Our package build process currently has a significant flaw: we first run `setup.py`, recording all compilation commands, then we rewrite these compilation commands to invoke `emcc` and replay them, and then we pray that the cross compiled executables ended up in the right place to go into the wheel. This is not a good strategy because the build script is allowed to implement arbitrary logic, and if it moves, renames, etc any of the output files then we lose track of them. This has repeatedly caused difficulty for us.

However, we also make no particularly significant use of the two pass approach. We can just do the simpler thing: capture the compiler commands as they occur, modify them as needed, and then run the fixed command.

I also added a patch to fix the numpy feature detection for wasm so that we don't have to include `_npyconfig.h` and `config.h`, numpy can generate them in the way it would for a native build. I opened a numpy PR that would fix the detection for us upstream:
https://github.com/numpy/numpy/pull/21154

This clears the way for us to switch to using pypa/build (as @henryiii has suggested) by removing our dependence on specific setuptools behavior.

This is on top of #2238.
No replay. Our package build process currently has a significant flaw: we first run `setup.py`, recording all compilation commands, then we rewrite these compilation commands to invoke `emcc` and replay them, and then we pray that the cross compiled executables ended up in the right place to go into the wheel. This is not a good strategy because the build script is allowed to implement arbitrary logic, and if it moves, renames, etc any of the output files then we lose track of them. This has repeatedly caused difficulty for us.

However, we also make no particularly significant use of the two pass approach. We can just do the simpler thing: capture the compiler commands as they occur, modify them as needed, and then run the fixed command.

I also added a patch to fix the numpy feature detection for wasm so that we don't have to include `_npyconfig.h` and `config.h`, numpy can generate them in the way it would for a native build. I opened a numpy PR that would fix the detection for us upstream:
https://github.com/numpy/numpy/pull/21154

This clears the way for us to switch to using pypa/build (as @henryiii has suggested) by removing our dependence on specific setuptools behavior.

This is on top of #2238.
from dataclasses import dataclass

import pytest

from pyodide_build.pywasmcross import replay_command  # noqa: E402
from pyodide_build.pywasmcross import replay_f2c  # noqa: E402
from pyodide_build.pywasmcross import environment_substitute_args


@dataclass
class BuildArgs:
    """An object to hold build arguments"""

    cflags: str = ""
    cxxflags: str = ""
    ldflags: str = ""
    replace_libs: str = ""
    host_install_dir: str = ""
    target_install_dir: str = ""


def _args_wrapper(func):
    """Convert function to take as input / return a string instead of a
    list of arguments

    Also sets dryrun=True
    """

    def _inner(line, *pargs):
        args = line.split()
        res = func(args, *pargs, dryrun=True)
        if hasattr(res, "__len__"):
            return " ".join(res)
        else:
            return res

    return _inner


replay_command_wrap = _args_wrapper(replay_command)
f2c_wrap = _args_wrapper(replay_f2c)


def test_handle_command():
    args = BuildArgs()
    assert replay_command_wrap("gcc -print-multiarch", args) is None
    assert replay_command_wrap("gcc test.c", args) == "emcc test.c"
    assert (
        replay_command_wrap("gcc -shared -c test.o -o test.so", args)
        == "emcc -c test.o -o test.so"
    )

    # check cxxflags injection and cpp detection
    args = BuildArgs(
        cflags="-I./lib2",
        cxxflags="-std=c++11",
        ldflags="-lm",
    )
    assert (
        replay_command_wrap("gcc -I./lib1 test.cpp -o test.o", args)
        == "em++ -I./lib2 -std=c++11 -I./lib1 test.cpp -o test.o"
    )

    # check ldflags injection
    args = BuildArgs(
        cflags="",
        cxxflags="",
        ldflags="-lm",
        host_install_dir="",
        replace_libs="",
        target_install_dir="",
    )
    assert (
        replay_command_wrap("gcc -shared -c test.o -o test.so", args)
        == "emcc -lm -c test.o -o test.so"
    )

    # check library replacement and removal of double libraries
    args = BuildArgs(
        replace_libs="bob=fred",
    )
    assert (
        replay_command_wrap("gcc -shared test.o -lbob -ljim -ljim -o test.so", args)
        == "emcc test.o -lfred -ljim -o test.so"
    )

