The following program makes Python 3.4.3 crash with a segmentation fault:
```
#!/usr/bin/env python3
import operator
N = 500000
l = [0]
for i in range(N):
l = map(operator.add, l, [1])
print(list(l))
```
I suppose the problem is that there are too many nested lazy calls to map, which cause a segfault when evaluated. I've played with N and surprisingly, the threshold to cause the crash varied slightly (between 130900 and 131000 on my machine).
I know that a list-comprehension, which is evaluated straight away, would be much more idiomatic for repeated element-wise addition (or numpy arrays for that matter, if available). I'm **not advocating this piece of code**, just wondering whether there couldn't be a more informative way to make Python bail out instead of the segfault? (In my real application, it took me a while to figure where the problem was without a stack trace.)
Process 51270 launched: './python' (x86_64)
Process 51270 stopped
* thread #1: tid = 0x5c8677, 0x00000001000c1af8 python`_PyObject_Alloc(use_calloc=0, ctx=<unavailable>, nelem=<unavailable>, elsize=<unavailable>) + 24 at obmalloc.c:1170, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=2, address=0x7fff5ebffff8)
frame #0: 0x00000001000c1af8 python`_PyObject_Alloc(use_calloc=0, ctx=<unavailable>, nelem=<unavailable>, elsize=<unavailable>) + 24 at obmalloc.c:1170
1167
1168 static void *
1169 _PyObject_Alloc(int use_calloc, void *ctx, size_t nelem, size_t elsize)
-> 1170 {
1171 size_t nbytes;
1172 block *bp;
1173 poolp pool;
(lldb) bt
* thread #1: tid = 0x5c8677, 0x00000001000c1af8 python`_PyObject_Alloc(use_calloc=0, ctx=<unavailable>, nelem=<unavailable>, elsize=<unavailable>) + 24 at obmalloc.c:1170, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=2, address=0x7fff5ebffff8)
* frame #0: 0x00000001000c1af8 python`_PyObject_Alloc(use_calloc=0, ctx=<unavailable>, nelem=<unavailable>, elsize=<unavailable>) + 24 at obmalloc.c:1170
frame #1: 0x00000001000c0ec8 python`_PyObject_Malloc(ctx=0x0000000000000000, nbytes=112) + 40 at obmalloc.c:1386
frame #2: 0x00000001000c03e9 python`_PyMem_DebugAlloc(use_calloc=0, ctx=0x0000000100390898, nbytes=80) + 153 at obmalloc.c:1838
frame #3: 0x00000001000be981 python`_PyMem_DebugMalloc(ctx=0x0000000100390898, nbytes=80) + 33 at obmalloc.c:1861
frame #4: 0x00000001000bf3c1 python`PyObject_Malloc(size=80) + 65 at obmalloc.c:386
frame #5: 0x000000010028c87e python`_PyObject_GC_Alloc(use_calloc=0, basicsize=56) + 110 at gcmodule.c:1696
frame #6: 0x000000010028c809 python`_PyObject_GC_Malloc(basicsize=56) + 25 at gcmodule.c:1718
frame #7: 0x000000010028ca6d python`_PyObject_GC_NewVar(tp=0x0000000100393990, nitems=2) + 109 at gcmodule.c:1747
frame #8: 0x00000001000d6c82 python`PyTuple_New(size=2) + 338 at tupleobject.c:104
frame #9: 0x00000001001d7e26 python`map_next(lz=0x000000010cebbae8) + 38 at bltinmodule.c:1162
frame #10: 0x000000010001072c python`PyIter_Next(iter=0x000000010cebbae8) + 44 at abstract.c:2760
frame #11: 0x00000001001d7e71 python`map_next(lz=0x000000010cebbbb8) + 113 at bltinmodule.c:1167
frame #12: 0x000000010001072c python`PyIter_Next(iter=0x000000010cebbbb8) + 44 at abstract.c:2760
frame #13: 0x00000001001d7e71 python`map_next(lz=0x000000010cebbc88) + 113 at bltinmodule.c:1167
frame #14: 0x000000010001072c python`PyIter_Next(iter=0x000000010cebbc88) + 44 at abstract.c:2760
frame #15: 0x00000001001d7e71 python`map_next(lz=0x000000010cebbd58) + 113 at bltinmodule.c:1167
frame #16: 0x000000010001072c python`PyIter_Next(iter=0x000000010cebbd58) + 44 at abstract.c:2760
frame #17: 0x00000001001d7e71 python`map_next(lz=0x000000010cebbe28) + 113 at bltinmodule.c:1167
frame #18: 0x000000010001072c python`PyIter_Next(iter=0x000000010cebbe28) + 44 at abstract.c:2760
frame #19: 0x00000001001d7e71 python`map_next(lz=0x000000010cebbef8) + 113 at bltinmodule.c:1167
frame #20: 0x000000010001072c python`PyIter_Next(iter=0x000000010cebbef8) + 44 at abstract.c:2760
frame #21: 0x00000001001d7e71 python`map_next(lz=0x000000010cebd058) + 113 at bltinmodule.c:1167
frame #22: 0x000000010001072c python`PyIter_Next(iter=0x000000010cebd058) + 44 at abstract.c:2760
frame #23: 0x00000001001d7e71 python`map_next(lz=0x000000010cebd128) + 113 at bltinmodule.c:1167
frame #24: 0x000000010001072c python`PyIter_Next(iter=0x000000010cebd128) + 44 at abstract.c:2760
[...]