import pytest import env from pybind11_tests import ConstructorStats from pybind11_tests import modules as m from pybind11_tests.modules import subsubmodule as ms def test_nested_modules(): import pybind11_tests assert pybind11_tests.__name__ == "pybind11_tests" assert pybind11_tests.modules.__name__ == "pybind11_tests.modules" assert ( pybind11_tests.modules.subsubmodule.__name__ == "pybind11_tests.modules.subsubmodule" ) assert m.__name__ == "pybind11_tests.modules" assert ms.__name__ == "pybind11_tests.modules.subsubmodule" assert ms.submodule_func() == "submodule_func()" def test_reference_internal(): b = ms.B() assert str(b.get_a1()) == "A[1]" assert str(b.a1) == "A[1]" assert str(b.get_a2()) == "A[2]" assert str(b.a2) == "A[2]" b.a1 = ms.A(42) b.a2 = ms.A(43) assert str(b.get_a1()) == "A[42]" assert str(b.a1) == "A[42]" assert str(b.get_a2()) == "A[43]" assert str(b.a2) == "A[43]" astats, bstats = ConstructorStats.get(ms.A), ConstructorStats.get(ms.B) assert astats.alive() == 2 assert bstats.alive() == 1 del b assert astats.alive() == 0 assert bstats.alive() == 0 assert astats.values() == ["1", "2", "42", "43"] assert bstats.values() == [] assert astats.default_constructions == 0 assert bstats.default_constructions == 1 assert astats.copy_constructions == 0 assert bstats.copy_constructions == 0 # assert astats.move_constructions >= 0 # Don't invoke any # assert bstats.move_constructions >= 0 # Don't invoke any assert astats.copy_assignments == 2 assert bstats.copy_assignments == 0 assert astats.move_assignments == 0 assert bstats.move_assignments == 0 def test_importing(): from collections import OrderedDict from pybind11_tests.modules import OD assert OD is OrderedDict assert str(OD([(1, "a"), (2, "b")])) == "OrderedDict([(1, 'a'), (2, 'b')])" def test_pydoc(): """Pydoc needs to be able to provide help() for everything inside a pybind11 module""" import pydoc import pybind11_tests assert pybind11_tests.__name__ == "pybind11_tests" assert pybind11_tests.__doc__ == "pybind11 test module" assert pydoc.text.docmodule(pybind11_tests) def test_duplicate_registration(): """Registering two things with the same name""" assert m.duplicate_registration() == [] def test_builtin_key_type(): """Test that all the keys in the builtin modules have type str. Previous versions of pybind11 would add a unicode key in python 2. """ if hasattr(__builtins__, "keys"): keys = __builtins__.keys() else: # this is to make pypy happy since builtins is different there. keys = __builtins__.__dict__.keys() assert {type(k) for k in keys} == {str} @pytest.mark.xfail("env.PYPY", reason="PyModule_GetName()") def test_def_submodule_failures(): sm = m.def_submodule(m, b"ScratchSubModuleName") # Using bytes to show it works. assert sm.__name__ == m.__name__ + "." + "ScratchSubModuleName" malformed_utf8 = b"\x80" if env.PYPY: # It is not worth the effort finding a trigger for a failure when running with PyPy. pytest.skip("Sufficiently exercised on platforms other than PyPy.") else: # Meant to trigger PyModule_GetName() failure: sm_name_orig = sm.__name__ sm.__name__ = malformed_utf8 try: with pytest.raises(Exception): # Seen with Python 3.9: SystemError: nameless module # But we do not want to exercise the internals of PyModule_GetName(), which could # change in future versions of Python, but a bad __name__ is very likely to cause # some kind of failure indefinitely. m.def_submodule(sm, b"SubSubModuleName") finally: # Clean up to ensure nothing gets upset by a module with an invalid __name__. sm.__name__ = sm_name_orig # Purely precautionary. # Meant to trigger PyImport_AddModule() failure: with pytest.raises(UnicodeDecodeError): m.def_submodule(sm, malformed_utf8) ='#n25'>25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 
/*
    tests/test_virtual_functions.cpp -- overriding virtual functions from Python

    Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>

    All rights reserved. Use of this source code is governed by a
    BSD-style license that can be found in the LICENSE file.
*/

#include <pybind11/functional.h>

#include "constructor_stats.h"
#include "pybind11_tests.h"

