view mercurial/cffi/mpatchbuild.py @ 51730:63ede7a43a37 stable

demandimport: don't delay threading import

A recent cpython change breaks demandimport by importing threading
locally in importlib.util.LazyLoader.exec_module; add it (plus warnings
and _weakrefset, which are imported by threading) to demandimport's
ignore list.

```
Traceback (most recent call last):
  File "/usr/bin/hg", line 57, in <module>
    from mercurial import dispatch
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "/usr/lib/python3/dist-packages/hgdemandimport/demandimportpy3.py", line 52, in exec_module
    super().exec_module(module)
  File "<frozen importlib.util>", line 257, in exec_module
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "/usr/lib/python3/dist-packages/hgdemandimport/demandimportpy3.py", line 52, in exec_module
    super().exec_module(module)
  File "<frozen importlib.util>", line 267, in exec_module
AttributeError: partially initialized module 'threading' has no attribute 'RLock' (most likely due to a circular import)
```

Ref: https://github.com/python/cpython/issues/117983
     https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1076449
     https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1076747

import cffi
import os

ffi = cffi.FFI()
mpatch_c = os.path.join(
    os.path.join(os.path.dirname(__file__), '..', 'mpatch.c')
)
with open(mpatch_c) as f:
    ffi.set_source(
        "mercurial.cffi._mpatch", f.read(), include_dirs=["mercurial"]
    )
ffi.cdef(
    """

struct mpatch_frag {
       int start, end, len;
       const char *data;
};

struct mpatch_flist {
       struct mpatch_frag *base, *head, *tail;
};

extern "Python" struct mpatch_flist* cffi_get_next_item(void*, ssize_t);

int mpatch_decode(const char *bin, ssize_t len, struct mpatch_flist** res);
ssize_t mpatch_calcsize(size_t len, struct mpatch_flist *l);
void mpatch_lfree(struct mpatch_flist *a);
static int mpatch_apply(char *buf, const char *orig, size_t len,
                        struct mpatch_flist *l);
struct mpatch_flist *mpatch_fold(void *bins,
                       struct mpatch_flist* (*get_next_item)(void*, ssize_t),
                       ssize_t start, ssize_t end);
"""
)

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