Python 3.9 support

.github/workflows/test.yml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python: ['3.10', '3.11', '3.12']
+        python: ['3.9', '3.10', '3.11', '3.12']
     steps:
     - uses: actions/checkout@v4
     - name: Set up Python ${{ matrix.python }}

pyproject.toml

@@ -7,7 +7,7 @@ name = "dispatch-py"
 description = "Develop reliable distributed systems on the Dispatch platform."
 readme = "README.md"
 dynamic = ["version"]
-requires-python = ">= 3.10"
+requires-python = ">= 3.9"
 dependencies = [
     "grpcio >= 1.60.0",
     "protobuf >= 4.24.0",
@@ -17,7 +17,8 @@ dependencies = [
     "tblib >= 3.0.0",
     "docopt >= 0.6.2",
     "types-docopt >= 0.6.11.4",
-    "httpx >= 0.27.0"
+    "httpx >= 0.27.0",
+    "typing_extensions >= 4.10"
 ]
 
 [project.optional-dependencies]

src/dispatch/coroutine.py

@@ -48,17 +48,17 @@ def race(*awaitables: Awaitable[Any]) -> list[Any]:  # type: ignore[misc]
     return (yield RaceDirective(awaitables))
 
 
-@dataclass(slots=True)
+@dataclass
 class AllDirective:
     awaitables: tuple[Awaitable[Any], ...]
 
 
-@dataclass(slots=True)
+@dataclass
 class AnyDirective:
     awaitables: tuple[Awaitable[Any], ...]
 
 
-@dataclass(slots=True)
+@dataclass
 class RaceDirective:
     awaitables: tuple[Awaitable[Any], ...]
 

src/dispatch/experimental/durable/frame.c

@@ -6,19 +6,21 @@
 #define PY_SSIZE_T_CLEAN
 #include <Python.h>
 
-#if PY_MAJOR_VERSION != 3 || (PY_MINOR_VERSION < 10 || PY_MINOR_VERSION > 13)
-# error Python 3.10-3.13 is required
+#if PY_MAJOR_VERSION != 3 || (PY_MINOR_VERSION < 9 || PY_MINOR_VERSION > 13)
+# error Python 3.9-3.13 is required
 #endif
 
-// This is a redefinition of the private PyTryBlock from 3.10.
+// This is a redefinition of the private PyTryBlock from <= 3.10.
+// https://github.com/python/cpython/blob/3.9/Include/cpython/frameobject.h#L11
 // https://github.com/python/cpython/blob/3.10/Include/cpython/frameobject.h#L22
 typedef struct {
     int b_type;
     int b_handler;
     int b_level;
 } PyTryBlock;
 
-// This is a redefinition of the private PyCoroWrapper from 3.10-3.13.
+// This is a redefinition of the private PyCoroWrapper from 3.9-3.13.
+// https://github.com/python/cpython/blob/3.9/Objects/genobject.c#L830
 // https://github.com/python/cpython/blob/3.10/Objects/genobject.c#L884
 // https://github.com/python/cpython/blob/3.11/Objects/genobject.c#L1016
 // https://github.com/python/cpython/blob/3.12/Objects/genobject.c#L1003
@@ -51,7 +53,9 @@ static int get_frame_iblock(Frame *frame);
 static void set_frame_iblock(Frame *frame, int iblock);
 static PyTryBlock *get_frame_blockstack(Frame *frame);
 
-#if PY_MINOR_VERSION == 10
+#if PY_MINOR_VERSION == 9
+#include "frame309.h"
+#elif PY_MINOR_VERSION == 10
 #include "frame310.h"
 #elif PY_MINOR_VERSION == 11
 #include "frame311.h"
@@ -78,7 +82,7 @@ static const char *get_type_name(PyObject *obj) {
 
 static PyGenObject *get_generator_like_object(PyObject *obj) {
     if (PyGen_Check(obj) || PyCoro_CheckExact(obj) || PyAsyncGen_CheckExact(obj)) {
-        // Note: In Python 3.10-3.13, the PyGenObject, PyCoroObject and PyAsyncGenObject
+        // Note: In Python 3.9-3.13, the PyGenObject, PyCoroObject and PyAsyncGenObject
         // have the same layout, they just have different field prefixes (gi_, cr_, ag_).
         // We cast to PyGenObject here so that the remainder of the code can use the gi_
         // prefix for all three cases.
@@ -386,7 +390,7 @@ static PyObject *ext_set_frame_stack_at(PyObject *self, PyObject *args) {
     }
     PyObject **localsplus = get_frame_localsplus(frame);
     PyObject *prev = localsplus[index];
-    if (Py_IsTrue(unset)) {
+    if (PyObject_IsTrue(unset)) {
         localsplus[index] = NULL;
     } else {
         Py_INCREF(stack_obj);

src/dispatch/experimental/durable/frame.pyi

@@ -1,55 +1,61 @@
 from types import FrameType
-from typing import Any, AsyncGenerator, Coroutine, Generator, Tuple
+from typing import Any, AsyncGenerator, Coroutine, Generator, Tuple, Union
 
-def get_frame_ip(frame: FrameType | Coroutine | Generator | AsyncGenerator) -> int:
+def get_frame_ip(frame: Union[FrameType, Coroutine, Generator, AsyncGenerator]) -> int:
     """Get instruction pointer of a generator or coroutine."""
 