    # compilation checks in numpy
    assert replay_command_wrap("gcc /usr/file.c", args) is None


def test_handle_command_ldflags():
    # Make sure to remove unsupported link flags for wasm-ld

    args = BuildArgs()
    assert (
        replay_command_wrap(
            "gcc -Wl,--strip-all,--as-needed -Wl,--sort-common,-z,now,-Bsymbolic-functions -shared -c test.o -o test.so",
            args,
        )
        == "emcc -Wl,-z,now -c test.o -o test.so"
    )


@pytest.mark.parametrize(
    "in_ext, out_ext, executable, flag_name",
    [
        (".c", ".o", "emcc", "cflags"),
        (".cpp", ".o", "em++", "cxxflags"),
        (".c", ".so", "emcc", "ldflags"),
    ],
)
def test_handle_command_optflags(in_ext, out_ext, executable, flag_name):
    # Make sure that when multiple optflags are present those in cflags,
    # cxxflags, or ldflags has priority

    args = BuildArgs(**{flag_name: "-Oz"})
    assert (
        replay_command_wrap(f"gcc -O3 test.{in_ext} -o test.{out_ext}", args)
        == f"{executable} -Oz test.{in_ext} -o test.{out_ext}"
    )


def test_f2c():
    assert f2c_wrap("gfortran test.f") == "gcc test.c"
    assert f2c_wrap("gcc test.c") is None
    assert f2c_wrap("gfortran --version") is None
    assert (
        f2c_wrap("gfortran --shared -c test.o -o test.so")
        == "gcc --shared -c test.o -o test.so"
    )


def test_conda_unsupported_args():
    # Check that compile arguments that are not supported by emcc and are sometimes
    # used in conda are removed.
    args = BuildArgs()
    assert replay_command_wrap(
        "gcc -shared -c test.o -B /compiler_compat -o test.so", args
    ) == ("emcc -c test.o -o test.so")

    assert replay_command_wrap(
        "gcc -shared -c test.o -Wl,--sysroot=/ -o test.so", args
    ) == ("emcc -c test.o -o test.so")


def test_environment_var_substitution(monkeypatch):
    monkeypatch.setenv("PYODIDE_BASE", "pyodide_build_dir")
    monkeypatch.setenv("BOB", "Robert Mc Roberts")
    monkeypatch.setenv("FRED", "Frederick F. Freddertson Esq.")
    monkeypatch.setenv("JIM", "James Ignatius Morrison:Jimmy")
    args = environment_substitute_args(
        {
            "ldflags": '"-l$(PYODIDE_BASE)"',
            "cxxflags": "$(BOB)",
            "cflags": "$(FRED)",
            "replace_libs": "$(JIM)",
        }
    )
    assert (
        args["cflags"] == "Frederick F. Freddertson Esq."
        and args["cxxflags"] == "Robert Mc Roberts"
        and args["ldflags"] == '"-lpyodide_build_dir"'
        and args["replace_libs"] == "James Ignatius Morrison:Jimmy"
    )

from dataclasses import dataclass

import pytest

from pyodide_build.pywasmcross import handle_command_generate_args  # noqa: E402
from pyodide_build.pywasmcross import replay_f2c  # noqa: E402
from pyodide_build.pywasmcross import environment_substitute_args


@dataclass
class BuildArgs:
    """An object to hold build arguments"""

    cflags: str = ""
    cxxflags: str = ""
    ldflags: str = ""
    replace_libs: str = ""
    host_install_dir: str = ""
    target_install_dir: str = ""


def _args_wrapper(func):
    """Convert function to take as input / return a string instead of a
    list of arguments

    Also sets dryrun=True
    """

    def _inner(line, *pargs):
        args = line.split()
        res = func(args, *pargs, dryrun=True)
        if hasattr(res, "__len__"):
            return " ".join(res)
        else:
            return res

    return _inner


f2c_wrap = _args_wrapper(replay_f2c)


def generate_args(line: str, args, is_link_cmd=False) -> str:
    splitline = line.split()
    res = handle_command_generate_args(splitline, args, is_link_cmd)
    for arg in [
        "-Werror=implicit-function-declaration",
        "-Werror=mismatched-parameter-types",
        "-Werror=return-type",
    ]:
        assert arg in res
        res.remove(arg)
    if is_link_cmd:
        arg = "-Wl,--fatal-warnings"
        assert arg in res
        res.remove(arg)
    return " ".join(res)


def test_handle_command():
    args = BuildArgs()
    assert handle_command_generate_args(["gcc", "-print-multiarch"], args, True) == [  # type: ignore[arg-type]
        "echo",
        "wasm32-emscripten",
    ]
    assert generate_args("gcc test.c", args) == "emcc test.c"
    assert (
        generate_args("gcc -shared -c test.o -o test.so", args, True)
        == "emcc -c test.o -o test.so"
    )

