;
+
 void
 PLy_cursor_init_type(void)
 {
-	if (PyType_Ready(&PLy_CursorType) < 0)
+	PLy_CursorType = (PyTypeObject *) PyType_FromSpec(&PLyCursor_spec);
+	if (!PLy_CursorType)
 		elog(ERROR, "could not initialize PLy_CursorType");
 }
 
@@ -80,8 +101,12 @@ PLy_cursor_query(const char *query)
 	volatile MemoryContext oldcontext;
 	volatile ResourceOwner oldowner;
 
-	if ((cursor = PyObject_New(PLyCursorObject, &PLy_CursorType)) == NULL)
+	if ((cursor = PyObject_New(PLyCursorObject, PLy_CursorType)) == NULL)
 		return NULL;
+#if PY_VERSION_HEX < 0x03080000
+	/* Workaround for Python issue 35810; no longer necessary in Python 3.8 */
+	Py_INCREF(PLy_CursorType);
+#endif
 	cursor->portalname = NULL;
 	cursor->closed = false;
 	cursor->mcxt = AllocSetContextCreate(TopMemoryContext,
@@ -177,8 +202,12 @@ PLy_cursor_plan(PyObject *ob, PyObject *args)
 		return NULL;
 	}
 
-	if ((cursor = PyObject_New(PLyCursorObject, &PLy_CursorType)) == NULL)
+	if ((cursor = PyObject_New(PLyCursorObject, PLy_CursorType)) == NULL)
 		return NULL;
+#if PY_VERSION_HEX < 0x03080000
+	/* Workaround for Python issue 35810; no longer necessary in Python 3.8 */
+	Py_INCREF(PLy_CursorType);
+#endif
 	cursor->portalname = NULL;
 	cursor->closed = false;
 	cursor->mcxt = AllocSetContextCreate(TopMemoryContext,
@@ -272,30 +301,35 @@ PLy_cursor_plan(PyObject *ob, PyObject *args)
 }
 
 static void
-PLy_cursor_dealloc(PyObject *arg)
+PLy_cursor_dealloc(PLyCursorObject *self)
 {
-	PLyCursorObject *cursor;
+#if PY_VERSION_HEX >= 0x03080000
+	PyTypeObject *tp = Py_TYPE(self);
+#endif
 	Portal		portal;
 
-	cursor = (PLyCursorObject *) arg;
-
-	if (!cursor->closed)
+	if (!self->closed)
 	{
-		portal = GetPortalByName(cursor->portalname);
+		portal = GetPortalByName(self->portalname);
 
 		if (PortalIsValid(portal))
 		{
 			UnpinPortal(portal);
 			SPI_cursor_close(portal);
 		}
-		cursor->closed = true;
+		self->closed = true;
 	}
-	if (cursor->mcxt)
+	if (self->mcxt)
 	{
-		MemoryContextDelete(cursor->mcxt);
-		cursor->mcxt = NULL;
+		MemoryContextDelete(self->mcxt);
+		self->mcxt = NULL;
 	}
-	arg->ob_type->tp_free(arg);
+
+	PyObject_Free(self);
+#if PY_VERSION_HEX >= 0x03080000
+	/* This was not needed before Python 3.8 (Python issue 35810) */
+	Py_DECREF(tp);
+#endif
 }
 
 static PyObject *
diff --git a/src/pl/plpython/plpy_planobject.c b/src/pl/plpython/plpy_planobject.c
index 9427674d2f4..3e385555e5e 100644
--- a/src/pl/plpython/plpy_planobject.c
+++ b/src/pl/plpython/plpy_planobject.c
@@ -12,7 +12,7 @@
 #include "plpython.h"
 #include "utils/memutils.h"
 
-static void PLy_plan_dealloc(PyObject *arg);
+static void PLy_plan_dealloc(PLyPlanObject *self);
 static PyObject *PLy_plan_cursor(PyObject *self, PyObject *args);
 static PyObject *PLy_plan_execute(PyObject *self, PyObject *args);
 static PyObject *PLy_plan_status(PyObject *self, PyObject *args);
@@ -26,20 +26,37 @@ static PyMethodDef PLy_plan_methods[] = {
 	{NULL, NULL, 0, NULL}
 };
 