#include <thread>

/* This is an example class that we'll want to be able to extend from Python */
class ExampleVirt {
public:
    explicit ExampleVirt(int state) : state(state) { print_created(this, state); }
    ExampleVirt(const ExampleVirt &e) : state(e.state) { print_copy_created(this); }
    ExampleVirt(ExampleVirt &&e) noexcept : state(e.state) {
        print_move_created(this);
        e.state = 0;
    }
    virtual ~ExampleVirt() { print_destroyed(this); }

    virtual int run(int value) {
        py::print("Original implementation of "
                  "ExampleVirt::run(state={}, value={}, str1={}, str2={})"_s.format(
                      state, value, get_string1(), *get_string2()));
        return state + value;
    }

    virtual bool run_bool() = 0;
    virtual void pure_virtual() = 0;

    // Returning a reference/pointer to a type converted from python (numbers, strings, etc.) is a
    // bit trickier, because the actual int& or std::string& or whatever only exists temporarily,
    // so we have to handle it specially in the trampoline class (see below).
    virtual const std::string &get_string1() { return str1; }
    virtual const std::string *get_string2() { return &str2; }

private:
    int state;
    const std::string str1{"default1"}, str2{"default2"};
};

/* This is a wrapper class that must be generated */
class PyExampleVirt : public ExampleVirt {
public:
    using ExampleVirt::ExampleVirt; /* Inherit constructors */

    int run(int value) override {
        /* Generate wrapping code that enables native function overloading */
        PYBIND11_OVERRIDE(int,         /* Return type */
                          ExampleVirt, /* Parent class */
                          run,         /* Name of function */
                          value        /* Argument(s) */
        );
    }

    bool run_bool() override {
        PYBIND11_OVERRIDE_PURE(bool,        /* Return type */
                               ExampleVirt, /* Parent class */
                               run_bool,    /* Name of function */
                                            /* This function has no arguments. The trailing comma
                                               in the previous line is needed for some compilers */
        );
    }

    void pure_virtual() override {
        PYBIND11_OVERRIDE_PURE(void,         /* Return type */
                               ExampleVirt,  /* Parent class */
                               pure_virtual, /* Name of function */
                                             /* This function has no arguments. The trailing comma
                                                in the previous line is needed for some compilers */
        );
    }

    // We can return reference types for compatibility with C++ virtual interfaces that do so, but
    // note they have some significant limitations (see the documentation).
    const std::string &get_string1() override {
        PYBIND11_OVERRIDE(const std::string &, /* Return type */
                          ExampleVirt,         /* Parent class */
                          get_string1,         /* Name of function */
                                               /* (no arguments) */
        );
    }

    const std::string *get_string2() override {
        PYBIND11_OVERRIDE(const std::string *, /* Return type */
                          ExampleVirt,         /* Parent class */
                          get_string2,         /* Name of function */
                                               /* (no arguments) */
        );
    }
};

class NonCopyable {
public:
    NonCopyable(int a, int b) : value{new int(a * b)} { print_created(this, a, b); }
    NonCopyable(NonCopyable &&o) noexcept : value{std::move(o.value)} { print_move_created(this); }
    NonCopyable(const NonCopyable &) = delete;
    NonCopyable() = delete;
    void operator=(const NonCopyable &) = delete;
    void operator=(NonCopyable &&) = delete;
    std::string get_value() const {
        if (value) {
            return std::to_string(*value);
        }
        return "(null)";
    }
    ~NonCopyable() { print_destroyed(this); }

private:
    std::unique_ptr<int> value;
};

// This is like the above, but is both copy and movable.  In effect this means it should get moved
// when it is not referenced elsewhere, but copied if it is still referenced.
class Movable {
public:
    Movable(int a, int b) : value{a + b} { print_created(this, a, b); }
    Movable(const Movable &m) : value{m.value} { print_copy_created(this); }
    Movable(Movable &&m) noexcept : value{m.value} { print_move_created(this); }
    std::string get_value() const { return std::to_string(value); }
    ~Movable() { print_destroyed(this); }

private:
    int value;
};

class NCVirt {
public:
    virtual ~NCVirt() = default;
    NCVirt() = default;
    NCVirt(const NCVirt &) = delete;
    virtual NonCopyable get_noncopyable(int a, int b) { return NonCopyable(a, b); }
    virtual Movable get_movable(int a, int b) = 0;