-def set_frame_ip(frame: FrameType | Coroutine | Generator | AsyncGenerator, ip: int):
+def set_frame_ip(
+    frame: Union[FrameType, Coroutine, Generator, AsyncGenerator], ip: int
+):
     """Set instruction pointer of a generator or coroutine."""
 
-def get_frame_sp(frame: FrameType | Coroutine | Generator | AsyncGenerator) -> int:
+def get_frame_sp(frame: Union[FrameType, Coroutine, Generator, AsyncGenerator]) -> int:
     """Get stack pointer of a generator or coroutine."""
 
-def set_frame_sp(frame: FrameType | Coroutine | Generator | AsyncGenerator, sp: int):
+def set_frame_sp(
+    frame: Union[FrameType, Coroutine, Generator, AsyncGenerator], sp: int
+):
     """Set stack pointer of a generator or coroutine."""
 
-def get_frame_bp(frame: FrameType | Coroutine | Generator | AsyncGenerator) -> int:
+def get_frame_bp(frame: Union[FrameType, Coroutine, Generator, AsyncGenerator]) -> int:
     """Get block pointer of a generator or coroutine."""
 
-def set_frame_bp(frame: FrameType | Coroutine | Generator | AsyncGenerator, bp: int):
+def set_frame_bp(
+    frame: Union[FrameType, Coroutine, Generator, AsyncGenerator], bp: int
+):
     """Set block pointer of a generator or coroutine."""
 
 def get_frame_stack_at(
-    frame: FrameType | Coroutine | Generator | AsyncGenerator, index: int
+    frame: Union[FrameType, Coroutine, Generator, AsyncGenerator], index: int
 ) -> Tuple[bool, Any]:
     """Get an object from a generator or coroutine's stack, as an (is_null, obj) tuple."""
 
 def set_frame_stack_at(
-    frame: FrameType | Coroutine | Generator | AsyncGenerator,
+    frame: Union[FrameType, Coroutine, Generator, AsyncGenerator],
     index: int,
     unset: bool,
     value: Any,
 ):
     """Set or unset an object on the stack of a generator or coroutine."""
 
 def get_frame_block_at(
-    frame: FrameType | Coroutine | Generator | AsyncGenerator, index: int
+    frame: Union[FrameType, Coroutine, Generator, AsyncGenerator], index: int
 ) -> Tuple[int, int, int]:
     """Get a block from a generator or coroutine."""
 
 def set_frame_block_at(
-    frame: FrameType | Coroutine | Generator | AsyncGenerator,
+    frame: Union[FrameType, Coroutine, Generator, AsyncGenerator],
     index: int,
     value: Tuple[int, int, int],
 ):
     """Restore a block of a generator or coroutine."""
 
 def get_frame_state(
-    frame: FrameType | Coroutine | Generator | AsyncGenerator,
+    frame: Union[FrameType, Coroutine, Generator, AsyncGenerator],
 ) -> int:
     """Get frame state of a generator or coroutine."""
 
 def set_frame_state(
-    frame: FrameType | Coroutine | Generator | AsyncGenerator, state: int
+    frame: Union[FrameType, Coroutine, Generator, AsyncGenerator], state: int
 ):
     """Set frame state of a generator or coroutine."""