-static PyTypeObject PLy_PlanType = {
-	PyVarObject_HEAD_INIT(NULL, 0)
-	.tp_name = "PLyPlan",
-	.tp_basicsize = sizeof(PLyPlanObject),
-	.tp_dealloc = PLy_plan_dealloc,
-	.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
-	.tp_doc = PLy_plan_doc,
-	.tp_methods = PLy_plan_methods,
+static PyType_Slot PLyPlan_slots[] =
+{
+	{
+		Py_tp_dealloc, PLy_plan_dealloc
+	},
+	{
+		Py_tp_doc, (char *) PLy_plan_doc
+	},
+	{
+		Py_tp_methods, PLy_plan_methods
+	},
+	{
+		0, NULL
+	}
 };
 
+static PyType_Spec PLyPlan_spec =
+{
+	.name = "PLyPlan",
+		.basicsize = sizeof(PLyPlanObject),
+		.flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
+		.slots = PLyPlan_slots,
+};
+
+static PyTypeObject *PLy_PlanType;
+
 void
 PLy_plan_init_type(void)
 {
-	if (PyType_Ready(&PLy_PlanType) < 0)
+	PLy_PlanType = (PyTypeObject *) PyType_FromSpec(&PLyPlan_spec);
+	if (!PLy_PlanType)
 		elog(ERROR, "could not initialize PLy_PlanType");
 }
 
@@ -48,8 +65,12 @@ PLy_plan_new(void)
 {
 	PLyPlanObject *ob;
 
-	if ((ob = PyObject_New(PLyPlanObject, &PLy_PlanType)) == NULL)
+	if ((ob = PyObject_New(PLyPlanObject, PLy_PlanType)) == NULL)
 		return NULL;
+#if PY_VERSION_HEX < 0x03080000
+	/* Workaround for Python issue 35810; no longer necessary in Python 3.8 */
+	Py_INCREF(PLy_PlanType);
+#endif
 
 	ob->plan = NULL;
 	ob->nargs = 0;
@@ -63,25 +84,32 @@ PLy_plan_new(void)
 bool
 is_PLyPlanObject(PyObject *ob)
 {
-	return ob->ob_type == &PLy_PlanType;
+	return ob->ob_type == PLy_PlanType;
 }
 
 static void
-PLy_plan_dealloc(PyObject *arg)
+PLy_plan_dealloc(PLyPlanObject *self)
 {
-	PLyPlanObject *ob = (PLyPlanObject *) arg;
+#if PY_VERSION_HEX >= 0x03080000
+	PyTypeObject *tp = Py_TYPE(self);
+#endif
 
-	if (ob->plan)
+	if (self->plan)
 	{
-		SPI_freeplan(ob->plan);
-		ob->plan = NULL;
+		SPI_freeplan(self->plan);
+		self->plan = NULL;
 	}
-	if (ob->mcxt)
+	if (self->mcxt)
 	{
-		MemoryContextDelete(ob->mcxt);
-		ob->mcxt = NULL;
+		MemoryContextDelete(self->mcxt);
+		self->mcxt = NULL;
 	}
-	arg->ob_type->tp_free(arg);
+
+	PyObject_Free(self);
+#if PY_VERSION_HEX >= 0x03080000
+	/* This was not needed before Python 3.8 (Python issue 35810) */
+	Py_DECREF(tp);
+#endif
 }
 
 
diff --git a/src/pl/plpython/plpy_procedure.c b/src/pl/plpython/plpy_procedure.c
index c35a3b801ab..b494eeb474f 100644
--- a/src/pl/plpython/plpy_procedure.c
+++ b/src/pl/plpython/plpy_procedure.c
@@ -350,6 +350,7 @@ PLy_procedure_compile(PLyProcedure *proc, const char *src)
 {
 	PyObject   *crv = NULL;
 	char	   *msrc;
+	PyObject   *code0;
 
 	proc->globals = PyDict_Copy(PLy_interp_globals);
 
