Add private APIs to get Python version before bootstrapping Python (#3625)

Use them in Module.preRun to initialize the filesystem.

Makefile

@@ -85,7 +85,8 @@ dist/libpyodide.a: \
 	src/core/pyproxy.o \
 	src/core/python2js_buffer.o \
 	src/core/python2js.o \
-	src/core/pyodide_pre.o
+	src/core/pyodide_pre.o \
+	src/core/pyversion.o
 	emar rcs dist/libpyodide.a $(filter %.o,$^)
 
 

src/core/pyversion.c

@@ -0,0 +1,21 @@
+#define PY_SSIZE_T_CLEAN
+#include "Python.h"
+#include <emscripten.h>
+
+EMSCRIPTEN_KEEPALIVE int
+py_version_major()
+{
+  return PY_MAJOR_VERSION;
+}
+
+EMSCRIPTEN_KEEPALIVE int
+py_version_minor()
+{
+  return PY_MINOR_VERSION;
+}
+
+EMSCRIPTEN_KEEPALIVE int
+py_version_micro()
+{
+  return PY_MICRO_VERSION;
+}

src/core/pyversion.h

@@ -0,0 +1,13 @@
+#ifndef PYVERSION_H
+#define PYVERSION_H
+
+int
+py_version_major();
+
+int
+py_version_minor();
+
+int
+py_version_micro();
+
+#endif /* PYVERSION_H */

src/js/module.ts

@@ -130,19 +130,22 @@ function mountLocalDirectories(Module: Module, mounts: string[]) {
  * @param stdlibPromise A promise that resolves to the standard library.
  */
 function installStdlib(Module: Module, stdlibURL: string) {
-  // TODO(ryanking13): Get python version from Python.h
-
   const stdlibPromise: Promise<Uint8Array> = loadBinaryFile(stdlibURL);
 
   Module.preRun.push(() => {
+    /* @ts-ignore */
+    const pymajor = Module._py_version_major();
+    /* @ts-ignore */
+    const pyminor = Module._py_version_minor();
+
     Module.FS.mkdirTree("/lib");
-    Module.FS.mkdirTree("/lib/python3.11/site-packages");
+    Module.FS.mkdirTree(`/lib/python${pymajor}.${pyminor}/site-packages`);
 
     Module.addRunDependency("install-stdlib");
 
     stdlibPromise
       .then((stdlib: Uint8Array) => {
-        Module.FS.writeFile("/lib/python311.zip", stdlib);
+        Module.FS.writeFile(`/lib/python${pymajor}${pyminor}.zip`, stdlib);
       })
       .catch((e) => {
         console.error("Error occurred while installing the standard library:");

src/tests/test_pyodide.py

@@ -1782,3 +1782,15 @@ def test_python_error(selenium):
     )
     assert msg.endswith("TypeError: oops\n")
     assert ty == "TypeError"
+
+
+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());
+        sys.destroy();
+        """
+    )