[Numpy-discussion] Obscure code in concatenate code path?

Hi, While writing some tests for np.concatenate, I ran foul of this code: if (axis >= NPY_MAXDIMS) { ret = PyArray_ConcatenateFlattenedArrays(narrays, arrays, NPY_CORDER); } else { ret = PyArray_ConcatenateArrays(narrays, arrays, axis); } in multiarraymodule.c So, if the user passes an axis >= (by default) 32 the arrays to concatenate get flattened, and must all have the same number of elements (it turns out). This seems obscure. Obviously it is not likely that someone would pass in an axis no >= 32 by accident, but if they did, they would not get the result they expect. Is there some code-path that needs this? Is there another way of doing it? Best, Matthew