@@ -368,7 +369,9 @@ PLy_procedure_compile(PLyProcedure *proc, const char *src)
 	msrc = PLy_procedure_munge_source(proc->pyname, src);
 	/* Save the mangled source for later inclusion in tracebacks */
 	proc->src = MemoryContextStrdup(proc->mcxt, msrc);
-	crv = PyRun_String(msrc, Py_file_input, proc->globals, NULL);
+	code0 = Py_CompileString(msrc, "<string>", Py_file_input);
+	if (code0)
+		crv = PyEval_EvalCode(code0, proc->globals, NULL);
 	pfree(msrc);
 
 	if (crv != NULL)
diff --git a/src/pl/plpython/plpy_resultobject.c b/src/pl/plpython/plpy_resultobject.c
index 95acce65493..80fa1d7accc 100644
--- a/src/pl/plpython/plpy_resultobject.c
+++ b/src/pl/plpython/plpy_resultobject.c
@@ -10,7 +10,7 @@
 #include "plpy_resultobject.h"
 #include "plpython.h"
 
-static void PLy_result_dealloc(PyObject *arg);
+static void PLy_result_dealloc(PLyResultObject *self);
 static PyObject *PLy_result_colnames(PyObject *self, PyObject *unused);
 static PyObject *PLy_result_coltypes(PyObject *self, PyObject *unused);
 static PyObject *PLy_result_coltypmods(PyObject *self, PyObject *unused);
@@ -24,17 +24,6 @@ static int	PLy_result_ass_subscript(PyObject *arg, PyObject *item, PyObject *val
 
 static char PLy_result_doc[] = "Results of a PostgreSQL query";
 
-static PySequenceMethods PLy_result_as_sequence = {
-	.sq_length = PLy_result_length,
-	.sq_item = PLy_result_item,
-};
-
-static PyMappingMethods PLy_result_as_mapping = {
-	.mp_length = PLy_result_length,
-	.mp_subscript = PLy_result_subscript,
-	.mp_ass_subscript = PLy_result_ass_subscript,
-};
-
 static PyMethodDef PLy_result_methods[] = {
 	{"colnames", PLy_result_colnames, METH_NOARGS, NULL},
 	{"coltypes", PLy_result_coltypes, METH_NOARGS, NULL},
@@ -44,23 +33,55 @@ static PyMethodDef PLy_result_methods[] = {
 	{NULL, NULL, 0, NULL}
 };
 
-static PyTypeObject PLy_ResultType = {
-	PyVarObject_HEAD_INIT(NULL, 0)
-	.tp_name = "PLyResult",
-	.tp_basicsize = sizeof(PLyResultObject),
-	.tp_dealloc = PLy_result_dealloc,
-	.tp_as_sequence = &PLy_result_as_sequence,
-	.tp_as_mapping = &PLy_result_as_mapping,
-	.tp_str = &PLy_result_str,
-	.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
-	.tp_doc = PLy_result_doc,
-	.tp_methods = PLy_result_methods,
+static PyType_Slot PLyResult_slots[] =
+{
+	{
+		Py_tp_dealloc, PLy_result_dealloc
+	},
+	{
+		Py_sq_length, PLy_result_length
+	},
+	{
+		Py_sq_item, PLy_result_item
+	},
+	{
+		Py_mp_length, PLy_result_length
+	},
+	{
+		Py_mp_subscript, PLy_result_subscript
+	},
+	{
+		Py_mp_ass_subscript, PLy_result_ass_subscript
+	},
+	{
+		Py_tp_str, PLy_result_str
+	},
+	{
+		Py_tp_doc, (char *) PLy_result_doc
+	},
+	{
+		Py_tp_methods, PLy_result_methods
+	},
+	{
+		0, NULL
+	}
+};
+
+static PyType_Spec PLyResult_spec =
+{
+	.name = "PLyResult",
+		.basicsize = sizeof(PLyResultObject),
+		.flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
+		.slots = PLyResult_slots,
 };
 
+static PyTypeObject *PLy_ResultType;
+
 void
 PLy_result_init_type(void)
 {
-	if (PyType_Ready(&PLy_ResultType) < 0)
+	PLy_ResultType = (PyTypeObject *) PyType_FromSpec(&PLyResult_spec);
+	if (!PLy_ResultType)
 		elog(ERROR, "could not initialize PLy_ResultType");
 }
 