    std::string print_nc(int a, int b) { return get_noncopyable(a, b).get_value(); }
    std::string print_movable(int a, int b) { return get_movable(a, b).get_value(); }
};
class NCVirtTrampoline : public NCVirt {
#if !defined(__INTEL_COMPILER) && !defined(__CUDACC__) && !defined(__PGIC__)
    NonCopyable get_noncopyable(int a, int b) override {
        PYBIND11_OVERRIDE(NonCopyable, NCVirt, get_noncopyable, a, b);
    }
#endif
    Movable get_movable(int a, int b) override {
        PYBIND11_OVERRIDE_PURE(Movable, NCVirt, get_movable, a, b);
    }
};

struct Base {
    virtual std::string dispatch() const = 0;
    virtual ~Base() = default;
    Base() = default;
    Base(const Base &) = delete;
};

struct DispatchIssue : Base {
    std::string dispatch() const override {
        PYBIND11_OVERRIDE_PURE(std::string, Base, dispatch, /* no arguments */);
    }
};

// An abstract adder class that uses visitor pattern to add two data
// objects and send the result to the visitor functor
struct AdderBase {
    struct Data {};
    using DataVisitor = std::function<void(const Data &)>;

    virtual void
    operator()(const Data &first, const Data &second, const DataVisitor &visitor) const = 0;
    virtual ~AdderBase() = default;
    AdderBase() = default;
    AdderBase(const AdderBase &) = delete;
};

struct Adder : AdderBase {
    void
    operator()(const Data &first, const Data &second, const DataVisitor &visitor) const override {
        PYBIND11_OVERRIDE_PURE_NAME(
            void, AdderBase, "__call__", operator(), first, second, visitor);
    }
};

static void test_gil() {
    {
        py::gil_scoped_acquire lock;
        py::print("1st lock acquired");
    }

    {
        py::gil_scoped_acquire lock;
        py::print("2nd lock acquired");
    }
}

static void test_gil_from_thread() {
    py::gil_scoped_release release;

    std::thread t(test_gil);
    t.join();
}

class test_override_cache_helper {

public:
    virtual int func() { return 0; }

    test_override_cache_helper() = default;
    virtual ~test_override_cache_helper() = default;
    // Non-copyable
    test_override_cache_helper &operator=(test_override_cache_helper const &Right) = delete;
    test_override_cache_helper(test_override_cache_helper const &Copy) = delete;
};

class test_override_cache_helper_trampoline : public test_override_cache_helper {
    int func() override { PYBIND11_OVERRIDE(int, test_override_cache_helper, func); }
};

inline int test_override_cache(std::shared_ptr<test_override_cache_helper> const &instance) {
    return instance->func();
}

// Forward declaration (so that we can put the main tests here; the inherited virtual approaches
// are rather long).
void initialize_inherited_virtuals(py::module_ &m);

TEST_SUBMODULE(virtual_functions, m) {
    // test_override
    py::class_<ExampleVirt, PyExampleVirt>(m, "ExampleVirt")
        .def(py::init<int>())
        /* Reference original class in function definitions */
        .def("run", &ExampleVirt::run)
        .def("run_bool", &ExampleVirt::run_bool)
        .def("pure_virtual", &ExampleVirt::pure_virtual);

    py::class_<NonCopyable>(m, "NonCopyable").def(py::init<int, int>());

    py::class_<Movable>(m, "Movable").def(py::init<int, int>());

    // test_move_support
#if !defined(__INTEL_COMPILER) && !defined(__CUDACC__) && !defined(__PGIC__)
    py::class_<NCVirt, NCVirtTrampoline>(m, "NCVirt")
        .def(py::init<>())
        .def("get_noncopyable", &NCVirt::get_noncopyable)
        .def("get_movable", &NCVirt::get_movable)
        .def("print_nc", &NCVirt::print_nc)
        .def("print_movable", &NCVirt::print_movable);
#endif

    m.def("runExampleVirt", [](ExampleVirt *ex, int value) { return ex->run(value); });
    m.def("runExampleVirtBool", [](ExampleVirt *ex) { return ex->run_bool(); });
    m.def("runExampleVirtVirtual", [](ExampleVirt *ex) { ex->pure_virtual(); });

    m.def("cstats_debug", &ConstructorStats::get<ExampleVirt>);
    initialize_inherited_virtuals(m);