    # check cxxflags injection and cpp detection
    args = BuildArgs(
        cflags="-I./lib2",
        cxxflags="-std=c++11",
        ldflags="-lm",
    )
    assert (
        generate_args("gcc -I./lib1 -c test.cpp -o test.o", args)
        == "em++ -I./lib2 -std=c++11 -I./lib1 -c test.cpp -o test.o"
    )

    # check ldflags injection
    args = BuildArgs(
        cflags="",
        cxxflags="",
        ldflags="-lm",
        host_install_dir="",
        replace_libs="",
        target_install_dir="",
    )
    assert (
        generate_args("gcc -shared -c test.o -o test.so", args, True)
        == "emcc -lm -c test.o -o test.so"
    )

    # check library replacement and removal of double libraries
    args = BuildArgs(
        replace_libs="bob=fred",
    )
    assert (
        generate_args("gcc -shared test.o -lbob -ljim -ljim -o test.so", args)
        == "emcc test.o -lfred -ljim -o test.so"
    )


def test_handle_command_ldflags():
    # Make sure to remove unsupported link flags for wasm-ld

    args = BuildArgs()
    assert (
        generate_args(
            "gcc -Wl,--strip-all,--as-needed -Wl,--sort-common,-z,now,-Bsymbolic-functions -shared -c test.o -o test.so",
            args,
            True,
        )
        == "emcc -Wl,-z,now -c test.o -o test.so"
    )


@pytest.mark.parametrize(
    "in_ext, out_ext, executable, flag_name",
    [
        (".c", ".o", "emcc", "cflags"),
        (".cpp", ".o", "em++", "cxxflags"),
        (".c", ".so", "emcc", "ldflags"),
    ],
)
def test_handle_command_optflags(in_ext, out_ext, executable, flag_name):
    # Make sure that when multiple optflags are present those in cflags,
    # cxxflags, or ldflags has priority

    args = BuildArgs(**{flag_name: "-Oz"})
    assert (
        generate_args(f"gcc -O3 -c test.{in_ext} -o test.{out_ext}", args, True)
        == f"{executable} -Oz -c test.{in_ext} -o test.{out_ext}"
    )


def test_f2c():
    assert f2c_wrap("gfortran test.f") == "gcc test.c"
    assert f2c_wrap("gcc test.c") is None
    assert f2c_wrap("gfortran --version") is None
    assert (
        f2c_wrap("gfortran --shared -c test.o -o test.so")
        == "gcc --shared -c test.o -o test.so"
    )


def test_conda_unsupported_args():
    # Check that compile arguments that are not supported by emcc and are sometimes
    # used in conda are removed.
    args = BuildArgs()
    assert generate_args(
        "gcc -shared -c test.o -B /compiler_compat -o test.so", args
    ) == ("emcc -c test.o -o test.so")

    assert generate_args("gcc -shared -c test.o -Wl,--sysroot=/ -o test.so", args) == (
        "emcc -c test.o -o test.so"
    )


def test_environment_var_substitution(monkeypatch):
    monkeypatch.setenv("PYODIDE_BASE", "pyodide_build_dir")
    monkeypatch.setenv("BOB", "Robert Mc Roberts")
    monkeypatch.setenv("FRED", "Frederick F. Freddertson Esq.")
    monkeypatch.setenv("JIM", "James Ignatius Morrison:Jimmy")
    args = environment_substitute_args(
        {
            "ldflags": '"-l$(PYODIDE_BASE)"',
            "cxxflags": "$(BOB)",
            "cflags": "$(FRED)",
            "replace_libs": "$(JIM)",
        }
    )
    assert (
        args["cflags"] == "Frederick F. Freddertson Esq."
        and args["cxxflags"] == "Robert Mc Roberts"
        and args["ldflags"] == '"-lpyodide_build_dir"'
        and args["replace_libs"] == "James Ignatius Morrison:Jimmy"
    )