src/dispatch/experimental/durable/frame309.h

@@ -0,0 +1,144 @@
+// This is a redefinition of the private/opaque frame object.
+// https://github.com/python/cpython/blob/3.9/Include/cpython/frameobject.h#L17
+//
+// In Python <= 3.10, `struct _frame` is both the PyFrameObject and
+// PyInterpreterFrame. From Python 3.11 onwards, the two were split with the
+// PyFrameObject (struct _frame) pointing to struct _PyInterpreterFrame.
+struct Frame {
+    PyObject_VAR_HEAD
+    struct Frame *f_back; // struct _frame
+    PyCodeObject *f_code;
+    PyObject *f_builtins;
+    PyObject *f_globals;
+    PyObject *f_locals;
+    PyObject **f_valuestack;
+    PyObject **f_stacktop;
+    PyObject *f_trace;
+    char f_trace_lines;
+    char f_trace_opcodes;
+    PyObject *f_gen;
+    int f_lasti;
+    int f_lineno;
+    int f_iblock;
+    char f_executing;
+    PyTryBlock f_blockstack[CO_MAXBLOCKS];
+    PyObject *f_localsplus[1];
+};
+
+// Python 3.9 and prior didn't have an explicit enum of frame states,
+// but we can derive them based on the presence of a frame, and other
+// information found on the frame, for compatibility with later versions.
+typedef enum _framestate {
+    FRAME_CREATED = -2,
+    FRAME_EXECUTING = 0,
+    FRAME_CLEARED = 4
+} FrameState;
+
+/*
+// This is the definition of PyGenObject for reference to developers
+// working on the extension.
+//
+// Note that PyCoroObject and PyAsyncGenObject have the same layout as
+// PyGenObject, however the struct fields have a cr_ and ag_ prefix
+// (respectively) rather than a gi_ prefix. In Python <= 3.10, PyCoroObject
+// and PyAsyncGenObject have extra fields compared to PyGenObject. In Python
+// 3.11 onwards, the three objects are identical (except for field name
+// prefixes). The extra fields in Python <= 3.10 are not applicable to the
+// extension at this time.
+//
+// https://github.com/python/cpython/blob/3.9/Include/genobject.h#L15
+typedef struct {
+    PyObject_HEAD
+    PyFrameObject *gi_frame;
+    char gi_running;
+    PyObject *gi_code;
+    PyObject *gi_weakreflist;
+    PyObject *gi_name;
+    PyObject *gi_qualname;
+    _PyErr_StackItem gi_exc_state;
+} PyGenObject;
+*/
+
+static Frame *get_frame(PyGenObject *gen_like) {
+    Frame *frame = (Frame *)(gen_like->gi_frame);
+    assert(frame);
+    return frame;
+}
+
+static PyCodeObject *get_frame_code(Frame *frame) {
+    PyCodeObject *code = frame->f_code;
+    assert(code);
+    return code;
+}
+
+static int get_frame_lasti(Frame *frame) {
+    return frame->f_lasti;
+}
+
+static void set_frame_lasti(Frame *frame, int lasti) {
+    frame->f_lasti = lasti;
+}
+
+static int get_frame_state(PyGenObject *gen_like) {
+    // Python 3.9 doesn't have frame states, but we can derive
+    // some for compatibility with later versions and to simplify
+    // the extension.
+    Frame *frame = (Frame *)(gen_like->gi_frame);
+    if (!frame) {
+        return FRAME_CLEARED;
+    }
+    return frame->f_executing ? FRAME_EXECUTING : FRAME_CREATED;
+}
+
+static void set_frame_state(PyGenObject *gen_like, int fs) {
+    Frame *frame = get_frame(gen_like);
+    frame->f_executing = (fs == FRAME_EXECUTING);
+}
+
+static int valid_frame_state(int fs) {
+    return fs == FRAME_CREATED || fs == FRAME_EXECUTING || fs == FRAME_CLEARED;
+}
+
+static int get_frame_stacktop_limit(Frame *frame) {
+    PyCodeObject *code = get_frame_code(frame);
+    return code->co_stacksize + code->co_nlocals;
+}
+
+static int get_frame_stacktop(Frame *frame) {
+    assert(frame->f_localsplus);
+    int stacktop = (int)(frame->f_stacktop - frame->f_localsplus);
+    assert(stacktop >= 0 && stacktop < get_frame_stacktop_limit(frame));
+    return stacktop;
+}
+
+static void set_frame_stacktop(Frame *frame, int stacktop) {
+    assert(stacktop >= 0 && stacktop < get_frame_stacktop_limit(frame));
+    assert(frame->f_localsplus);
+    frame->f_stacktop = frame->f_localsplus + stacktop;
+}
+
+static PyObject **get_frame_localsplus(Frame *frame) {
+    PyObject **localsplus = frame->f_localsplus;
+    assert(localsplus);
+    return localsplus;
+}
+
+static int get_frame_iblock_limit(Frame *frame) {
+    return CO_MAXBLOCKS;
+}
+
+static int get_frame_iblock(Frame *frame) {
+    return frame->f_iblock;
+}
+
+static void set_frame_iblock(Frame *frame, int iblock) {
+    assert(iblock >= 0 && iblock < get_frame_iblock_limit(frame));
+    frame->f_iblock = iblock;
+}
+
+static PyTryBlock *get_frame_blockstack(Frame *frame) {
+    PyTryBlock *blockstack = frame->f_blockstack;
+    assert(blockstack);
+    return blockstack;
+}
+