    // test_alias_delay_initialization1
    // don't invoke Python dispatch classes by default when instantiating C++ classes
    // that were not extended on the Python side
    struct A {
        A() = default;
        A(const A &) = delete;
        virtual ~A() = default;
        virtual void f() { py::print("A.f()"); }
    };

    struct PyA : A {
        PyA() { py::print("PyA.PyA()"); }
        PyA(const PyA &) = delete;
        ~PyA() override { py::print("PyA.~PyA()"); }

        void f() override {
            py::print("PyA.f()");
            // This convolution just gives a `void`, but tests that PYBIND11_TYPE() works to
            // protect a type containing a ,
            PYBIND11_OVERRIDE(PYBIND11_TYPE(typename std::enable_if<true, void>::type), A, f);
        }
    };

    py::class_<A, PyA>(m, "A").def(py::init<>()).def("f", &A::f);

    m.def("call_f", [](A *a) { a->f(); });

    // test_alias_delay_initialization2
    // ... unless we explicitly request it, as in this example:
    struct A2 {
        A2() = default;
        A2(const A2 &) = delete;
        virtual ~A2() = default;
        virtual void f() { py::print("A2.f()"); }
    };

    struct PyA2 : A2 {
        PyA2() { py::print("PyA2.PyA2()"); }
        PyA2(const PyA2 &) = delete;
        ~PyA2() override { py::print("PyA2.~PyA2()"); }
        void f() override {
            py::print("PyA2.f()");
            PYBIND11_OVERRIDE(void, A2, f);
        }
    };

    py::class_<A2, PyA2>(m, "A2")
        .def(py::init_alias<>())
        .def(py::init([](int) { return new PyA2(); }))
        .def("f", &A2::f);

    m.def("call_f", [](A2 *a2) { a2->f(); });

    // test_dispatch_issue
    // #159: virtual function dispatch has problems with similar-named functions
    py::class_<Base, DispatchIssue>(m, "DispatchIssue")
        .def(py::init<>())
        .def("dispatch", &Base::dispatch);

    m.def("dispatch_issue_go", [](const Base *b) { return b->dispatch(); });

    // test_recursive_dispatch_issue
    // #3357: Recursive dispatch fails to find python function override
    pybind11::class_<AdderBase, Adder>(m, "Adder")
        .def(pybind11::init<>())
        .def("__call__", &AdderBase::operator());

    pybind11::class_<AdderBase::Data>(m, "Data").def(pybind11::init<>());

    m.def("add2",
          [](const AdderBase::Data &first,
             const AdderBase::Data &second,
             const AdderBase &adder,
             const AdderBase::DataVisitor &visitor) { adder(first, second, visitor); });

    m.def("add3",
          [](const AdderBase::Data &first,
             const AdderBase::Data &second,
             const AdderBase::Data &third,
             const AdderBase &adder,
             const AdderBase::DataVisitor &visitor) {
              adder(first, second, [&](const AdderBase::Data &first_plus_second) {
                  // NOLINTNEXTLINE(readability-suspicious-call-argument)
                  adder(first_plus_second, third, visitor);
              });
          });

    // test_override_ref
    // #392/397: overriding reference-returning functions
    class OverrideTest {
    public:
        struct A {
            std::string value = "hi";
        };
        std::string v;
        A a;
        explicit OverrideTest(const std::string &v) : v{v} {}
        OverrideTest() = default;
        OverrideTest(const OverrideTest &) = delete;
        virtual std::string str_value() { return v; }
        virtual std::string &str_ref() { return v; }
        virtual A A_value() { return a; }
        virtual A &A_ref() { return a; }
        virtual ~OverrideTest() = default;
    };

    class PyOverrideTest : public OverrideTest {
    public:
        using OverrideTest::OverrideTest;
        std::string str_value() override {
            PYBIND11_OVERRIDE(std::string, OverrideTest, str_value);
        }
        // Not allowed (enabling the below should hit a static_assert failure): we can't get a
        // reference to a python numeric value, since we only copy values in the numeric type
        // caster:
#ifdef PYBIND11_NEVER_DEFINED_EVER
        std::string &str_ref() override {
            PYBIND11_OVERRIDE(std::string &, OverrideTest, str_ref);
        }
#endif
        // But we can work around it like this:
    private:
        std::string _tmp;
        std::string str_ref_helper() { PYBIND11_OVERRIDE(std::string, OverrideTest, str_ref); }

    public:
        std::string &str_ref() override { return _tmp = str_ref_helper(); }

