mergerfs/tests/TEST_posix_fsync_flush

#!/usr/bin/env python3

import os
import sys
import tempfile

from posix_parity import cleanup_dir
from posix_parity import compare_calls
from posix_parity import fail
from posix_parity import join
from posix_parity import mergerfs_mount
from posix_parity import temp_dir
from posix_parity import touch


def main():
    try:
        with mergerfs_mount() as (mount, _):
            with tempfile.TemporaryDirectory() as native:
                merge_base = temp_dir(mount)
                try:
                    native_base = join(native, os.path.basename(merge_base))
                    os.makedirs(native_base, exist_ok=True)

                    merge_file = join(merge_base, "file")
                    native_file = join(native_base, "file")
                    merge_dir = join(merge_base, "dir")
                    native_dir = join(native_base, "dir")

                    touch(merge_file, b"abc")
                    touch(native_file, b"abc")
                    os.makedirs(merge_dir, exist_ok=True)
                    os.makedirs(native_dir, exist_ok=True)

                    mfd = os.open(merge_file, os.O_RDWR)
                    nfd = os.open(native_file, os.O_RDWR)
                    try:
                        os.lseek(mfd, 0, os.SEEK_END)
                        os.lseek(nfd, 0, os.SEEK_END)
                        os.write(mfd, b"-appended")
                        os.write(nfd, b"-appended")

                        err = compare_calls("fsync file", lambda: os.fsync(mfd), lambda: os.fsync(nfd))
                        if err:
                            return fail(err)
                    finally:
                        os.close(mfd)
                        os.close(nfd)

                    mdirfd = os.open(merge_dir, os.O_RDONLY | os.O_DIRECTORY)
                    ndirfd = os.open(native_dir, os.O_RDONLY | os.O_DIRECTORY)
                    try:
                        err = compare_calls("fsync dir", lambda: os.fsync(mdirfd), lambda: os.fsync(ndirfd))
                        if err:
                            return fail(err)
                    finally:
                        os.close(mdirfd)
                        os.close(ndirfd)

                    bad_m = os.open(merge_file, os.O_RDONLY)
                    bad_n = os.open(native_file, os.O_RDONLY)
                    os.close(bad_m)
                    os.close(bad_n)
                    err = compare_calls("fsync EBADF", lambda: os.fsync(bad_m), lambda: os.fsync(bad_n))
                    if err:
                        return fail(err)

                    with open(merge_file, "rb") as mf, open(native_file, "rb") as nf:
                        mdata = mf.read()
                        ndata = nf.read()
                    if mdata != ndata:
                        return fail(f"flush content mismatch mergerfs={mdata!r} native={ndata!r}")

                    return 0
                finally:
                    cleanup_dir(merge_base)
    except RuntimeError as exc:
        print(str(exc), end="")
        return 77


if __name__ == "__main__":
    raise SystemExit(main())