Subinterpretor compatible __res module (2nd attempt)

Cython is not yet subinterpreter compatible. There are no ETA when cython is going to support subinterpreters.

This PR removes cython from hermetic python imoprt hooks in order to make them subinterpretr-compatible.
commit_hash:427b6f9db6afa6695659ee147621e1ccb391d3cb

1 files changed, 82 insertions, 0 deletions

diff --git a/library/python/runtime_py3/test/subinterpreter/py3_subinterpreters.cpp b/library/python/runtime_py3/test/subinterpreter/py3_subinterpreters.cpp
new file mode 100644
index 00000000000..0a934d4db50
--- /dev/null
+++ b/library/python/runtime_py3/test/subinterpreter/py3_subinterpreters.cpp
@@ -0,0 +1,82 @@
+#include "stdout_interceptor.h"
+
+#include <util/stream/str.h>
+
+#include <library/cpp/testing/gtest/gtest.h>
+
+#include <Python.h>
+
+#include <thread>
+#include <algorithm>
+
+struct TSubinterpreters: ::testing::Test {
+    static void SetUpTestSuite() {
+        Py_InitializeEx(0);
+        EXPECT_TRUE(TPyStdoutInterceptor::SetupInterceptionSupport());
+    }
+    static void TearDownTestSuite() {
+        Py_Finalize();
+    }
+
+    static void ThreadPyRun(PyInterpreterState* interp, IOutputStream& pyout, const char* pycode) {
+        PyThreadState* state = PyThreadState_New(interp);
+        PyEval_RestoreThread(state);
+
+        {
+            TPyStdoutInterceptor interceptor{pyout};
+            PyRun_SimpleString(pycode);
+        }
+
+        PyThreadState_Clear(state);
+        PyThreadState_DeleteCurrent();
+    }
+};
+
+TEST_F(TSubinterpreters, NonSubinterpreterFlowStillWorks) {
+    TStringStream pyout;
+    TPyStdoutInterceptor interceptor{pyout};
+
+    PyRun_SimpleString("print('Hello World')");
+    EXPECT_EQ(pyout.Str(), "Hello World\n");
+}
+
+TEST_F(TSubinterpreters, ThreadedSubinterpretersFlowWorks) {
+    TStringStream pyout[2];
+
+    PyInterpreterConfig cfg = {
+        .use_main_obmalloc = 0,
+        .allow_fork = 0,
+        .allow_exec = 0,
+        .allow_threads = 1,
+        .allow_daemon_threads = 0,
+        .check_multi_interp_extensions = 1,
+        .gil = PyInterpreterConfig_OWN_GIL,
+    };
+
+    PyThreadState* mainState = PyThreadState_Get();
+    PyThreadState *sub[2] = {nullptr, nullptr};
+    Py_NewInterpreterFromConfig(&sub[0], &cfg);
+    ASSERT_NE(sub[0], nullptr);
+    Py_NewInterpreterFromConfig(&sub[1], &cfg);
+    ASSERT_NE(sub[1], nullptr);
+    PyThreadState_Swap(mainState);
+
+    PyThreadState* savedState = PyEval_SaveThread();
+    std::array<std::thread, 2> threads{
+        std::thread{ThreadPyRun, sub[0]->interp, std::ref(pyout[0]), "print('Hello Thread 0')"},
+        std::thread{ThreadPyRun, sub[1]->interp, std::ref(pyout[1]), "print('Hello Thread 1')"}
+    };
+    std::ranges::for_each(threads, &std::thread::join);
+    PyEval_RestoreThread(savedState);
+
+    PyThreadState_Swap(sub[0]);
+    Py_EndInterpreter(sub[0]);
+
+    PyThreadState_Swap(sub[1]);
+    Py_EndInterpreter(sub[1]);
+
+    PyThreadState_Swap(mainState);
+
+    EXPECT_EQ(pyout[0].Str(), "Hello Thread 0\n");
+    EXPECT_EQ(pyout[1].Str(), "Hello Thread 1\n");
+}