        A A_value() override { PYBIND11_OVERRIDE(A, OverrideTest, A_value); }
        A &A_ref() override { PYBIND11_OVERRIDE(A &, OverrideTest, A_ref); }
    };

    py::class_<OverrideTest::A>(m, "OverrideTest_A")
        .def_readwrite("value", &OverrideTest::A::value);
    py::class_<OverrideTest, PyOverrideTest>(m, "OverrideTest")
        .def(py::init<const std::string &>())
        .def("str_value", &OverrideTest::str_value)
#ifdef PYBIND11_NEVER_DEFINED_EVER
        .def("str_ref", &OverrideTest::str_ref)
#endif
        .def("A_value", &OverrideTest::A_value)
        .def("A_ref", &OverrideTest::A_ref);

    py::class_<test_override_cache_helper,
               test_override_cache_helper_trampoline,
               std::shared_ptr<test_override_cache_helper>>(m, "test_override_cache_helper")
        .def(py::init_alias<>())
        .def("func", &test_override_cache_helper::func);

    m.def("test_override_cache", test_override_cache);
}

// Inheriting virtual methods.  We do two versions here: the repeat-everything version and the
// templated trampoline versions mentioned in docs/advanced.rst.
//
// These base classes are exactly the same, but we technically need distinct
// classes for this example code because we need to be able to bind them
// properly (pybind11, sensibly, doesn't allow us to bind the same C++ class to
// multiple python classes).
class A_Repeat {
#define A_METHODS                                                                                 \
public:                                                                                           \
    virtual int unlucky_number() = 0;                                                             \
    virtual std::string say_something(unsigned times) {                                           \
        std::string s = "";                                                                       \
        for (unsigned i = 0; i < times; ++i)                                                      \
            s += "hi";                                                                            \
        return s;                                                                                 \
    }                                                                                             \
    std::string say_everything() {                                                                \
        return say_something(1) + " " + std::to_string(unlucky_number());                         \
    }
    A_METHODS
    A_Repeat() = default;
    A_Repeat(const A_Repeat &) = delete;
    virtual ~A_Repeat() = default;
};
class B_Repeat : public A_Repeat {
#define B_METHODS                                                                                 \
public:                                                                                           \
    int unlucky_number() override { return 13; }                                                  \
    std::string say_something(unsigned times) override {                                          \
        return "B says hi " + std::to_string(times) + " times";                                   \
    }                                                                                             \
    virtual double lucky_number() { return 7.0; }
    B_METHODS
};
class C_Repeat : public B_Repeat {
#define C_METHODS                                                                                 \
public:                                                                                           \
    int unlucky_number() override { return 4444; }                                                \
    double lucky_number() override { return 888; }
    C_METHODS
};
class D_Repeat : public C_Repeat {
#define D_METHODS // Nothing overridden.
    D_METHODS
};

// Base classes for templated inheritance trampolines.  Identical to the repeat-everything version:
class A_Tpl {
    A_METHODS;
    A_Tpl() = default;
    A_Tpl(const A_Tpl &) = delete;
    virtual ~A_Tpl() = default;
};
class B_Tpl : public A_Tpl {
    B_METHODS
};
class C_Tpl : public B_Tpl {
    C_METHODS
};
class D_Tpl : public C_Tpl {
    D_METHODS
};

// Inheritance approach 1: each trampoline gets every virtual method (11 in total)
class PyA_Repeat : public A_Repeat {
public:
    using A_Repeat::A_Repeat;
    int unlucky_number() override { PYBIND11_OVERRIDE_PURE(int, A_Repeat, unlucky_number, ); }
    std::string say_something(unsigned times) override {
        PYBIND11_OVERRIDE(std::string, A_Repeat, say_something, times);
    }
};
class PyB_Repeat : public B_Repeat {
public:
    using B_Repeat::B_Repeat;
    int unlucky_number() override { PYBIND11_OVERRIDE(int, B_Repeat, unlucky_number, ); }
    std::string say_something(unsigned times) override {
        PYBIND11_OVERRIDE(std::string, B_Repeat, say_something, times);
    }
    double lucky_number() override { PYBIND11_OVERRIDE(double, B_Repeat, lucky_number, ); }
};
class PyC_Repeat : public C_Repeat {
public:
    using C_Repeat::C_Repeat;
    int unlucky_number() override { PYBIND11_OVERRIDE(int, C_Repeat, unlucky_number, ); }
    std::string say_something(unsigned times) override {
        PYBIND11_OVERRIDE(std::string, C_Repeat, say_something, times);
    }
    double lucky_number() override { PYBIND11_OVERRIDE(double, C_Repeat, lucky_number, ); }
};
class PyD_Repeat : public D_Repeat {
public:
    using D_Repeat::D_Repeat;
    int unlucky_number() override { PYBIND11_OVERRIDE(int, D_Repeat, unlucky_number, ); }
    std::string say_something(unsigned times) override {
        PYBIND11_OVERRIDE(std::string, D_Repeat, say_something, times);
    }
    double lucky_number() override { PYBIND11_OVERRIDE(double, D_Repeat, lucky_number, ); }
};