@@ -69,8 +90,12 @@ PLy_result_new(void)
 {
 	PLyResultObject *ob;
 
-	if ((ob = PyObject_New(PLyResultObject, &PLy_ResultType)) == NULL)
+	if ((ob = PyObject_New(PLyResultObject, PLy_ResultType)) == NULL)
 		return NULL;
+#if PY_VERSION_HEX < 0x03080000
+	/* Workaround for Python issue 35810; no longer necessary in Python 3.8 */
+	Py_INCREF(PLy_ResultType);
+#endif
 
 	/* ob->tuples = NULL; */
 
@@ -89,20 +114,26 @@ PLy_result_new(void)
 }
 
 static void
-PLy_result_dealloc(PyObject *arg)
+PLy_result_dealloc(PLyResultObject *self)
 {
-	PLyResultObject *ob = (PLyResultObject *) arg;
-
-	Py_XDECREF(ob->nrows);
-	Py_XDECREF(ob->rows);
-	Py_XDECREF(ob->status);
-	if (ob->tupdesc)
+#if PY_VERSION_HEX >= 0x03080000
+	PyTypeObject *tp = Py_TYPE(self);
+#endif
+
+	Py_XDECREF(self->nrows);
+	Py_XDECREF(self->rows);
+	Py_XDECREF(self->status);
+	if (self->tupdesc)
 	{
-		FreeTupleDesc(ob->tupdesc);
-		ob->tupdesc = NULL;
+		FreeTupleDesc(self->tupdesc);
+		self->tupdesc = NULL;
 	}
 
-	arg->ob_type->tp_free(arg);
+	PyObject_Free(self);
+#if PY_VERSION_HEX >= 0x03080000
+	/* This was not needed before Python 3.8 (Python issue 35810) */
+	Py_DECREF(tp);
+#endif
 }
 
 static PyObject *
@@ -125,7 +156,7 @@ PLy_result_colnames(PyObject *self, PyObject *unused)
 	{
 		Form_pg_attribute attr = TupleDescAttr(ob->tupdesc, i);
 
-		PyList_SET_ITEM(list, i, PLyUnicode_FromString(NameStr(attr->attname)));
+		PyList_SetItem(list, i, PLyUnicode_FromString(NameStr(attr->attname)));
 	}
 
 	return list;
@@ -151,7 +182,7 @@ PLy_result_coltypes(PyObject *self, PyObject *unused)
 	{
 		Form_pg_attribute attr = TupleDescAttr(ob->tupdesc, i);
 
-		PyList_SET_ITEM(list, i, PyLong_FromLong(attr->atttypid));
+		PyList_SetItem(list, i, PyLong_FromLong(attr->atttypid));
 	}
 
 	return list;
@@ -177,7 +208,7 @@ PLy_result_coltypmods(PyObject *self, PyObject *unused)
 	{
 		Form_pg_attribute attr = TupleDescAttr(ob->tupdesc, i);
 
-		PyList_SET_ITEM(list, i, PyLong_FromLong(attr->atttypmod));
+		PyList_SetItem(list, i, PyLong_FromLong(attr->atttypmod));
 	}
 
 	return list;
@@ -227,7 +258,7 @@ PLy_result_str(PyObject *arg)
 	PLyResultObject *ob = (PLyResultObject *) arg;
 
 	return PyUnicode_FromFormat("<%s status=%S nrows=%S rows=%S>",
-								Py_TYPE(ob)->tp_name,
+								"PLyResult",
 								ob->status,
 								ob->nrows,
 								ob->rows);
diff --git a/src/pl/plpython/plpy_subxactobject.c b/src/pl/plpython/plpy_subxactobject.c
index 5c92a0e089a..ad24a9fc4b8 100644
--- a/src/pl/plpython/plpy_subxactobject.c
+++ b/src/pl/plpython/plpy_subxactobject.c
@@ -15,7 +15,6 @@
 List	   *explicit_subtransactions = NIL;
 
 
-static void PLy_subtransaction_dealloc(PyObject *subxact);
 static PyObject *PLy_subtransaction_enter(PyObject *self, PyObject *unused);
 static PyObject *PLy_subtransaction_exit(PyObject *self, PyObject *args);
 
