setup_bdiff_cffi.py

demandimport: do not raise ImportError for unknown item in fromlist

This is the behavior of the default __import__() function, which doesn't
validate the existence of the fromlist items. Later on, the missing attribute
is detected while processing the import statement.

https://hg.python.org/cpython/file/v2.7.13/Python/import.c#l2575

The comtypes library relies on this (maybe) undocumented behavior, and we
got a bug report to TortoiseHg, sigh.

https://bitbucket.org/tortoisehg/thg/issues/4647/

The test added at 26a4e46af2bc verifies the behavior of the import statement,
so this patch only adds the test of __import__() function and works around
CPython/PyPy difference.

from __future__ import absolute_import

import cffi
import os

ffi = cffi.FFI()
ffi.set_source("_bdiff_cffi",
    open(os.path.join(os.path.join(os.path.dirname(__file__), 'mercurial'),
        'bdiff.c')).read(), include_dirs=['mercurial'])
ffi.cdef("""
struct bdiff_line {
    int hash, n, e;
    ssize_t len;
    const char *l;
};

struct bdiff_hunk;
struct bdiff_hunk {
    int a1, a2, b1, b2;
    struct bdiff_hunk *next;
};

int bdiff_splitlines(const char *a, ssize_t len, struct bdiff_line **lr);
int bdiff_diff(struct bdiff_line *a, int an, struct bdiff_line *b, int bn,
    struct bdiff_hunk *base);
void bdiff_freehunks(struct bdiff_hunk *l);
void free(void*);
""")

if __name__ == '__main__':
    ffi.compile()