// Inheritance approach 2: templated trampoline classes.
//
// Advantages:
// - we have only 2 (template) class and 4 method declarations (one per virtual method, plus one
//   for any override of a pure virtual method), versus 4 classes and 6 methods (MI) or 4 classes
//   and 11 methods (repeat).
// - Compared to MI, we also don't have to change the non-trampoline inheritance to virtual, and
//   can properly inherit constructors.
//
// Disadvantage:
// - the compiler must still generate and compile 14 different methods (more, even, than the 11
//   required for the repeat approach) instead of the 6 required for MI.  (If there was no pure
//   method (or no pure method override), the number would drop down to the same 11 as the repeat
//   approach).
template <class Base = A_Tpl>
class PyA_Tpl : public Base {
public:
    using Base::Base; // Inherit constructors
    int unlucky_number() override { PYBIND11_OVERRIDE_PURE(int, Base, unlucky_number, ); }
    std::string say_something(unsigned times) override {
        PYBIND11_OVERRIDE(std::string, Base, say_something, times);
    }
};
template <class Base = B_Tpl>
class PyB_Tpl : public PyA_Tpl<Base> {
public:
    using PyA_Tpl<Base>::PyA_Tpl; // Inherit constructors (via PyA_Tpl's inherited constructors)
    // NOLINTNEXTLINE(bugprone-parent-virtual-call)
    int unlucky_number() override { PYBIND11_OVERRIDE(int, Base, unlucky_number, ); }
    double lucky_number() override { PYBIND11_OVERRIDE(double, Base, lucky_number, ); }
};
// Since C_Tpl and D_Tpl don't declare any new virtual methods, we don't actually need these
// (we can use PyB_Tpl<C_Tpl> and PyB_Tpl<D_Tpl> for the trampoline classes instead):
/*
template <class Base = C_Tpl> class PyC_Tpl : public PyB_Tpl<Base> {
public:
    using PyB_Tpl<Base>::PyB_Tpl;
};
template <class Base = D_Tpl> class PyD_Tpl : public PyC_Tpl<Base> {
public:
    using PyC_Tpl<Base>::PyC_Tpl;
};
*/

void initialize_inherited_virtuals(py::module_ &m) {
    // test_inherited_virtuals

    // Method 1: repeat
    py::class_<A_Repeat, PyA_Repeat>(m, "A_Repeat")
        .def(py::init<>())
        .def("unlucky_number", &A_Repeat::unlucky_number)
        .def("say_something", &A_Repeat::say_something)
        .def("say_everything", &A_Repeat::say_everything);
    py::class_<B_Repeat, A_Repeat, PyB_Repeat>(m, "B_Repeat")
        .def(py::init<>())
        .def("lucky_number", &B_Repeat::lucky_number);
    py::class_<C_Repeat, B_Repeat, PyC_Repeat>(m, "C_Repeat").def(py::init<>());
    py::class_<D_Repeat, C_Repeat, PyD_Repeat>(m, "D_Repeat").def(py::init<>());

    // test_
    // Method 2: Templated trampolines
    py::class_<A_Tpl, PyA_Tpl<>>(m, "A_Tpl")
        .def(py::init<>())
        .def("unlucky_number", &A_Tpl::unlucky_number)
        .def("say_something", &A_Tpl::say_something)
        .def("say_everything", &A_Tpl::say_everything);
    py::class_<B_Tpl, A_Tpl, PyB_Tpl<>>(m, "B_Tpl")
        .def(py::init<>())
        .def("lucky_number", &B_Tpl::lucky_number);
    py::class_<C_Tpl, B_Tpl, PyB_Tpl<C_Tpl>>(m, "C_Tpl").def(py::init<>());
    py::class_<D_Tpl, C_Tpl, PyB_Tpl<D_Tpl>>(m, "D_Tpl").def(py::init<>());

    // Fix issue #1454 (crash when acquiring/releasing GIL on another thread in Python 2.7)
    m.def("test_gil", &test_gil);
    m.def("test_gil_from_thread", &test_gil_from_thread);
};
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