@@ -31,21 +30,35 @@ static PyMethodDef PLy_subtransaction_methods[] = {
 	{NULL, NULL, 0, NULL}
 };
 
-static PyTypeObject PLy_SubtransactionType = {
-	PyVarObject_HEAD_INIT(NULL, 0)
-	.tp_name = "PLySubtransaction",
-	.tp_basicsize = sizeof(PLySubtransactionObject),
-	.tp_dealloc = PLy_subtransaction_dealloc,
-	.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
-	.tp_doc = PLy_subtransaction_doc,
-	.tp_methods = PLy_subtransaction_methods,
+static PyType_Slot PLySubtransaction_slots[] =
+{
+	{
+		Py_tp_doc, (char *) PLy_subtransaction_doc
+	},
+	{
+		Py_tp_methods, PLy_subtransaction_methods
+	},
+	{
+		0, NULL
+	}
 };
 
+static PyType_Spec PLySubtransaction_spec =
+{
+	.name = "PLySubtransaction",
+		.basicsize = sizeof(PLySubtransactionObject),
+		.flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
+		.slots = PLySubtransaction_slots,
+};
+
+static PyTypeObject *PLy_SubtransactionType;
+
 
 void
 PLy_subtransaction_init_type(void)
 {
-	if (PyType_Ready(&PLy_SubtransactionType) < 0)
+	PLy_SubtransactionType = (PyTypeObject *) PyType_FromSpec(&PLySubtransaction_spec);
+	if (!PLy_SubtransactionType)
 		elog(ERROR, "could not initialize PLy_SubtransactionType");
 }
 
@@ -55,10 +68,13 @@ PLy_subtransaction_new(PyObject *self, PyObject *unused)
 {
 	PLySubtransactionObject *ob;
 
-	ob = PyObject_New(PLySubtransactionObject, &PLy_SubtransactionType);
-
+	ob = PyObject_New(PLySubtransactionObject, PLy_SubtransactionType);
 	if (ob == NULL)
 		return NULL;
+#if PY_VERSION_HEX < 0x03080000
+	/* Workaround for Python issue 35810; no longer necessary in Python 3.8 */
+	Py_INCREF(PLy_SubtransactionType);
+#endif
 
 	ob->started = false;
 	ob->exited = false;
@@ -66,12 +82,6 @@ PLy_subtransaction_new(PyObject *self, PyObject *unused)
 	return (PyObject *) ob;
 }
 
-/* Python requires a dealloc function to be defined */
-static void
-PLy_subtransaction_dealloc(PyObject *subxact)
-{
-}
-
 /*
  * subxact.__enter__() or subxact.enter()
  *
diff --git a/src/pl/plpython/plpy_typeio.c b/src/pl/plpython/plpy_typeio.c
index 51e1d610259..1d127ae3ffe 100644
--- a/src/pl/plpython/plpy_typeio.c
+++ b/src/pl/plpython/plpy_typeio.c
@@ -723,7 +723,7 @@ PLyList_FromArray_recurse(PLyDatumToOb *elm, int *dims, int ndim, int dim,
 
 			sublist = PLyList_FromArray_recurse(elm, dims, ndim, dim + 1,
 												dataptr_p, bitmap_p, bitmask_p);
-			PyList_SET_ITEM(list, i, sublist);
+			PyList_SetItem(list, i, sublist);
 		}
 	}
 	else
@@ -742,14 +742,14 @@ PLyList_FromArray_recurse(PLyDatumToOb *elm, int *dims, int ndim, int dim,
 			if (bitmap && (*bitmap & bitmask) == 0)
 			{
 				Py_INCREF(Py_None);
-				PyList_SET_ITEM(list, i, Py_None);
+				PyList_SetItem(list, i, Py_None);
 			}
 			else
 			{
 				Datum		itemvalue;
 
 				itemvalue = fetch_att(dataptr, elm->typbyval, elm->typlen);
-				PyList_SET_ITEM(list, i, elm->func(elm, itemvalue));
+				PyList_SetItem(list, i, elm->func(elm, itemvalue));
 				dataptr = att_addlength_pointer(dataptr, elm->typlen, dataptr);
 				dataptr = (char *) att_align_nominal(dataptr, elm->typalign);
 			}

base-commit: ad40644eb8582fc1f537330b76ae7893cacf7b21
-- 
2.48.1

From dd07e62e041dfae67c1182226b772fe59a71f78e Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Wed, 5 Mar 2025 17:38:06 +0100
Subject: [PATCH v3 2/2] Activate Python "Limited API" in PL/Python

This allows building PL/Python against any Python 3.x version and
using another Python 3.x version at run time.

