Use _Py_Version to compute Python version for library setup

This requires this upstream fix which came out in Emscripten 3.1.73:
emscripten-core/emscripten#23020

Applied upstream in the cpython repo here:
https://github.com/python/cpython/pull/127113/files#diff-31f61a127a59386957acba86e9acedf0a96bc6ebe1ac159a48e39b1a291111b5R73-R75

This fixes an error that occurs when building with assertions -- we
called `_py_version_major` before the runtime was set up so it triggered
an assertion failure.

Author: hoodmane

Makefile

@@ -97,7 +97,6 @@ src/core/libpyodide.a: \
 	src/core/jslib_asm.o \
 	src/core/python2js.o \
 	src/core/pyodide_pre.o \
-	src/core/pyversion.o \
 	src/core/stack_switching/pystate.o \
 	src/core/stack_switching/suspenders.o
 	emar rcs src/core/libpyodide.a $(filter %.o,$^)

Makefile.envs

@@ -234,6 +234,7 @@ EXPORTS=_main \
    ,__PyTraceback_Add \
    ,_PyUnicode_Data \
    ,_PyUnicode_New \
+   ,_Py_Version \
 
 
 ifeq ($(DISABLE_DYLINK), 1)

src/core/_pyodide_core.c

@@ -46,14 +46,11 @@ static struct PyModuleDef core_module_def = {
 
 void
 pyodide_export(void);
-int
-py_version_major(void);
 void
 set_new_cframe(void* frame);
-// Force _pyodide_core.o, _pyodide_pre.gen.o, and pystate.o to be included by
+// Force _pyodide_pre.gen.o, and pystate.o to be included by
 // using a symbol from each of them.
 void* pyodide_export_ = pyodide_export;
-void* py_version_major_ = py_version_major;
 void* set_new_cframe_ = set_new_cframe;
 
 // clang-format off

src/core/pyversion.c

@@ -3,7 +3,7 @@
 import { ConfigType } from "./pyodide";
 import { initializeNativeFS } from "./nativefs";
 import { loadBinaryFile, getBinaryResponse } from "./compat";
-import { API, PreRunFunc } from "./types";
+import { API, PreRunFunc, type Module } from "./types";
 
 /**
  * @private
@@ -110,6 +110,15 @@ function mountLocalDirectories(mounts: string[]): PreRunFunc {
   };
 }
 
+function computeVersionTuple(Module: Module): [number, number, number] {
+  const versionHex = Module.HEAPU32[Module._Py_Version / 4].toString(16);
+  const res = versionHex
+    .padStart(8, "0")
+    .match(/.{1,2}/g)!
+    .map((x) => parseInt(x, 16));
+  return res as any;
+}
+
 /**
  * Install the Python standard library to the virtual file system.
  *
@@ -125,12 +134,9 @@ function mountLocalDirectories(mounts: string[]): PreRunFunc {
  */
 function installStdlib(stdlibURL: string): PreRunFunc {
   const stdlibPromise: Promise<Uint8Array> = loadBinaryFile(stdlibURL);
-  return (Module) => {
-    /* @ts-ignore */
-    const pymajor = Module._py_version_major();
-    /* @ts-ignore */
-    const pyminor = Module._py_version_minor();
-
+  return (Module: Module) => {
+    Module.API.pyVersionTuple = computeVersionTuple(Module);
+    const [pymajor, pyminor] = Module.API.pyVersionTuple;
     Module.FS.mkdirTree("/lib");
     Module.FS.mkdirTree(`/lib/python${pymajor}.${pyminor}/site-packages`);
 

src/core/pyversion.h

@@ -340,6 +340,7 @@ export interface Module {
   _Py_EMSCRIPTEN_SIGNAL_HANDLING: number;
   Py_EmscriptenSignalBuffer: TypedArray;
   HEAP8: Uint8Array;
+  HEAPU32: Uint32Array;
   __hiwire_get(a: number): any;
   __hiwire_set(a: number, b: any): void;
   __hiwire_immortal_add(a: any): void;
@@ -350,6 +351,7 @@ export interface Module {
   handle_js_error(e: any): void;
   exitCode: number | undefined;
   ExitStatus: { new (exitCode: number): Error };
+  _Py_Version: number;
 }
 
 type LockfileInfo = {
@@ -510,7 +512,7 @@ export interface API {
   syncUpSnapshotLoad3(conf: SnapshotConfig): void;
   abortSignalAny: (signals: AbortSignal[]) => AbortSignal;
   version: string;
-
+  pyVersionTuple: [number, number, number];
   LiteralMap: any;
 }
 

src/js/emscripten-settings.ts

@@ -1770,9 +1770,10 @@ def test_python_version(selenium):
     selenium.run_js(
         """
         sys = pyodide.pyimport("sys");
-        assert(() => sys.version_info.major === pyodide._module._py_version_major());
-        assert(() => sys.version_info.minor === pyodide._module._py_version_minor());
-        assert(() => sys.version_info.micro === pyodide._module._py_version_micro());
+        const [major, minor, micro] = pyodide._api.pyVersionTuple;
+        assert(() => sys.version_info.major === major);
+        assert(() => sys.version_info.minor === minor);
+        assert(() => sys.version_info.micro === micro);
         sys.destroy();
         """
     )