Discussion: https://www.postgresql.org/message-id/flat/ee410de1-1e0b-4770-b125-eeefd4726a24@eisentraut.org
---
 src/pl/plpython/plpython.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/pl/plpython/plpython.h b/src/pl/plpython/plpython.h
index ec822577260..06fc1a5440f 100644
--- a/src/pl/plpython/plpython.h
+++ b/src/pl/plpython/plpython.h
@@ -19,6 +19,15 @@
 #error Python.h must be included via plpython.h
 #endif
 
+/*
+ * Enable Python Limited API
+ *
+ * XXX currently not enabled on MSVC because of build failures
+ */
+#if !defined(_MSC_VER)
+#define Py_LIMITED_API 0x03020000
+#endif
+
 /*
  * Pull in Python headers via a wrapper header, to control the scope of
  * the system_header pragma therein.
-- 
2.48.1

From 52efe8af1377e8adbac3533537f15ad20f7af1cf Mon Sep 17 00:00:00 2001
From: Bryan Green <dbryan.green@gmail.com>
Date: Fri, 2 Jan 2026 10:48:54 -0600
Subject: [PATCH v1] Enable Python Limited API for PL/Python on MSVC

Previously, the Python Limited API was disabled on MSVC due to build
failures caused by Meson not knowing to link against python3.lib
instead of python3XX.lib when using the Limited API.

This commit works around the Meson limitation by explicitly finding
and linking against python3.lib on MSVC, and removes the preprocessor
guard that was disabling the Limited API on MSVC in plpython.h.

This requires python3.lib to be present in the Python installation,
which is included when Python is installed.

Discussion: https://www.postgresql.org/message-id/flat/ee410de1-1e0b-4770-b125-eeefd4726a24%40eisentraut.org
---
 meson.build                | 12 +++++++++++-
 src/pl/plpython/plpython.h |  4 ----
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/meson.build b/meson.build
index d7c5193d4c..e4ecd78a7a 100644
--- a/meson.build
+++ b/meson.build
@@ -1329,7 +1329,17 @@ if not pyopt.disabled()
   pm = import('python')
   python3_inst = pm.find_installation(python.full_path(), required: pyopt)
   if python3_inst.found()
-    python3_dep = python3_inst.dependency(embed: true, required: pyopt)
+    # For Limited API on MSVC, link against python3.lib instead of python3XX.lib
+    if host_system == 'windows' and cc.get_id() == 'msvc'
+      python3_libdir = python3_inst.get_variable('prefix') / 'libs'
+      python3_lib = cc.find_library('python3', dirs: python3_libdir, required: pyopt)
+      python3_dep = declare_dependency(
+        include_directories: include_directories(python3_inst.get_variable('prefix') / 'include'),
+        dependencies: python3_lib,
+      )
+    else
+      python3_dep = python3_inst.dependency(embed: true, required: pyopt)
+    endif
     # Remove this check after we depend on Meson >= 1.1.0
     if not cc.check_header('Python.h', dependencies: python3_dep, required: pyopt, include_directories: postgres_inc)
       python3_dep = not_found_dep
diff --git a/src/pl/plpython/plpython.h b/src/pl/plpython/plpython.h
index 118b310084..445f7bc31a 100644
--- a/src/pl/plpython/plpython.h
+++ b/src/pl/plpython/plpython.h
@@ -25,12 +25,8 @@
 
 /*
  * Enable Python Limited API
- *
- * XXX currently not enabled on MSVC because of build failures
  */
-#if !defined(_MSC_VER)
 #define Py_LIMITED_API 0x03020000
-#endif
 
 /*
  * Pull in Python headers via a wrapper header, to control the scope of
-- 
2.52.0.windows.1